Tim Van Wassenhove

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Mon, 01 Jan 0001 00:00:00 +0000

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Configuring Scaleway SAML SSO with Authentik

Tue, 24 Feb 2026 00:00:00 +0000

Introduction

In previous posts, I covered setting up Authentik with Kubernetes and FluxCD, managing Authentik with Terraform, and integrating it with services like Grafana, MinIO, and AWS IAM Identity Center. Today, I’ll walk through how I configured SAML SSO for Scaleway using Authentik as the identity provider, all managed with Terraform.

Scaleway is a European cloud provider headquartered in Paris. As part of a broader move towards digital sovereignty and reducing dependency on US-based cloud providers, Scaleway offers an attractive alternative with data centers located exclusively in Europe. Integrating it with a self-hosted identity provider like Authentik fits well into this approach: keeping both infrastructure and identity management under European jurisdiction.

Keep Your Bose SoundTouch Speaker Alive After the Shutdown

Tue, 17 Feb 2026 00:00:00 +0000

Bose is shutting down the SoundTouch cloud servers on May 6, 2026. Once they do, your TuneIn presets stop working, the SoundTouch app loses most functionality, and you can no longer configure presets.

The good news: you can fix all of this. SoundCork is a self-hosted replacement for the Bose cloud servers. It runs on anything — a Raspberry Pi, a NAS, a Docker host, a Kubernetes cluster. Your speaker talks to your server instead of Bose, and everything keeps working.

Never Lose an AI Coding Session Again

Mon, 16 Feb 2026 00:00:00 +0000

We’re at an inflection point for software development. AI coding assistants – Claude Code, OpenCode, Codex CLI – have crossed the threshold from novelty to genuine productivity multiplier. Developers who lean into these tools are shipping products faster and at higher quality, not because the AI writes perfect code, but because it handles the grunt work while you focus on architecture, decisions, and review.

If you’re running these tools seriously, you’re probably running multiple of them in parallel: one per project, one per task. tmux is the natural home for this workflow – split panes, named sessions, scriptable, works over SSH. If you’re new to tmux, I wrote about training wheels to ease the learning curve, and wt makes managing parallel worktrees painless.

wt: A Better Way to Manage Git Worktrees

Fri, 13 Feb 2026 00:00:00 +0000

If you work on multiple branches simultaneously, you’ve probably discovered git worktrees. They let you check out multiple branches at the same time in separate directories, without the overhead of cloning the repository again. The problem is that the built-in commands are tedious to use in practice. I built wt to fix that.

The Problem with Vanilla Git Worktrees

Using git worktree directly means you have to:

Manually specify full paths every time you create a worktree
Remember where you put each worktree on disk
Manually cd into the new directory after creating one
Come up with your own naming and organizational conventions
Clean up stale worktrees by hand when branches get merged

It’s powerful, but the workflow friction adds up quickly. After a while I found myself avoiding worktrees altogether simply because the ceremony around them was too high.

Tmux Training Wheels: A Zellij-Inspired Shortcut Hints Bar

Thu, 12 Feb 2026 10:00:00 +0100

I’ve been using tmux since around 2010, after years of working with GNU Screen. Tmux itself has been around since 2007, and over the years its shortcuts have become second nature to me. But I’ve noticed that when colleagues see my terminal setup and want to try tmux themselves, the keyboard shortcuts are the first barrier. They end up with a cheat sheet pinned to their monitor or open in a browser tab, constantly context-switching away from the terminal.

FastMCP Distributed Tracing: Transport-Agnostic Context Propagation with _meta

Tue, 14 Oct 2025 10:00:00 +0100

In my previous post about distributed tracing with FastMCP, I demonstrated how to propagate OpenTelemetry context using HTTP headers. While this approach worked well for HTTP-based deployments, it had a significant limitation: it only worked with HTTP transports.

Today, I’m sharing an improved implementation that uses the MCP protocol’s _meta field convention, making trace context propagation truly transport-agnostic.

The Problem with HTTP Headers

The original HTTP-header-based approach had several limitations:

Transport-Specific: Only worked with HTTP/SSE transports, not with stdio
Not Standard: Required transport-specific implementations
Limited Portability: Didn’t follow MCP protocol conventions

For MCP servers that need to support multiple transports (stdio for local development, HTTP for remote deployments, SSE for streaming), this was a real constraint.

Distributed Tracing with FastMCP: Combining OpenTelemetry and Langfuse

Fri, 27 Jun 2025 10:00:00 +0100

Update (October 2025): This post describes the original HTTP-header-based approach to trace context propagation. For a transport-agnostic solution that works with stdio, HTTP, and SSE transports, see the updated implementation using the MCP _meta field convention in my follow-up post: FastMCP Distributed Tracing: Transport-Agnostic Context Propagation with _meta.

When building distributed AI applications with FastMCP, proper observability becomes crucial. In this post, I’ll show you how to combine OpenTelemetry context propagation with Langfuse to achieve seamless distributed tracing across your MCP client and server components.

Implementing Domain-Level Forward Authentication with Authentik

Sat, 22 Mar 2025 00:00:00 +0000

Introduction

In my previous posts on Authentik, I’ve covered setting up the platform, managing it with Terraform, and integrating it with services like Grafana, MinIO, and AWS IAM Identity Center.

Today, I’ll explain how I implemented domain-level forward authentication to protect multiple applications in my Kubernetes cluster using Authentik’s forward auth provider and NGINX ingress controller.

Understanding Forward Authentication

Forward authentication is a pattern where a proxy (like NGINX) delegates the authentication decision to an external service (in our case, Authentik). This approach allows you to protect multiple applications without modifying their code or configurations.

Configuring AWS Identity Center with Authentik SCIM Provisioning

Fri, 21 Mar 2025 00:00:00 +0000

Introduction

In previous posts, I’ve covered setting up Authentik with Kubernetes and FluxCD, managing Authentik with Terraform, and integrating it with various services like Grafana and MinIO. Today, I’ll explain how I configured AWS IAM Identity Center (formerly AWS SSO) with Authentik using SCIM provisioning.

AWS IAM Identity Center has become a critical component for managing access to AWS accounts and applications. By integrating it with Authentik using SCIM (System for Cross-domain Identity Management), we can automate user provisioning and deprovisioning, centralize identity management, and implement consistent access controls across our AWS environment.

Configuring MinIO OAuth with Authentik

Thu, 20 Mar 2025 00:00:00 +0000

Introduction

Following our previous posts about setting up Authentik with Kubernetes and FluxCD, managing Authentik with Terraform, and configuring Grafana OAuth integration, today I’ll share how I implemented OAuth authentication for MinIO using Authentik as the identity provider.

MinIO is a high-performance object storage system compatible with Amazon S3 API. By integrating it with Authentik, we can leverage centralized authentication and role-based access control for our object storage environment.

Integration Overview

The integration between MinIO and Authentik involves the following components:

Configuring Grafana OAuth with Authentik

Wed, 19 Mar 2025 00:00:00 +0000

Introduction

Following our previous posts about setting up Authentik with Kubernetes and FluxCD and managing Authentik with Terraform, today we’ll demonstrate how to implement OAuth authentication for Grafana using Authentik as the identity provider. This integration offers several benefits:

Centralized user management with single sign-on (SSO)
Role-based access control for Grafana using Authentik groups
Secure authentication without the need to maintain separate user databases
Consistent user experience across services

Infrastructure Overview

Our setup consists of:

Managing Authentik with Terraform

Tue, 18 Mar 2025 00:00:00 +0000

Introduction

In my previous post, I detailed how to deploy Authentik on Kubernetes using FluxCD for GitOps-driven management. Today, I’ll explore how to manage the configuration of your Authentik instance using Terraform, providing a complete infrastructure-as-code solution for your identity provider.

Why Terraform for Authentik?

While deploying Authentik with Kubernetes and FluxCD gives us a solid foundation, we still need to configure the actual identity provider - creating applications, setting up OAuth providers, configuring authorization policies, and more. This is where Terraform comes in.

Setting up Authentik with Kubernetes and FluxCD

Mon, 17 Mar 2025 00:00:00 +0000

Introduction to Authentik

Authentik is a powerful open-source Identity Provider (IdP) that allows centralized management of user authentication, authorization, and single sign-on. In this post, I’ll walk through how I’ve set up Authentik in my Kubernetes cluster using FluxCD for GitOps-driven deployment.

Infrastructure Overview

I’m using a GitOps approach with FluxCD to manage my Kubernetes infrastructure. The configuration is maintained in a Git repository, ensuring that my entire setup is declarative and version-controlled.

Upgrading microk8s (snap) on Ubuntu

Mon, 01 Jul 2024 00:00:00 +0000

I have been using microk8s for a couple of years now. On my ubuntu system it’s installed as a snap and was stuck on v1.28. I was greeted with an error something similar to:

Hit:2 http://security.ubuntu.com/ubuntu jammy-security InRelease
Get:1 https://packages.cloud.google.com/apt kubernetes-xenial InRelease [8,993 B]
Err:1 https://packages.cloud.google.com/apt kubernetes-xenial InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B53DC80D13EDEF05
...

Here is how you can fix this:

Parsing with Pest

Thu, 16 Jun 2022 00:00:00 +0000

A couple of weeks ago I was working on datafusion-catalogprovider-glue, a catalogprovider for Datafusion sourcing from AWS Glue.

The AWS SDK for Rust returns an UTF-8 string as the datatype value for each column in a table. A crawler will use datatypes which are supported by Athena.

Parsing the initial data types was pretty simple:

match glue_type {
    "int" => Ok(DataType::Int32),
    "boolean" => Ok(DataType::Boolean),
    "bigint" => Ok(DataType::Int64),
    "float" => Ok(DataType::Float32),
    ...
}

Support for decimal and arrays remained simple with some regular expressions and recursion:

Notes on running (java) FlightSqlExample

Thu, 28 Apr 2022 00:00:00 +0000

Here are my notes on how to run the sample java Arrow Flight SQL server and client.

Clone https://github.com/apache/arrow/:

git clone git@github.com:apache/arrow.git

Install snapshot versions of arrow:

cd java
mvn clean install -DskipTests=true

Add Application entry point:

cd flight/flight-sql
cat << EOF > ./src/test/java/org/apache/arrow/flight/sql/example/Main.java
package org.apache.arrow.flight.sql.example;

import org.apache.arrow.flight.FlightServer;
import org.apache.arrow.flight.Location;
import org.apache.arrow.memory.BufferAllocator;
import org.apache.arrow.memory.RootAllocator;

public class Main {

    public static void main(String args[]) throws Exception {

        BufferAllocator allocator = new RootAllocator(Integer.MAX_VALUE);

        final String LOCALHOST = "localhost";

        final Location serverLocation = Location.forGrpcInsecure(LOCALHOST, 52358);
        final FlightServer server = FlightServer.builder(allocator, serverLocation, new FlightSqlExample(serverLocation))
                .build()
                .start();

        System.out.println("server is up and running at port: " + server.getPort());
        Thread.sleep(Long.MAX_VALUE);
    }
}
EOF

4. Run the server:

```bash
mvn test exec:java -Dcheckstyle.skip -DskipTests=true -Drat.skip=true -Dexec.mainClass="org.apache.arrow.flight.sql.example.Main" -Dexec.classpathScope="test"

Compile the client:

mvn compile -Dcheckstyle.skip -Drat.skip=true

Run client without arguments:

mvn exec:java -Dcheckstyle.skip -Drat.skip=true \
    -Dexec.mainClass="org.apache.arrow.flight.sql.example.FlightSqlClientDemoApp"

Output:

Notes on using grpc with rust and tonic

Thu, 28 Apr 2022 00:00:00 +0000

In the Tonic examples proto files are used to generated service and client stubs with tonic_build.

The Getting started section mentions the following:

For IntelliJ IDEA users, please refer to this and enable org.rust.cargo.evaluate.build.scripts experimental feature.

But in order to have a nice development experience you need some additional tweaks.

You can find the full code here: https://github.com/timvw/arrow-flightsql-odbc

By default the stubs are generated in ./target/…/build/… Unfortunately CLion does not scan those folders and you don’t get to benefit from intellisense.

Hosting a secure registry on microk8s

Mon, 08 Nov 2021 00:00:00 +0000

The documentation for microk8s seems to suggest that there is a built-in registry that can be used, but not in a secure way.

In essence, you need to configure the following:

Storage

For storage I will assume that the local filesystem is sufficient (or that you have a safety net, such as NFS backing it up, in place).

Authentication

For authentication I use create a secret which contains a htpasswd file, here is how you can generate this:

Notes on microk8s and cert-manager

Mon, 15 Mar 2021 00:00:00 +0000

Last couple of weeks I’ve been using MicroK8s for local development.

Installing current version of cert-manager just worked by following the installation instructions:

kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/v1.2.0/cert-manager.yaml

Then I enabled the ingress addon:

microk8s.enable ingress

Configuring Let’s Encrypt required some deviations from the documentation. Only resources of type ClusterIssuer and public as ingress class seem to work:

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-staging
spec:
  acme:
    email: tim@timvw.be
    server: https://acme-staging-v02.api.letsencrypt.org/directory
    privateKeySecretRef:
      name: letsencrypt-staging
    solvers:
    - http01:
        ingress:
          class: public
---
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: tim@timvw.be
    privateKeySecretRef:
      name: letsencrypt-prod
    solvers:
    - http01:
        ingress:
          class: public

When using nginx as ingress class I ran into various errors:

Use cases for Github Actions

Wed, 20 Jan 2021 00:00:00 +0000

These days many systems are built with Unix Philosophy in mind, but the applications are in the form of containers. How many malicious containers images would be out there? :)

Here are a couple of examples where I leveraged Github Actions to glue such applications:

Publishing this blog with HUGO

Frustrated with jekyll ndependency hell I decided to swith to HUGO. It’s fast, really fast. And does whatever I need it to do.

cluster-info on k8s cluster with limited permissions

Tue, 05 Jan 2021 00:00:00 +0000

When you have limited access (eg: only a specific namespace (~ openshift project) on a kubernetes cluster you may not be able to run kubectl cluster-info.

➜  ~ kubectl cluster-info

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
Error from server (Forbidden): services is forbidden: User "timvw" cannot list resource "services" in API group "" in the namespace "kube-system"

As soon as you run the command in your namespace it will work:

➜  ~ kubectl cluster-info -n spark
Kubernetes master is running at https://api.customer.example:443

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

Leverage Terraform to create virtual machine scaleset with spot instances

Wed, 09 Dec 2020 00:00:00 +0000

In a previous post I demonstrated how easy it has become to deploy a webapplications with an HTTPS backend on Kubernetes and Azure. Let’s expand this cluster with a node pool that is backed by spot instances:

resource "azurerm_kubernetes_cluster_node_pool" "spot" {
    name                  = "spot"
    kubernetes_cluster_id = azurerm_kubernetes_cluster.k8s.id
    vm_size         = "standard_D2s_v4"

    node_count      = 0
    enable_auto_scaling = true
    min_count = 0
    max_count = 5

    priority = "Spot"
    eviction_policy = "Delete"
    spot_max_price = 0.02

    tags       = var.tags
}

The nodes in this pool will be tainted with kubernetes.azure.com/scalesetpriority=spot:NoSchedule.

Leverage Terraform, NGINX Ingress Controller, cert-manager and Let's Encrypt to quickly create a Kubernetes cluster on AWS.

Tue, 25 Feb 2020 00:00:00 +0000

In my previous post I demonstrated how easy it has become to deploy a webapplications with an HTTPS backend on Kubernetes and Azure. In this post I demonstrate the same but on AWS.

In order to follow along you should clone the sample code from this repository:

git clone https://github.com/timvw/sample-terraform-aws-k8s-nginx-letsencrypt

First configure the aws access_key and secret_key for Terraform:

export AWS_ACCESS_KEY="XXXXXXXXXXXXXXXXXX"
export AWS_SECRET_KEY="XXXXXXXXXXXXXXXXXX"
export AWS_DEFAULT_REGION="eu-west-1"

With all this configuration in place we can instruct Terraform to create the kubernetes cluster:

Leverage Terraform, NGINX Ingress Controller, cert-manager and Let's Encrypt to quickly create a Kubernetes cluster which can serve webapps over HTTPS.

Mon, 10 Feb 2020 00:00:00 +0000

In this post I demonstrate how easy it has become to create a kubernetes cluster which serves webapplications over HTTPS.

In order to follow along you should clone the sample code from this repository:

git clone https://github.com/timvw/sample-terraform-azure-k8s-nginx-letsencrypt

First configure the azure service principal for Terraform:

export ARM_CLIENT_ID="XXXXX-XXXXX-XXXXX-XXXXX-XXXXX"
export ARM_CLIENT_SECRET="XXXXX-XXXXX-XXXXX-XXXXX-XXXXX"
export ARM_SUBSCRIPTION_ID="XXXXX-XXXXX-XXXXX-XXXXX-XXXXX"
export ARM_TENANT_ID="XXXXX-XXXXX-XXXXX-XXXXX-XXXXX"

The resources in this example depend on the following variables: client_id, client_secret, aks_service_principal_app_id and aks_service_principal_client_secret. One way to configure them is by exporting their values as a TF_VAR_xxx:

Looking back at 2016

Sat, 31 Dec 2016 00:00:00 +0000

Starting 2016 at Emergency Care was a game changer for me.

On a personal level I have successfully changed my diet and lost 45kg (BMI went from 50 to 35), completed Start2Run (0-5km/30min) and Continue2Run (5-10km/60min). Looking forward to loosing more weight and getting a BMI < 30 again. Finishing a 1/2 marathon would be awesome too. Had plenty of quality family time as well!

On a professional level I have changed focus from Enterprise Apps/.NET to Data intensive (Big Data, Augmented/Business Intelligence and a bit of Machine learning) mainly using Scala. Had some serious fun bringing a Kafka cluster in place as the central messaging interface in an industrial setting (24/7) continuously pushing > 1 million messages/sec. Became familiar with Docker and looking forward to see it replace Java Application Servers.

Parsing lines from Spark RDD

Sun, 20 Nov 2016 00:00:00 +0000

A typical Apache Spark application using RDD api starts as following:

val lines = sc.textFile("/path/to/data")
val records = lines.map(parseLineToRecord)

case class Record(...)

def parseLineToRecord(line: String) : Record = {
  val parts = line.split("\t", -1)
  ...
  Record(..)
}

In case of bad records you very often want to discard the unparseable lines:

def parseLineToRecordOption(line: String) = Option[Record] = {
  try {
    ...
    Some(Record(..))
  } catch {
    case _ => None
  }
}

val records = lines.map(parseLineToRecordOption).filter(x => x.isDefined).map(x => x.get)

And then you discover that you there is an implicit conversion from Option[T] to Iterable[T]. The nice thing is that you now can use flatMap instead of filter + map:

Blog migrated to Jekyll

Tue, 04 Oct 2016 00:00:00 +0000

As many other people I have decided to leave Wordpress behind and move to Jekyll instead.

Most posts have been migrated pretty well but I do not feel like bothering with them anymore. In fact, some of them have become irrelevant, some of them are just wrong and others only attract spammers. In summary: they are not worth my time anymore. In case you really loved them, you can still send a pull-request :P

Docker toolbox to the rescue

Sat, 01 Oct 2016 00:00:00 +0000

With the help of Docker Toolbox a lot of apps become easily available…

By default volumes can only be mapped on folders under the user home directory.

Here is how to enable mapping of the entire c-drive

#!/bin/sh
# script to expose c-drive to docker vm and docker containers
#
# stop the docker vm
docker-machine stop default
# share your windows c-drive with the docker (host) vm
/c/Program\ Files/Oracle/VirtualBox/VBoxManage.exe sharedfolder add default --name C_DRIVE --hostpath c:/
# start the docker (host) vm
docker-machine start default
# mount the c-drive in the docker (host) vm
docker-machine ssh default 'sudo chown docker /var/lib/boot2docker/profile && echo mount -t vboxsf C_DRIVE /c >> /var/lib/boot2docker/profile'

Examples

About maven dependency type 'bundle'

Fri, 29 Jan 2016 00:00:00 +0000

Earlier this week my build failed because maven was not able to resolve an (indirect) dependency on some package. It took me a while to notice that the dependency node in the pom file had an extra attribute: type = bundle. It only took a couple of minutes to find a good explanation here. Build fixed 😉

Composing functions and leveraging scala.util.Try

Fri, 29 Jan 2016 00:00:00 +0000

Last couple of days I have been hacking around trying to find a cute way to express the intent of my code. Typically it involves parsing some input, validating whatever rules that are in charge and persisting some values. In scala one can compose such a function by using the andThen method. Here is a concrete example:

def id(x: String) = x  
def parseInput = id _
def validate = id _
def persist = id _

def usecase1 = parseInput andThen validate andThen persist

Inspired by the excellent series on Railway Oriented Programming series by Scott Wlaschin I wanted to take advange of scala.util.Try to remove try/catch clutter from my code. With a little helper function I can now compose my usecase as following:

Using Gson to serialize Scala objects

Thu, 14 Jan 2016 00:00:00 +0000

gson is a pretty nice library that converts Java objects into JSON and back. When using this library from Scala things become a bit harder (eg: Plenty of people have difficulties when their scala object has an (im)mutable Map or List).

Here is an example to convert a JSON object to a Map[String,String]:

import com.google.gson.Gson
import scala.collection.JavaConversions._

val mapJson = "{ 'a': 'b', 'c': 'd' }"
val map = new Gson().fromJson(mapJson, classOf[java.util.Map[String, String]])

Now that we know that this works, we hide the java types in the constructor and expose a nicer scala type via a method:

Notes on running spark-notebook

Thu, 27 Aug 2015 00:00:00 +0000

These days Docker makes it extremely easy to get started with virtually any application you like. At first I was a bit skeptical but over the last couple of months I have changed my mind. Now I strongly believe this is a game changer. Even more when it comes to Windows. Anyway, these days kitematic (GUI to manage docker images) allows you to simply pick the spark-notebook by Andy Petrella.

Scaffolding scala projects

Wed, 19 Aug 2015 00:00:00 +0000

These days the cool kids scaffold their projects with Yeoman. Obviously I could not stay behind, so here is my first generator for scala.

ConcurrencyCheck with EF/Devart on Oracle

Fri, 20 Feb 2015 00:00:00 +0000

Earlier this week I was wondering how I could easily achieve optimistic concurrency in a system using EF/Devart targetting an Oracle database (Not really my preferred technologies, but whatever:P). Here is a potential solution:

Using a column for optimistic concurrency is documented on the devart website:

[Table("TEST")]
public class Test : IRequireConcurrencyCheck  
{
	...
	[Required]
	[Column("VERSION")]
	[ConcurrencyCheck] // TELL EF to use this column as our "timestamp/logical version"
	public virtual int Version { get; protected set; } // protected, so users of this type can not touch this (easily)
}

By introducing an interface that exposes a version number like below:

Failure to load mono-supplied .dylib (libgdiplus.dylib) when running from console

Sat, 27 Sep 2014 00:00:00 +0000

So earlier this week I was bit by the following bug: Bug 22140 – Failure to load mono-supplied .dylib when running from console.

The workaround that works for me is the following: Edit /Library/Frameworks/Mono.framework/Versions/3.8.0/etc/mono/config and

replace the entries for libgdiplus:

<dllmap dll="gdiplus" target="/Library/Frameworks/Mono.framework/Versions/3.8.0/lib/libgdiplus.dylib" os="!windows"/>
<dllmap dll="gdiplus.dll" target="/Library/Frameworks/Mono.framework/Versions/3.8.0/lib/libgdiplus.dylib" os="!windows"/>
<dllmap dll="gdi32" target="/Library/Frameworks/Mono.framework/Versions/3.8.0/lib/libgdiplus.dylib" os="!windows"/>
<dllmap dll="gdi32.dll" target="/Library/Frameworks/Mono.framework/Versions/3.8.0/lib/libgdiplus.dylib" os="!windows"/>

Deploying a Cloud Service to Azure with Octopus

Fri, 15 Aug 2014 00:00:00 +0000

Currently Octopus has limited support to deploy a Cloud Service on Azure. A typical use-case is that you need a different Web.Config file per environment. Simply add the Web.Environment.Config files to your NuGet package and use the following PreDeploy.ps1 script:

# Load unzip support
[Reflection.Assembly]::LoadWithPartialName("System.IO.Compression.FileSystem") | Out-Null
function Unzip($zipFile, $destination)
{
	If (Test-Path $destination){	  
		Remove-Item $destination -Recurse | Out-Null
	}
	  
	New-Item -ItemType directory -Force -Path $destination | Out-Null  
	[System.IO.Compression.ZipFile]::ExtractToDirectory($zipFile, $destination) | Out-Null
}

# Unzip deployment package  
$CsPkg = "Customer.Project.Api.Azure.cspkg"
Unzip $CsPkg "azurePackage"
Unzip (Get-Item (join-path -path "azurePackage" -childPath "*.cssx")) "website"

# Perform replacements, eg: replace Web.Config  
$ConfigFileToUse = "Web." + $OctopusParameters["Octopus.Environment.Name"] + ".config"
Copy-Item -Path $ConfigFileToUse -Destination "website/sitesroot/0/Web.Config" -Force

# Repackage  
$role = "Customer.Project.Api"
$contentPath = "website\approot"
$rolePath = "website/approot"
$webPath = "website/sitesroot/0"
$cspackPath = "C:\Program Files\Microsoft SDKs\Windows Azure\.NET SDK\v2.2\bin\cspack.exe"
& $cspackPath "ServiceDefinition.csdef" "/out:$CsPkg" "/role:$role;$rolePath;Customer.Project.Api.dll" "/sites:$role;Web;$webPath" "/sitePhysicalDirectories:$role;Web;$webPath"

Cute sort implementation

Mon, 28 Jul 2014 00:00:00 +0000

For years I had been implementing my sort functions as following:

(x,y) => {  
	if (x.PartName == null && y.PartName == null) return 0;
	if (x.PartName == null) return -1;
	if (y.PartName == null) return 1; 
	return x.PartName.CompareTo(y.PartName);
}

Earlier today I found the following cute variant while browsing through the ServiceStack codebase:

(x,y) => x.Priority - y.Priority

Clone all your repositories on another machine

Wed, 23 Apr 2014 00:00:00 +0000

Recently I was configuring a new machine (God, i love Chocolatey) and I wanted to take all the repositories I have under c:/src and clone them on my new machine. Here is how i did that:

# write all remote fetch locations into repositories.txt  
find /c/src -type d -mindepth 1 -maxdepth 1 -exec git -work-tree={} -git-dir={}/.git remote -v \; | grep fetch | awk '{print $2}' > repositories.txt

# clone each repository  
cat repositories.txt | xargs -l1 git clone

Or as a gist: https://gist.github.com/timvw/11208834.

A parameterized active pattern to match the first elements of an array

Thu, 30 Jan 2014 00:00:00 +0000

Been writing code in F# for almost a year and never blogged about it. Time to change that. Earlier today someone asked the following on twitter:

Is it possible to pattern match the first part of an array in #FSharp? Something like | 1::2::3::tail but for arrays? #lazyweb

I accepted the challenge :)

let (|Array|_|) pattern toMatch =      
	let patternLength = Array.length pattern
	let toMatchLength = Array.length toMatch
	let tailLength = toMatchLength - patternLength

	if patternLength > toMatchLength then
		None
	else
		let firstElementsAreEqual = [ 0 .. (patternLength - 1) ] |> Seq.forall (fun i -> pattern.[i] = toMatch.[i])
          
		if firstElementsAreEqual then
			Some(Array.sub toMatch patternLength tailLength)
		else 
			None
		
match [|1;2;3|] with
| Array \[|1|] tail -> sprintf "bingo %i" (tail |> Array.sum) // the tail is [|2;3|\]

Or as a gist: https://gist.github.com/timvw/8717796.

Comments are disabled on this blog

Thu, 23 Jan 2014 00:00:00 +0000

As of now comments are disabled on this blog. Want to reply? Write your own post and pingback or engage a conversation on twitter with @timvw.

The curious case of trailing spaces in SQL

Sat, 27 Apr 2013 00:00:00 +0000

A while ago I was quite surprised to see that the following query returns 1 instead of 0:

SELECT COUNT(*) WHERE N'Tim' = N'Tim '; -- notice the trailing space

Apparently this is just standard behaviour. Here is an extract from sql1992.txt (Section 8.2 Paragraph 3):

3) The comparison of two character strings is determined as fol-
            lows:

            a) If the length in characters of X is not equal to the length
              in characters of Y, then the shorter string is effectively
              replaced, for the purposes of comparison, with a copy of
              itself that has been extended to the length of the longer
              string by concatenation on the right of one or more pad char-
              acters, where the pad character is chosen based on CS. If
              CS has the NO PAD attribute, then the pad character is an
              implementation-dependent character different from any char-
              acter in the character set of X and Y that collates less
              than any string under CS. Otherwise, the pad character is a
              <space>.

            b) The result of the comparison of X and Y is given by the col-
              lating sequence CS.

            c) Depending on the collating sequence, two strings may com-
              pare as equal even if they are of different lengths or con-
              tain different sequences of characters. When the operations
              MAX, MIN, DISTINCT, references to a grouping column, and the
              UNION, EXCEPT, and INTERSECT operators refer to character
              strings, the specific value selected by these operations from
              a set of such equal values is implementation-dependent.

Sample query to demonstrate influence of collation in Sql Server

Thu, 18 Oct 2012 00:00:00 +0000

Lately I had the pleasure to investigate collations and here is a sample query that demonstrates how a collation impacts the behaviour of a query:

WITH [Words] AS (
	SELECT N'Een' AS [word]  
	UNION ALL  
	SELECT N'Eèn'	  
	UNION ALL
	SELECT N'EEN'
)
SELECT [word]	  
FROM [Words]  
WHERE [word]	  
--COLLATE Latin1_General_CS_AS -- returns Een
--COLLATE Latin1_General_CI_AI -- returns Een, Eèn and EEN
--COLLATE LAtin1_General_CI_AS -- returns Een and EEN
COLLATE Latin1_General_CS_AI -- returns Een and Eèn
= N'Een';

Copy all mp3 files in Music folder to USB dribe

Sat, 22 Sep 2012 00:00:00 +0000

Copying all mp3 files from my Music folder to a USB drive is pretty easy on my Macbook:

find Music -name *.mp3 -exec cp {} /Volumes/SANDISK \;

Using eID on OS X Mountain Lion

Mon, 06 Aug 2012 00:00:00 +0000

Last week or so I got myself a MacBook Air and I am really loving it so far. Today I needed to use my eID so I installed the middleware application without any hassle but had a hard time configuring Safari. Apparently Apply removed support for PKCS #11 in OS X Mountain Lion. After installing SmartCard Services the certificates appeared in the Keychain and I became able to authenticate on websites using my certificate

Add missing books to iTunes

Sun, 20 May 2012 00:00:00 +0000

These days i read most books on my ipad. The problem is that iTunes does not seem to add pdf files when i choose ‘Add Folder’ to the library. So here is a small application that adds them one by one (way too lazy/unmotivated to do this by hand).

https://gist.github.com/2759128

Multiclean solution

Thu, 26 Apr 2012 00:00:00 +0000

One of my favorite powershell commands when cleaning up:

$RootFolder = 'C:\tfs'
Get-ChildItem $RootFolder bin -Recurse | Remove-Item -Recurse
Get-ChildItem $RootFolder obj -Recurse | Remove-Item -Recurse

An example of Common Table Expression and Window function usage...

Tue, 27 Mar 2012 00:00:00 +0000

Earlier this week some colleague had been assigned a maintenance task and asked me how I would solve it. Every customer is permitted to have an amount of publications. All excess publications should be removed from the system (only the n most recent ones are permitted to remain on the system).

Here is an example of the Customer table:

CREATE TABLE [dbo].[Customer](  
	[CustomerId] [int] IDENTITY(1,1) NOT NULL, 
	[CustomerName] [nvarchar](50) NOT NULL,  
	[PermittedPublications] [int] NOT NULL
);

INSERT INTO [dbo].[Customer]		  
	([CustomerName], [PermittedPublications])
VALUES
	('timvw', 2),		  
	('mike', 3);

An example of the customer publications table:

Say no to primitives in your API.. and make your software more explicit

Fri, 28 Oct 2011 00:00:00 +0000

A while ago I wrote some code like this:

public interface ICanBroadcast
{ 
  public void Broadcast(string message) { ... }  
  public void Broadcast(string message, string author) { ... }
}

A bit later the requirements changed and from now on it was required to specify the topic:

public interface ICanBroadcast  
{
  public void Broadcast(string message, string topic) { ... }  
  public void Broadcast(string message, string author, string topic) { ... } 
}

In case you were using Broadcast(string message) the compiler would rightfully inform you that no such method exists. In case you were using Broadcast(string message, string author) the compiler does not catch the error and incorrectly uses the author as topic. I can only hope that you have a suite of tests that makes you notice that something is wrong when you upgrade to my latest release.

Force the removal of a file with PowerShell

Tue, 18 Oct 2011 00:00:00 +0000

Last couple of weeks I have been generating a lot of files (and restricting their ACLs) and today I decided to remove all those files. The problem is that my user account did not have permissions on those files. Here is a small script that will first take ownership of the file, then grants FullControl permissions, and finally removes the file 🙂

function RemoveFile 
{	  
	param($FileName)
	
	&takeown /F $FileName
	$User = [System.Security.Principal.WindowsIdentity]::GetCurrent().User
	$Acl = Get-Acl $FileName	  
	$Acl.SetOwner($User)	  
	$AccessRule = New-Object System.Security.AccessControl.FileSystemAccessRule($User, "FullControl", "Allow")	  
	$Acl.SetAccessRule($AccessRule)	  
	Set-Acl $FileName $Acl
	Remove-Item $FileName 
}

Get-ChildItem *.txt -R | % { RemoveFile $_.FullName; }

Edit on 2011-10-19

Remove all access rules from a directory

Thu, 22 Sep 2011 00:00:00 +0000

A while ago i needed to write some code that removes all (existing/inherited) access rules from a given directory. It was pretty frustrating to notice that all my attempts seemed to fail (RemoveAccessRule, PurgeAccessRule, …)

Finally i found that SetAccessRuleProtection was the method that i needed to invoke.

const string Folder = @"c:\temp\secured";
var directory = new DirectoryInfo(Folder);
var directorySecurity = directory.GetAccessControl();
directorySecurity.SetAccessRuleProtection(true,false);
directory.SetAccessControl(directorySecurity);

Image of the security properties tab in windows

Use SQL Server Profiler to see if a connection is pooled

Fri, 19 Aug 2011 00:00:00 +0000

It took me a couple of websearches to discover how i can see in SQL Server Profiler whether or not a connection is pooled. Apparently you have to check ‘Show all columns’ and then you can check the ‘EventSubClass’ column:

This is how it looks like in your trace window:

SqlConnectionStringBuilder sets the Pooling property to true by default

Thu, 18 Aug 2011 00:00:00 +0000

Here is something that surprised me: SqlConnectionStringBuilder sets the Pooling property to true by default.

Specialized solution for aggregate string concatenation

Mon, 01 Aug 2011 00:00:00 +0000

I have noticed that most people come up with the following solution to build a string in T-SQL:

WITH [Numbers] AS (	  
	SELECT TOP(10) [n]	  
	FROM [Nums] 
)	  
SELECT @message = COALESCE(@message, '') + '' + CAST([n] AS nvarchar(2))	  
FROM [Numbers];

SELECT @message = STUFF(@message, 1, 2, '');
SELECT @message;

Important! Microsoft has no official documentation describing this aggregate concatenation technique that is based on the assignment SELECT syntax. The behavior described here is based on observation alone. The current implementation of the ConcatOrders function doesn’t incorporate an ORDER BY clause and does not guarantee the order of concatenation. According to a blog entry by Microsoft’s Conor Cunningham, it seems that SQL Server will respect an ORDER BY clause if specified (http://blogs.msdn.com/sqltips/archive/2005/07/20/441053.aspx). Conor is a very credible source, but I should stress that besides this blog entry I haven’t found any official documentation describing how a multi-row assignment SELECT should behave—with or without an ORDER BY clause.

TryGetResult

Mon, 01 Aug 2011 00:00:00 +0000

I think this entry has been in the pipeline for a couple of years now and today i have decided to finally post it 😉 I got frustrated with the annoying out parameter in TryGet methods so i decided to use a different signature using TryGetResult:

public class TryGetResult<T> 
{
  public TryGetResult()   
  {   
    Success = false;  
  }

  public TryGetResult(T result)  
  {   
    Success = true; 
    Result = result;  
  }

  public bool Success { get; private set; }

  public T Result { get; private set; }
}

And now your TryGet methods can have the following signature:

Launch DtExec from PowerShell

Fri, 15 Jul 2011 00:00:00 +0000

Running an SSIS package from PowerShell (using DTExec) can be as simple as:

RunPackage -File 'C:\test.dtsx' -DatabaseHost '.' -DatabaseName 'TEST';

Here are the functions that make it this simple:

function GetDtExecPath {    
  $DtsPath = (Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Microsoft SQL Server\100\DTS\Setup').SQLPath;    
  $DtExecPath = (Resolve-Path "$DtsPath\Binn\DTExec.exe");    
  $DtExecPath;
}

function GetDtExecPropertyPathValue() {      
  param(
    $PropertyPath = '',
    $Value = '';
  );

  "$PropertyPath;\`"\`"$Value\`"\`"";
}

function RunPackage {
      
  param(        
  $DtExecPath = (GetDtExecPath),       
  $File = 'test.dtsx'  
  );

  $Params = "/FILE $File";
   
  for($i = 0; $i -lt $Args.Length; $i += 2) {       
    $PropertyPath = $Args[$i].SubString(1);       
    $Value = $Args[$i+1];       
    $PropertyPathValue = GetDtExecPropertyPathValue -PropertyPath $PropertyPath -Value $Value;       
    $Params += " /SET $PropertyPathValue";    
  } 

  &"$DtExecPath" $Params;
}

Building a Nums table (quickly)

Wed, 13 Jul 2011 00:00:00 +0000

A while ago i presented my approach to generate a nums table here.

DECLARE @count INT = 1000;

WITH    
  [Nums1] AS ( SELECT 1 AS [Value] UNION SELECT 2 AS [Value] ) 
, [Nums2] AS ( SELECT A.* FROM [Nums1] AS A, [Nums1] AS B, [Nums1] AS C)  
, [Nums3] AS ( SELECT A.* FROM [Nums2] AS A, [Nums2] AS B, [Nums2] AS C)
, [Nums4] AS ( SELECT A.* FROM [Nums3] AS A, [Nums3] AS B )
, [Numbers] AS ( SELECT TOP(@count) -1 + ROW_NUMBER() OVER(ORDER BY [Value]) AS [Value] FROM[Nums4] )
  
SELECT * FROM [Numbers];

Because we only use this code once to fill the table we don’t really care that it is not very fast. Today i discovered there is a way to speed it up in this wonderful book: Inside Microsoft® SQL Server® 2008: T-SQL Querying:

Using User-Defined Table Type with Identity column in ADO.NET

Wed, 13 Jul 2011 00:00:00 +0000

A while ago i wanted to use a User-Defined Table Type to pass in a set of records. Nothing special about this except that the first column of the UDTT was an Identity column:

CREATE TYPE [Star].[example] AS TABLE(  
  [Ordinal] [int] IDENTITY(1,1) NOT NULL,  
  [Name] [nvarchar](200) NOT NULL,
)

After finding a lot of posts saying that this is not supported a colleague of mine, Stephen Horsfield, found a way to do it as following:

Set variables in SSIS package at runtime

Thu, 19 May 2011 00:00:00 +0000

The documentation on dtexec Utility (SSIS Tool) says the following:

/Set propertyPath;value

(Optional). Overrides the configuration of a variable, property, container, log provider, Foreach enumerator, or connection within a package. When this option is used, /Set changes the propertyPath argument to the value specified. Multiple /Set options can be specified.

At first sight this works like a charm but as soon as your value has a space dtexec seems to get confused 🙁 It took me a couple of websearches to find a post that suggests the following:

How to handle (short) bursts of work

Mon, 09 May 2011 00:00:00 +0000

Here is a summary of how businesses around me handle short bursts of work:

When i go to the doctor:
- find an empty seat in the waiting room
- observe who’s before me
- wait untill all those people have been seen by the doctor
When i go to the supermarket:
- join the queue at the end
- wait untill al before me have been helped
When i go the the bakery:
- get a number from a ticketing machine at the entrance
- wait untill a seller indicates he’s willing to process my requests
When i go to my car dealer:

Invoke parameterized stored procedure with PowerShell

Mon, 21 Mar 2011 00:00:00 +0000

Here is a quick snippet that demonstrates how you can invoke a parametrized stored procedure with PowerShell:

$CreateTraceCommand = $SqlConnection.CreateCommand();
$CreateTraceCommand.CommandType = [System.Data.CommandType] "StoredProcedure";
$CreateTraceCommand.CommandText = "sp_trace_create";
$TraceIdParameter = $CreateTraceCommand.Parameters.Add("@traceid", [System.Data.SqlDbType] "Int");
$TraceIdParameter.Direction = [System.Data.ParameterDirection] "Output";
$OptionParameter = $CreateTraceCommand.Parameters.Add("@options", [System.Data.SqlDbType] "Int");
$OptionParameter.Value = [int] 2;
$TraceFileParameter = $CreateTraceCommand.Parameters.Add("@tracefile", [System.Data.SqlDbType] "NVarChar");
$TraceFileParameter.Value = [string] "c:\temp\test";

[void] $CreateTraceCommand.ExecuteNonQuery();

$TraceId = $TraceIdParameter.Value;
Write-Host "You created a trace with ```

Global hotkeys for iTunes on windows

Wed, 16 Mar 2011 00:00:00 +0000

These days i use iTunes as media player. Unlike winamp this program does not seem to support system-wide hotkeys to control playback. This is the place where a productivity tool like AutoHotkey comes into the rescue ;).

I have configured the following keys:

Move to next song: [Ctrl] + [Alt] + [Right]
Move to previous song: [Ctrl] + [Alt] + [Left]
Toggle play/pause: [Ctrl] + [Alt] + p
Turn volume up: [Ctrl] + [Alt] + [Up]
Turn volume down: [Ctrl] + [Alt] + [Down]

^!right::
DetectHiddenWindows , On
ControlSend , ahk_parent, ^{right}, iTunes ahk_class iTunes 
DetectHiddenWindows , Off
return

^!left:: 
DetectHiddenWindows , On
ControlSend , ahk_parent, ^{left}, iTunes ahk_class iTunes
DetectHiddenWindows , Off
return

^!p:: 
DetectHiddenWindows , On 
ControlSend , ahk_parent, {space}, iTunes ahk_class iTunes
DetectHiddenWindows , Off
return

^!up::
DetectHiddenWindows , On
ControlSend, ahk_parent, ^{UP}, iTunes ahk_class iTunes
DetectHiddenWindows , Off
return

^!down::
DetectHiddenWindows , On
ControlSend, ahk_parent, ^{DOWN}, iTunes ahk_class iTunes
DetectHiddenWindows , Off 
return

Navigation to the webpage was canceled

Wed, 16 Mar 2011 00:00:00 +0000

Earlier today i ran into the ‘Navigation to the webpage was canceled’ when i tried to open a CHM file:

Navigating to the file properties allows me to unblock the file:

And now i can happily use the CHM file:

Consume locally build software without overloading your $PATH

Sat, 12 Mar 2011 00:00:00 +0000

How do you consume locally build software? For a while now i have used the following approach:

Create a ~/bin folder
Add that ~/bin folder to my $PATH
Add symlinks from binary to ~/bin (ln -s ~/src/git-tfs/GitTfs.Vs2010/bin/debug/git-tfs.exe git-tfs)

Please let me know about your strategy..

Dynamic scriptblock with PowerShell

Sat, 12 Mar 2011 00:00:00 +0000

Earlier this week i tried to run a command on a remote computer but it did not seem to work:

$name = 'tim'
$computer = 'localhost'
Invoke-Command -ComputerName $computer -ScriptBlock { Write-Host "Hello $name" }

Because powershell serialises the { Write-Host “Hello $name” } as a string this ends up at the remote computer as { Write-Host “Hello $null” }. In order to send our “dynamic"command string over the wire we have to make sure it is serialised correctly:

Some PowerShell functions to work with SSIS packages

Sat, 12 Mar 2011 00:00:00 +0000

Here are some powershell functions (using XPath) that come in handy when working with SSIS packages:

function FindConnectionManagerNames {	  
	param($fileName)

	$xml = [xml] (Get-Content $fileName);	  
	$ns = New-Object Xml.XmlNamespaceManager $xml.NameTable;	  
	$ns.AddNamespace("DTS", "www.microsoft.com/SqlServer/Dts");	  
	$xml.SelectNodes("//DTS:ConnectionManager/DTS:Property[@DTS:Name='ObjectName']", $ns) | Foreach { $_."#text"; }

}

function GetConnectionManagerConnectionString {  
	param($fileName, $connectionManagerName)

	$xml = [xml] (Get-Content $fileName);
	$ns = New-Object Xml.XmlNamespaceManager $xml.NameTable;
	$ns.AddNamespace("DTS", "www.microsoft.com/SqlServer/Dts");
	$path = "//DTS:ConnectionManager[DTS:Property='$connectionManagerName']/DTS:ObjectData/DTS:ConnectionManager/DTS:Property[@DTS:Name='ConnectionString']"
	$xml.SelectSingleNode($path, $ns)."#text";
}

function FindVariables {	  
	param($fileName)

	$xml = [xml] (Get-Content $fileName);
	$ns = New-Object Xml.XmlNamespaceManager $xml.NameTable;
	$ns.AddNamespace("DTS", "www.microsoft.com/SqlServer/Dts");
	$xml.SelectNodes("//DTS:Variable/DTS:Property[@DTS:Name='ObjectName']", $ns) | Foreach { $_."#text"; }
}

function GetVariable {	  
	param($fileName, $variableName)

	$xml = [xml] (Get-Content $fileName);
	$ns = New-Object Xml.XmlNamespaceManager $xml.NameTable;
	$ns.AddNamespace("DTS", "www.microsoft.com/SqlServer/Dts");
	$xml.SelectSingleNode("//DTS:Variable[DTS:Property='$variableName']/DTS:VariableValue", $ns)."#text";
}

Some tips for .Net developers using git on cygwin

Sat, 12 Mar 2011 00:00:00 +0000

Here are some tips that i want to share with fellow .Net developers that use git on cygwin.

First of all i defined some aliases in my ~/.bashrc:

# open explorer in the current working directory 
alias explorer='explorer.exe "\`cygpath -aw \"$PWD\"\`"'

# invoke MSBuild
alias msbuild='/cygdrive/c/Windows/Microsoft.NET/Framework/v4.0.30319/MSBuild.exe&'

Because i do not like the TFS source control story i use git-tfs. As a .Net developer you want to add the following to your .git/info/exclude file:

Using WinMerge as difftool on cygwin/git

Sat, 12 Mar 2011 00:00:00 +0000

Last couple of weeks i have been using Git on cygwin and i got very satisfying results out of it. One thing that i wanted to tweak was the ability to use WinMerge to compare files. Here is how i do it:

Here is my ~/.gitconfig:

[user]	  
name = Tim Van Wassenhove	  
email = git@timvw.be
[diff]
external = "~/bin/git-diff-wrapper.sh"

Here is my ~/bin/git-diff-wrapper.sh (it uses cygpath to translate the paths):

#!/bin/sh
"/cygdrive/c/Program Files/WinMerge/WinMergeU.EXE" /e /ub /dl other /dr local "\`cygpath -aw $1\`" "\`cygpath -aw $2\`" "\`cygpath -aw $5\`"

And now we are good to go 😉

Get/SetVariable value from SSIS VariableDispenser

Tue, 08 Mar 2011 00:00:00 +0000

Here is some code that allows you to Get/Set a variable (object) value from/on the VariableDispenser in an SSIS package:

public static T GetVariable<T>(this VariableDispenser variableDispenser, string scopedVariableName)
{
  Variables variables = null;

  try
  {
    variableDispenser.LockForRead(scopedVariableName);
    variableDispenser.GetVariables(ref variables);
    return (T)variables[0].Value;
  }
  finally
  {
    if (variables != null) variables.Unlock();
  }
}

public static void SetVariable<T>(this VariableDispenser variableDispenser, string scopedVariableName, T value)
{
  Variables variables = null;

  try   
  {  
    variableDispenser.LockForWrite(scopedVariableName);  
    variableDispenser.GetVariables(ref variables);  
    variables[0].Value = value;  
  }  
  finally  
  {   
    if (variables != null) variables.Unlock();  
  }
}

Consume custom SSIS tasks without GAC installation

Sat, 05 Mar 2011 00:00:00 +0000

For a while i thought that in order to consume a custom SSIS task you had to install the assembly in the GAC. Now i know better 😉

For the designer (BIDS) you have to copy the files to

C:\Program Files\Microsoft SQL Server\100\DTS\Tasks
C:\Program Files\Microsoft SQL Server\100\DTS\PipelineComponents

For the runtime (BIDS) you have to copy the files to

C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies

And for dtexec you have to copy the files to

Exploring messaging at lower levels...

Sat, 26 Feb 2011 00:00:00 +0000

Yesterday a colleague of mine, Neil Robbins, asked me how a piece of code would look like if I apply the Hollywood principle on it (Don’t call us, we’ll cal you).

Let me start with setting the scene: The purpose of the code is to provide items via provider and to consume those items via a consumer.

Here is how my oldskool function signatures would look like:

class ItemProviderFactory {
  public ItemProvider Create() { .. } 
}

class ItemProvider {   
  public IEnumerable<Item> Provide() { .. } 
}

class ItemConsumerFactory { 
  public ItemConsumer Create() { .. }
}

class ItemConsumer { 
  public void Consume(IEnumerable<Item> items) { .. }
}

My Hollywood style function signatures look like the following:

Get current file in PowerShell

Mon, 24 Jan 2011 00:00:00 +0000

A while ago i wrote a small script to take care of deployment. Configuring the source folders went as following:

param(  
  $BaseDir = (Get-Location).Path,  
  $WebDir = (Resolve-Path "$BaseDir\web"),  
  $DatabaseDir = (Resolve-Path "$BaseDir\database")
)

The problem with this code is that it only works when your current working directory is set to the location of this script. An administrator (or build system) invokes the script as following:

PS C:\Users\Admin>& 'D:\Deployments\20110124\Deploy.ps1';

Because we don’t want to annoy the consumer of our script with the burden of making sure he is in the correct directory we modified our code as following:

Polling the existence of a file with PowerShell

Mon, 24 Jan 2011 00:00:00 +0000

Sometimes you run into a situations where a given task spawns a separate thread and completes it’s work on that separate thread. Eg: sending a bit XMLA to SQL Server Analysis Services with Microsoft.AnalysisServices.Deployment.exe and then waiting for the processing to be completed. Anyway, here is a simple function that will wait untill a given file exists:

function WaitForFile($File) {
  while(!(Test-Path $File)) {    
    Start-Sleep -s 10;   
  }  
}

Get entire message body from an Intent

Thu, 06 Jan 2011 00:00:00 +0000

I recently started programming the Android and noticed that most examples for processing an incoming SMS are not entirely correct.

An SMS message is limited to 160 characters. Current mobile phones break up a larger message in multiple messages transparently for the user. When Android notifies you about an incoming SMS it has all parts (of that large message) available. So here is how you reconstruct the entire message body from an Intent

Techniques learned in SQLtopia: Look Ma, no loops!

Sat, 11 Dec 2010 00:00:00 +0000

I have been programming in c-based languages for more than 10 years now. Lately i have spent quite a bit of time in SQLtopia and learned a couple of techniques that are quite different from what i was used to.

Let me explain with an example: The boss comes in and asks for a report that contains all the days on which i have worked this year. As a typical c# programmer i come up with the following solution: Iterate over all the days in the year and skip the days i was out on holidays:

Exploring window functions

Fri, 10 Dec 2010 00:00:00 +0000

Here is a sample query that allows you to explore the behavior of various aggregate window functions:

WITH    
  [Nums1] AS ( SELECT 1 AS [Value] UNION SELECT 2 AS [Value] )  
, [Nums2] AS ( SELECT A.* FROM [Nums1] AS A, [Nums1] AS B, [Nums1] AS C)  
, [Nums3] AS ( SELECT A.* FROM [Nums2] AS A, [Nums2] AS B, [Nums2] AS C)
, [Nums4] AS ( SELECT A.* FROM [Nums3] AS A, [Nums3] AS B )
-- Build numbers from 1 to 1000
, [Numbers] AS ( SELECT TOP(1000) ROW_NUMBER() OVER(ORDER BY [Value]) AS [Value] FROM[Nums4] )

SELECT    
  [Value]  
, ROW_NUMBER() OVER(PARTITION BY [Value] / 100 ORDER BY [Value] % 10) AS [RowNumber]
, RANK() OVER(PARTITION BY [Value] / 100 ORDER BY [Value] % 10) AS [Rank]
, DENSE_RANK() OVER (PARTITION BY [Value] / 100 ORDER BY [Value] % 10) AS [DenseRank]    
, NTILE(4) OVER (PARTITION BY [Value] / 100 ORDER BY [Value] % 10) AS [Tile100]  
FROM    
  [Numbers]
ORDER BY    
  [Value];

Convert AAC/M4A files to MP3 with VLC and PowerShell

Sat, 20 Nov 2010 00:00:00 +0000

Here is a way to convert your AAC/M4A files to MP3 using VLC media player:

vlc.exe -I dummy old.m4a :sout=#transcode{acodec=$codec,vcodec=dummy}:standard{access=file,mux=raw,dst=new.mp3} vlc://quit

Let’s wrap this command in a bit of PowerShell:

function ConvertToMp3([switch] $inputObject, [string] $vlc = 'C:\Program Files\VideoLAN\VLC\vlc.exe') {      
  PROCESS {            
    $codec = 'mp3';        
    $oldFile = $_;

    $newFile = $oldFile.FullName.Replace($oldFile.Extension, ".$codec");

    &"$vlc" -I dummy "$oldFile" ":sout=#transcode{acodec=$codec,vcodec=dummy}:standard{access=file,mux=raw,dst=\`'$newFile\`'}" vlc://quit | out-null;

    #Only remove source files when you are sure that the conversion works as you want          
    #Remove-Item $oldFile;
  }  
}

And now we can use this function for *all* m4a files in a given folder:

Configure Visual Studio 2010 environment in PowerShell

Wed, 17 Nov 2010 00:00:00 +0000

Instead of using the “Visual Studo Command Prompt (2010)” i wanted to use PowerShell instead. I found this post which does it for VS2008. Extending it for VS2010 was pretty easy:

function SetVS2008()
{
	$vs90comntools = (Get-ChildItem env:VS90COMNTOOLS).Value
	$batchFile = [System.IO.Path]::Combine($vs90comntools, "vsvars32.bat")
	Get-Batchfile $BatchFile
	[System.Console]::Title = "Visual Studio 2008 Windows PowerShell"
}

function SetVS2010()
{
	$vs100comntools = (Get-ChildItem env:VS100COMNTOOLS).Value
	$batchFile = [System.IO.Path]::Combine($vs100comntools, "vsvars32.bat")
	Get-Batchfile $BatchFile
	[System.Console]::Title = "Visual Studio 2010 Windows PowerShell"
}

function Get-Batchfile($file)
{
	$cmd = "\`"$file\`" & set"
	cmd /c $cmd | Foreach-Object {
		$p, $v = $_.split('=')
		Set-Item -path env:$p -value $v
	}
}

Load all script files at PowerShell startup

Wed, 17 Nov 2010 00:00:00 +0000

These days i have quite some scripts files that i want to be loaded each time i launch PowerShell. Windows PowerShell Profiles teaches me where i should store my $profile. Here is what it looks like:

# Lookup powershell scripts location
$UserProfile = (Get-ChildItem Env:UserProfile).Value;
$ScriptFolder = "$UserProfile\My documents\WindowsPowerShell";

# Source all .ps1 files in PowerShell profile folder  
Get-ChildItem $ScriptFolder -name -include '*.ps1' -exclude 'profile.ps1'   
| foreach { (. "$ScriptFolder\$_") };

# Configure environment for VS2010  
SetVS2010;

Get variable value from variable with PowerShell

Thu, 11 Nov 2010 00:00:00 +0000

Sometimes you only know at runtime in which variable a certain value is stored. Let me clarify with an example:

$tim = 30;
$evy = 24;
$name = Read-Host "Enter your name";

In essence, if $name equals tim we want to use $tim and if $name equals evy we want to use $evy. This can be achieved with Get-Variable:

$age = Get-Variable $name -valueOnly;
Write-Host "Your age is $age";

Update ConfigurationStrings in SSIS package with PowerShell

Thu, 11 Nov 2010 00:00:00 +0000

Here are some functions that allow you to update ConfigurationStrings in a SSIS package (dtsx) using PowerShell:

function UpdateConfigurationStrings($file)
{
	$xml = [xml] (Get-Content $file);
	$ns = New-Object Xml.XmlNamespaceManager $xml.NameTable;
	$ns.AddNamespace("DTS", "www.microsoft.com/SqlServer/Dts");
	UpdateConfigurationNodes $xml $ns;
	Set-Content $file $xml.OuterXml;
}

function UpdateConfigurationNodes($xml, $ns)
{
	$selectConfigurationNodes = "//DTS:Configuration";
	$xml.SelectNodes($selectConfigurationNodes, $ns) | foreach { UpdateConfigurationNode $_ $ns; };
}

function UpdateConfigurationNode($configurationNode, $ns)
{
	$selectConfigurationString = "./DTS:Property[@DTS:Name='ConfigurationString']";
	$configurationStringNode = $configurationNode.SelectSingleNode($selectConfigurationString, $ns);

	$oldConfigurationStringValue = $configurationStringNode.'#text';
	$newConfigurationStringValue = GetNewConfigurationStringValue $oldConfigurationStringValue;
	$configurationStringNode.'#text' = "$newConfigurationStringValue";
}

function GetNewConfigurationStringValue($oldConfigurationStringValue)
{
	# implement some logic to determine new value
	return "new value";
}

Build your solution with Visual Studio from MSBuild

Sun, 07 Nov 2010 00:00:00 +0000

Unfortunately MSBuild and BIDS Helper are not able to build an .asdatabase from our Analysis Services project (.dwproj). Here is a task which invokes Visual Studio to build such a solution:

<Target Name="DevEnvBuild">
	<Error Condition="'$(SolutionFile)'=="" Text="Missing SolutionFile" />
	<PropertyGroup>
		<DevEnvTool Condition="'$(DevEnvTool)'=="">C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\devenv.exe</DevEnvTool>
		<DevEnvSwitch Condition="'$(DevEnvSwitch)'=="">Build</DevEnvSwitch>
		<DevEnvBuildCommand>"$(DevEnvTool)" "$(SolutionFile)" /$(DevEnvSwitch)</DevEnvBuildCommand>
	</PropertyGroup>
	<Exec Command="$(DevEnvBuildCommand)" />
</Target>

Invoke PowerShell script from MSBuild

Sun, 07 Nov 2010 00:00:00 +0000

Here is a small MSBuild target that allows you to invoke a PowerShell script, eg: powershell.exe & ‘script.ps1’ -SomeParam ‘x’

<Target Name="InvokePowerShell">
	<PropertyGroup>
		<PowerShellCommand>"$(PowerShellTool)" "& '$(ScriptFile)' -SomeParam '$(SomeParam)' "</PowerShellCommand>
	</PropertyGroup>
	<Exec Command="$(PowerShellCommand)" />
</Target>

Modify a text file with PowerShell

Sun, 07 Nov 2010 00:00:00 +0000

A while ago i wanted to update a connection string in a configuration file. My first attempt was the following:

Get-Content $File
| Foreach { $_ -Replace "Source>(.*?)<", "Source>$New<" }
| Set-Content $File;

Running this scripts leads to the following error: “Set-Content : The process cannot access the file because it is being used by another process.” In order to avoid this you can complete the read operation before you start writing as following:

(Get-Content $File)
| Foreach { $_ -Replace "Source>(.*?)<", "Source>$New<" }
| Set-Content $File;

Deploying a Database Project does not create artefacts for custom schemas

Mon, 01 Nov 2010 00:00:00 +0000

Last week we noticed that the artefacts for a custom schema in our Database Project were not created (or updated). It took us a while to figure out what was wrong. When you add a script via the ‘Add Existing item’ menu in VS2010 the file’s Build Action is set to Not in Build for some unknown reason. As soon as we changed the value to Build and Deployed again our artefacts were created.

Update all repositories with Powershell

Mon, 25 Oct 2010 00:00:00 +0000

I typically store the repositories i am working on under D:\Code. Each morning i had to right click on each of those folders and select ‘SVN Update’ using Tortoise SVN. Today i decided there had to be a better way to accomplish this tedious task:

dir d:\code | foreach { svn update $_.FullName }

And in case you really like tortoise, you can do the following:

dir c:\code | foreach { tortoiseproc /command:update /closeonend:1 /path:$($_.FullName) }

T-SQL: Remove all rows from all tables in your schema

Tue, 07 Sep 2010 00:00:00 +0000

Sometimes i want to quickly clean up a database and start from fresh. Here is a small script that does exactly that.. (I just run the script a couple of times, untill no affected rows remain… Far more efficient than figuring out which constraints exist, building up a dependency tree, and cleanly deleting all rows):

-- Remove all rows from all tables
DECLARE @tableName VARCHAR(255)
DECLARE tableNames CURSOR FOR SELECT name FROM sys.Tables;

OPEN tableNames
FETCH NEXT FROM tableNames INTO @tableName
WHILE @@FETCH_STATUS = 0 
BEGIN
	EXEC('DELETE FROM [' + @tableName + ']')
	FETCH NEXT FROM tableNames INTO @tableName
END
CLOSE tableNames
DEALLOCATE tableNames

WIF: whr parameter is a hint for user Home Realm

Tue, 07 Sep 2010 00:00:00 +0000

Yesterday i was reading the Claims Based Identity & Access Control Guide and learned that the whr parameter is a hint from the application to the STS about the user’s STS. So if i look back at the code in WIF: Change STS per request i should not hardcode the HomeRealm parameter to timvw but use the company name instead.

string GetRedirectUrl(string company, string companySts, string realm, string returnUrl)
{
	var signInRequestMessage = new SignInRequestMessage(new Uri(companySts), realm)
	{
	Context = returnUrl,
	HomeRealm = company
	};

	return signInRequestMessage.WriteQueryString();
}

WIF: Change STS per request

Sun, 05 Sep 2010 00:00:00 +0000

Here is some code that will redirect unauthenticated users to their respective STS (Eg: A user visiting ~/CompanyA/Default.aspx will be asked to authenticate at the STS linked to CompanyA.

Notice that in the enterprise you typically have multiple applications that require this kind of behavior, so you would solve this by establishing trust between your app(s) and your STS + establish trust between your STS and the client STSes.)

public class Global : HttpApplication
{
	protected void wSFederationAuthenticationModule_RedirectingToIdentityProvider(object sender, RedirectingToIdentityProviderEventArgs e)
	{
		e.Cancel = true;
		RedirectToCompanySts();
	}

	void RedirectToCompanySts()
	{
		var httpContext = HttpContext.Current;
		var rawUrl = httpContext.Request.RawUrl;

		var returnUrl = rawUrl;
		var companyName = ExtractCompanyName(rawUrl);
		var companySts = GetCompanySts(companyName);
		var realm = GetRealm(companyName);
		var redirectUrl = GetRedirectUrl(companySts, realm, returnUrl);

		httpContext.Response.Redirect(redirectUrl, false);
		httpContext.ApplicationInstance.CompleteRequest();
	}

	string ExtractCompanyName(string rawUrl)
	{
		var regex = @"~/(.\*?)/.\*";
		var relativeUrl = VirtualPathUtility.ToAppRelative(rawUrl);
		var match = Regex.Match(relativeUrl, regex);
		return match.Success ? match.Groups[1].Value : "";
	}

	string GetCompanySts(string companyName)
	{
		if (companyName == "CompanyA") return @"http://localhost/STS2Site";
		return @"http://localhost/STSSite";
	}

	string GetRealm(string companyName)
	{
		var realm = @"http://localhost/RPSite/";
		if (!string.IsNullOrEmpty(companyName)) realm += companyName +"/";
		return realm;
	}

	string GetRedirectUrl(string companySts, string realm, string returnUrl)
	{
		var signInRequestMessage = new SignInRequestMessage(new Uri(companySts), realm)
		{
			Context = returnUrl,
			HomeRealm = "timvw"
		};

		return signInRequestMessage.WriteQueryString();
	}
}

Making the TemplateFileTask easier to use...

Wed, 25 Aug 2010 00:00:00 +0000

One of the disadvantages of the TemplateFile task (msbuildtasks) is the fact that it requires a lot of typing to define template values

<ItemGroup Condition= " '$(ConfigurationEnvironment)'=='build' ">
	<Tokens Include="a">
		<ReplacementValue>localhost</ReplacementValue>
	</Tokens>
	<Tokens Include="b">
		<ReplacementValue><mynode/></ReplacementValue>
	</Tokens>
</ItemGroup>

Here is a format proposition to make this a lot more finger friendly

<configuration>
	<variables env="build">
		<x name="a">localhost</x>
		<x name="b><mynode/></x>
	</variables>
</configuration>

Here is the msbuild script we need to achieve that

<PropertyGroup>
	<ConfigurationFile>configuration.xml</ConfigurationFile>
	<ConfigurationEnvironment>build</ConfigurationEnvironment>
</PropertyGroup>

<!-- Retreive all template values for the specific environment -->
<XmlQuery XmlFileName="$(ConfigurationFile)" XPath = "//variables[@env='$(ConfigurationEnvironment)']/*">
	<Output TaskParameter="Values" ItemName="Values" />
</XmlQuery>

<-- Construct @Tokens -->
<ItemGroup>
	<Tokens Include="%(Values.name)">
		<ReplacementValue>%(Values._innerxml)</ReplacementValue>
	</Tokens>
</ItemGroup>

<!-- Generate the configuration files -->
<Message Text="Available variables:" />
<Message Text="====================" />
<Message Text="%(Tokens.Identity): %(Tokens.ReplacementValue)" />

Happy coding!

What i dislike about the Web.config Transformation in VS2010

Wed, 25 Aug 2010 00:00:00 +0000

There are a couple of things that i strongly dislike about the Web.config transformation in VS2010

Only works with XML files (eg: Can’t be used to generate a release notes.txt file)
~~Does not seem to support externalized sections, eg: log4net.config in a separate file~~
~~No support to copy/paste transform files~~
Only works when Visual Studio 2010 is installed (And i am still not convinced a build server should have this).
Ties environment to build configuration

Lesson learned: Don’t trust your co-workers, always double-check!

Clean TemplateFile hack

Tue, 17 Aug 2010 00:00:00 +0000

A while ago i wrote about a Clever TemplateFile hack to use some xml block as ReplacementValue. Today i realized there is a clean way to achieve this by defining the value as CDATA

<TemplateTokens Include="mex">
	<ReplacementValue>
		<![CDATA[<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />]]>
	</ReplacementValue>
</TemplateTokens>

Behind Closed Doors: Secrets of Great Management

Thu, 29 Jul 2010 00:00:00 +0000

Behind Closed Doors: Secrets of Great Management first let’s you look behind the closed doors of all those private meetings and then provides you a set of techniques that allow you to be(come) a better manager. All 160 pages were worth reading!

Ship It!: A Practical Guide to Successful Software Projects

Thu, 29 Jul 2010 00:00:00 +0000

Ship It!: A Practical Guide to Successful Software Projects is focussed on one core idea: “The List”. The place in which you track your (and your teams) to-do and done work. I do not agree with everything written in the book but would still want to recommend it.

Brownfield Application Development in .NET

Thu, 22 Jul 2010 00:00:00 +0000

Brownfield Application Development in .NET is one of the better books i have read recently. The first part is about the ecosystem (version control, automated build, continuous integration, testing, defect management, … ), the second part is about the code (OO-principles, layering, dependencies, ui patterns, …) and the last chapter talks about ways to maintain the momentum. Very much recommended!

Quick reminder about the workings of Type.IsAssignableFrom

Wed, 21 Jul 2010 00:00:00 +0000

Here is a quick reminder about the workings of Type.IsAssignableFrom

class Fruit {}
class Banana : Fruit {}

[Test]
public void CanAssignBananaToFruit()
{
	var fruit = typeof (Fruit);
	var banana = typeof (Banana);
	Assert.IsTrue(fruit.IsAssignableFrom(banana));
}

[Test]
public void CanNotAssignFruitToBanana()
{
	var fruit = typeof(Fruit);
	var banana = typeof(Banana);
	Assert.IsFalse(banana.IsAssignableFrom(fruit));
}

I really hate this API because it always seems backward to me. Here is how i really want to use it

Assert.IsTrue(banana.CanBeAssignedTo(fruit));
Assert.IsFalse(fruit.CanBeAssignedTo(banana));

With the aid of an extension method we can easily achieve this

97 Things Every Programmer Should Know

Tue, 20 Jul 2010 00:00:00 +0000

97 Things Every Programmer Should Know was the last book that i wanted to read at the pool during summer holidays. As with all 97 things books you get a lot of valuable tips but i found this book not as exciting as the previous ones…

Debug It!: Find, Repair, and Prevent Bugs in Your Code

Tue, 20 Jul 2010 00:00:00 +0000

A while ago i noticed that Davy Brion recommended Debug It!: Find, Repair, and Prevent Bugs in Your Code so i decided to give it a read. Although i really liked the suggested process for investigating bugs where you have absolutely no clue of what is going on, i am not convinced that this is a must read book.

Implementing Lean Software Development: From Concept to Cash

Tue, 20 Jul 2010 00:00:00 +0000

Not going to waste time re-iterating what’s in the book because you can find that here: Implementing Lean Software Development: From Concept to Cash. Just make sure that you get your copy and read it from beginning to end. Afterwards you may want to hand it over to your manager 😉

Manage It!: Your Guide to Modern Pragmatic Project Management

Tue, 20 Jul 2010 00:00:00 +0000

A while ago i noticed that more and more of my work is related to coaching and managing other developers. In order to become better at that i ordered my copy of Manage It!: Your Guide to Modern Pragmatic Project Management. A book with plenty of useful (practical) tips. Definitely worth reading!

Removing Dead Tracks (Duplicates that don't exist) from iTunes using C#

Tue, 20 Jul 2010 00:00:00 +0000

Last week i noticed the following post from Scott Hanselman: Removing Dead Tracks (Duplicates that don’t exist) from iTunes using C#. As a good boy scout i noticed that these days iTunesLib.IITTrackCollection inherits from IEnumerable so i rewrote the code a little

class Program
{
	[STAThread]
	static void Main()
	{
		var itunes = new iTunesApp();
		itunes.DeleteTracksThatDoNotExist();
	}
}

public static class ITunesExtensions
{
	public static void DeleteTracksThatDoNotExist(this IiTunes itunes)
	{
		var tracksThatDoNotExist = FindTracksThatDoNotExist(itunes);
		foreach (var track in tracksThatDoNotExist) track.Delete();
	}

	public static IEnumerable<iitfileOrCDTrack> FindTracksThatDoNotExist(this IiTunes iTunes)
	{
		return iTunes.LibraryPlaylist.Tracks
			.OfType<iitfileOrCDTrack>()
			.Where(track => !File.Exists(track.Location));
	}
}

The Productive Programmer

Tue, 20 Jul 2010 00:00:00 +0000

The first part of the book covers some tools that may improve your productivity (but nothing that i did not use already). The second part covers development techniques (again, nothing new under the sun). Despite the author’s intentions i found reading The Productive Programmer a disappointment.

Sometimes you can write it better than Resharper

Sat, 03 Jul 2010 00:00:00 +0000

Here is a real-life example of when people are much better expressing intent than a tool: Consider the following code from a typical Silverlight Navigation application

foreach (UIElement child in LinksStackPanel.Children)
{
	var hb = child as HyperlinkButton;
	if (hb != null && hb.NavigateUri != null)
	{ .. }
}

Resharper proposed to write this as following

foreach (var hb in LinksStackPanel.Children
	.Select(child => child as HyperlinkButton)
	.Where(hb => hb != null && hb.NavigateUri != null))
	{ .. }

Here is what i wrote instead

foreach (var hb in LinksStackPanel.Children
	.OfType<hyperlinkButton>()
	.Where(hb => hb.NavigateUri != null))
	{ .. }

Convention over configuration with MSBuild

Sat, 26 Jun 2010 00:00:00 +0000

A while ago i blogged that i was using the TemplateFile task from the <a hrefhttp://msbuildtasks.tigris.org/">MSBuild Community Tasks Project to generate configuration files. Each project that required templating would have modified it’s csproj file as following

<!-- To modify your build process, add your task inside one of the targets below and uncomment it.
Other similar extension points exist, see Microsoft.Common.targets. -->
<import Project="$(MSBuildProjectDirectory)\config.msbuild" />
<target Name="BeforeBuild">
	<callTarget Targets="GenerateConfigurationFiles" />
</target>

And each of these config.msbuild files looked as following

Setting up a self-contained build

Sat, 26 Jun 2010 00:00:00 +0000

Here is something you may have experienced already: As a newcomer on an existing project, you check out the code from source-control and discover that the build is broken. When you ask around no-one else seems to have that problem but a helpful collegue is kind enough to tell you that you can find the installers for the missing dependencies at location X (Let’s not even mention the places where those installers are not available *sigh*).

97 Things Every Project Manager Should Know: Collective Wisdom from the Experts

Fri, 28 May 2010 00:00:00 +0000

Lately i felt the need to work on my management skills so apart from practicing each day i decided to search for some inspiration in 97 Things Every Project Manager Should Know: Collective Wisdom from the Experts. All i can say is that it’s yet another book in the series that is worth reading.

Microsoft SQL Server 2008 Internals

Fri, 28 May 2010 00:00:00 +0000

Around new year i found out that i would be working with SQL Server 2008 so i needed a crash course. Microsoft SQL Server 2008 Internals is really not intended to be that, but it does cover the basics and then dives (way too) deep in detail. Although i stopped reading halfway the dives i found the book very interesting!

Support both GET and HEAD requests on the same method with WCF REST

Fri, 28 May 2010 00:00:00 +0000

A while ago i had to modify an existing WCF REST service which was being consumed by BITS. Apparently the implementation has changed in Windows7 in such a way that the BITS client first makes a HEAD request to discover the file size.

The following attempts did not work

// A method can not have both WebGet and WebInvoke attributes
[OperationContract]
[WebGet]
[WebInvoke(Method="HEAD")]
public Stream Download(string token) { }

and

// A method can not have multiple WebInvoke attributes
[OperationContract]
[WebInvoke(Method="GET")]
[WebInvoke("HEAD")]
public Stream Download(string token) { }

The trick is to use * as Method and handle the method related logic in your code

WCF REST: generate correct Content-Length header for HEAD request

Fri, 28 May 2010 00:00:00 +0000

The point of a HEAD request is to return a Content-Length header, but with an empty body. The WCF transport stack has the annoying ‘feature’ that it ‘corrects’ the Content-Length header based on the stream that is returned. With the aid of Carlos Figueira’s MyLengthOnlyStream i was able to workaround that ‘feature’ :) (I know, i know, a good old HttpHandler is so much easier to implement!)

Windows Internals: Including Windows Server 2008 and Windows Vista, Fifth Edition

Fri, 28 May 2010 00:00:00 +0000

Given the fact that i have been developing software for MS-Windows the last couple of years i found it important to learn a bit more about the internals of the operating systems on which my applications run so i ordered a copy of Windows Internals: Including Windows Server 2008 and Windows Vista, Fifth Edition back in september and learned quite a bit from the chapters that i found interesting: security, authorization, networking and analyzing crashes. I skimmed through the chapters on memory management, scheduling and file systems because they reminded me too much of Tanenbaum’s excellent Modern Operating Systems.

Enumerating SpecialFolders

Sun, 02 May 2010 00:00:00 +0000

Environment.SpecialFolder is a value-type that i always seem to forget about. Let’s try to do something about that by posting about it here :)

foreach (var name in Enum.GetNames(typeof(Environment.SpecialFolder)))
{
	var specialFolder = (Environment.SpecialFolder)Enum.Parse(typeof(Environment.SpecialFolder), name);
	Console.WriteLine("{0,25} => {1}", name, Environment.GetFolderPath(specialFolder));
}

<td>
  C:\Users\timvw\AppData\Roaming\Microsoft\Windows\Start Menu\Programs
</td>

<td>
  C:\Users\timvw\Documents
</td>

<td>
  C:\Users\timvw\Documents
</td>

<td>
  C:\Users\timvw\Favorites
</td>

<td>
  C:\Users\timvw\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup
</td>

<td>
  C:\Users\timvw\AppData\Roaming\Microsoft\Windows\Recent
</td>

<td>
  C:\Users\timvw\AppData\Roaming\Microsoft\Windows\SendTo
</td>

<td>
  C:\Users\timvw\AppData\Roaming\Microsoft\Windows\Start Menu
</td>

<td>
  C:\Users\timvw\Music
</td>

<td>
  C:\Users\timvw\Desktop
</td>

<td>
</td>

<td>
  C:\Users\timvw\AppData\Roaming\Microsoft\Windows\Templates
</td>

<td>
  C:\Users\timvw\AppData\Roaming
</td>

<td>
  C:\Users\timvw\AppData\Local
</td>

<td>
  C:\Users\timvw\AppData\Local\Microsoft\Windows\Temporary Internet Files
</td>

<td>
  C:\Users\timvw\AppData\Roaming\Microsoft\Windows\Cookies
</td>

<td>
  C:\Users\timvw\AppData\Local\Microsoft\Windows\History
</td>

<td>
  C:\ProgramData
</td>

<td>
  C:\Windows\system32
</td>

<td>
  C:\Program Files
</td>

<td>
  C:\Users\timvw\Pictures
</td>

<td>
  C:\Program Files\Common Files
</td>

Desktop	C:\Users\timvw\Desktop
Programs
Personal
MyDocuments
Favorites
Startup
Recent
SendTo
StartMenu
MyMusic
DesktopDirectory
MyComputer
Templates
ApplicationData
LocalApplicationData
InternetCache
Cookies
History
CommonApplicationData
System
ProgramFiles
MyPictures
CommonProgramFiles

Get root directory for IsolatedStorageFiles

Sat, 01 May 2010 00:00:00 +0000

Sometimes you want to know the absolute path of a file that is persisted with IsolatedStorageFile. Apparently there is an internal property RootDirectory which contains this information

public static class IsolatedStorageFileExtensions
{
	public static string GetRootDirectory(this IsolatedStorageFile isf)
	{
		var property = isf.GetType().GetProperty("RootDirectory", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.GetProperty);
		return (string)property.GetValue(isf, null);
	}
}

Here is a real world example of using SharpBITS.NET to download a file to IsolatedStorage:

class Program
{
	static void Main()
	{
		var mgr = new BitsManager();
		mgr.OnJobError += mgr_OnJobError;
		mgr.OnJobTransferred += mgr_OnJobTransferred;

		var job = mgr.CreateJob("job@" + DateTime.Now, JobType.Download);
		var src = @"http://localhost/";
		var dst = Path.Combine(GetIsfRoot(), "test.html");
		job.AddFile(src,dst);
		job.Resume();

		Console.WriteLine("running...");
		Console.ReadKey();
	}

	static void mgr_OnJobTransferred(object sender, NotificationEventArgs e)
	{
		e.Job.Complete();
		Console.WriteLine("completed: " + e.Job.DisplayName);
	}

	static void mgr_OnJobError(object sender, ErrorNotificationEventArgs e)
	{
		Console.WriteLine("error: " + e.Error.Description);
	}

	static string GetIsfRoot()
	{
		using (var f = IsolatedStorageFile.GetUserStoreForAssembly())
		{
			return f.GetRootDirectory();
		}
	}
}

97 Things Every Software Architect Should Know: Collective Wisdom from the Experts

Mon, 19 Apr 2010 00:00:00 +0000

I learned a couple of valuable lessons from 97 Things Every Software Architect Should Know: Collective Wisdom from the Experts so i would certainly recommend this very readabile book!

Exploring System.Interactive

Thu, 18 Feb 2010 00:00:00 +0000

A couple of weeks ago i was working on an application that would transfer data through a couple of components as a List. In essence, all we were doing over and over again was the following:

interface IMapper
{
	TEntity FromObjectList(List objectList);
	List ToObjectList(TEntity entity);
}

My initial implementation (using EnumerableEx operators from Reactive Extensions) looked like this

public TEntity FromObjectList(List objectList)
{
	var entity = new TEntity();
	
	properties
		.Zip(objectList, (property, value) => AssignValueToProperty(entity, property, value))
		.Run();

	return entity;
}

int AssignValueToProperty(object entity, PropertyInfo property, object value)
{
	property.SetValue(entity, value, null);
	return 0;
}

public List ToObjectList(TEntity entity)
{
	return properties
	.Select(property => property.GetValue(entity, null))
	.ToList();
}

And the consumer code looks like this:

Learned something from Resharper: Enumerable.OfType

Wed, 17 Feb 2010 00:00:00 +0000

A couple of weeks ago i discovered Enumerable.OfType when i let Resharper rewrite my code as a Linq statement. Here is the original code:

var selectedPersons = new List<personSelectItem>();
foreach(var selectedItem in selectedItems)
{
	var selectedPerson = selectedItem as PersonSelectItem;
	if (selectedPerson == null) continue;
	selectedPersons.Add(selectedPerson);
}

And here is how it looks after the rewrite:

var selectedPersons = selectedItems.OfType<personSelectItem>().ToList();

Yup, the Resharper license was definitely worth it’s money.

Calculate EndpointAddress for Silverlight client

Mon, 15 Feb 2010 00:00:00 +0000

Because Silverlight checks the origin it considers http://localhost and http://127.0.0.1 as different locations. In case you want your visitors to be able to use both addresses you can recalculate the address as following:

EndpointAddress GetEndpointAddress(EndpointAddress endpointAddress)
{
	var scheme = Application.Current.Host.Source.GetComponents(UriComponents.Scheme, UriFormat.Unescaped);
	var serverAndPort = Application.Current.Host.Source.GetComponents(UriComponents.HostAndPort, UriFormat.Unescaped);
	var pathAndQuery = endpointAddress.Uri.GetComponents(UriComponents.PathAndQuery, UriFormat.Unescaped);
	return new EndpointAddress(scheme + "://" + serverAndPort + pathAndQuery);
}

And you can use this method as following:

var client = new DirectoryServiceClient();
client.Endpoint.Address = GetEndpointAddress(client.Endpoint.Address);
client.GetMessageCompleted += ClientGetMessageCompleted;
client.GetMessageAsync();

Clever TemplateFile hack

Fri, 12 Feb 2010 00:00:00 +0000

In my current project i use TemplateFileTask (MSBuild Community Tasks Project) to generate configuration files. I ran into the problem that i don’t want to expose a MEX endpoint in production. This is my initial template file

<service behaviorconfiguration="DemoBehavior" name="DemoService.FileService">
	<endpoint address="" binding="ws2007HttpBinding" contract="DemoService.IFileService" />
	${MexEndpoint}
</service>

And here is my initial msbuild task

<Project ToolsVersion="3.5" dDfaultTargets="GenerateConfigFiles" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
	<Import Project="$(MSBuildExtensionsPath)\MSBuildCommunityTasks\MSBuild.Community.Tasks.Targets"/>
	<Target Name="GenerateConfigFiles">
		<PropertyGroup>
			<MexEndpoint>
				<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
			</MexEndpoint>
		</PropertyGroup>

		<PropertyGroup Condition=" '$(Env)'=='Production' ">
			<MexEndpoint></MexEndpoint>
		</PropertyGroup>

		<ItemGroup>
			<Tokens Include="MexEndpoint">
				<ReplacementValue>$(MexEndpoint)</ReplacementValue>
			</Tokens>
		</ItemGroup>

		<TemplateFile Template="Web.template.config" OutputFileName="Web.config" Tokens="@(Tokens)" />
	</Target>
</Project>

This results in the following configuration file: (WCF does not like the xml namespace declaration):

Another missing method for IEnumerable

Wed, 10 Feb 2010 00:00:00 +0000

Currently there are two overloads for OrderBy on Enumerable

OrderBy(this IEnumerable source, Func<TSource, TKey> keySelector)
OrderBy(this IEnumerable source, Func<TSource, TKey> keySelector, IComparer comparer)

Because i don’t want to implement an IComparer each time i have implemented the following class

class DelegateComparer<T> : IComparer<T>
{
	public Func<t, T, int> CompareFunction { get; set; }

	public DelegateComparer(Func<t, T, int> compareFunction)
	{
		CompareFunction = compareFunction;
	}

	public int Compare(T x, T y)
	{
		return CompareFunction(x, y);
	}
}

And now i can define a nice extension method:

Verify that a X509Certificate can be used for key exchange

Tue, 02 Feb 2010 00:00:00 +0000

Here is another method that earned it’s place in my ever growing toolbox:

public static bool CanDoKeyExchange(this X509Certificate2 certificate)
{
	if (!certificate.HasPrivateKey) return false;

	var privateKey = certificate.PrivateKey as RSACryptoServiceProvider;
	if (privateKey == null) return false;

	var canDoKeyExchange = privateKey.CspKeyContainerInfo.KeyNumber == KeyNumber.Exchange;
	return canDoKeyExchange;
}

Presenting ValueType

Thu, 28 Jan 2010 00:00:00 +0000

Here is a base class for some code that i have written once too many in my life: (In case you’re an early adaptor (.Net 4.0) you may want to use System.Tuple as base class)

public class ValueType<T> : IComparable, IComparable<valueType<T>>, IEquatable<valueType<T>> where T : IComparable<T>
{
	protected T Value { get; private set; }
	
	public ValueType(T value)
	{
		Value = value;
	}

	public override int GetHashCode()
	{
		return Value.GetHashCode();
	}

	public override string ToString()
	{
		return Value.ToString();
	}

	public override bool Equals(object obj)
	{
		return Equals(obj as ValueType<T>);
	}

	public bool Equals(ValueType<T> other)
	{
		return Compare(this, other) == 0;
	}

	public int CompareTo(object obj)
	{
		return CompareTo(this, obj as ValueType<T>);
	}

	public int CompareTo(ValueType<T> other)
	{
		return Compare(this, other);
	}

	static int Compare(ValueType<T> instance1, ValueType<T> instance2)
	{
		if (ReferenceEquals(instance1, instance2)) return 0;
		if (ReferenceEquals(instance1, null)) return -1;
		if (ReferenceEquals(instance2, null)) return 1;

		if (ReferenceEquals(instance1.Value, instance2.Value)) return 0;
		if (ReferenceEquals(instance1.Value, null)) return -1;
		if (ReferenceEquals(instance2.Value, null)) return 1;

		return instance1.Value.CompareTo(instance2.Value);
	}

	public static bool operator ==(ValueType<T> instance1, ValueType<T> instance2)
	{
		return Compare(instance1, instance2) == 0;
	}

	public static bool operator !=(ValueType<T> instance1, ValueType<T> instance2)
	{
		return !(instance1 == instance2);
	}

	public static bool operator <(ValueType<T> instance1, ValueType<T> instance2)
	{
		return Compare(instance1, instance2) < 0; 
	} 
		public static bool operator >(ValueType<T> instance1, ValueType<T> instance2)
	{
		return Compare(instance1, instance2) > 0;
	}
}

Do we need an EventAggregator when we have an IOC container?

Wed, 27 Jan 2010 00:00:00 +0000

An Event Aggregator is an example of a Publish/Subscribe channel. A while ago i started wondering if we still need an Event Aggregator in our compisite applications if we have an IOC container that takes cares of dependency wiring. An IOC container can easily inject the Event/MessageHandler(s) in the Event/MessagePublisher(s)… I’m still not sure about the answer (Yes/No).

About dependencies

Tue, 26 Jan 2010 00:00:00 +0000

This weekend i noticed a couple of posts by Uncle Bob trying to get some discussions going. In Mocking Mocking and Testing Outcomes at some point he generates a fake of some class

“Oh, ick!” you say. Yes, I agree it’s a lot of code. On the other hand, it took me just a single keystroke on my IDE to generate all those dummy methods. (In IntelliJ it was simply command-I to implement all unimplemented methods.) So it wasn’t particularly hard. And, of course, I can put this code somewhere where nobody had to look at it unless they want to. It has the advantage that anybody who knows Java can understand it, and can look right at the methods to see what they are returning. No “special” knowledge of the mocking framework is necessary.

About forced design

Sat, 23 Jan 2010 00:00:00 +0000

if you need typemock your design is wrong.

Although i understand what people are trying to say with that quote, it’s wrong on many levels. I pretty much agree with everything that Roy wrote in Test driven design – Willed vs. Forced Designs. As some commenters pointed out it is hard to convince management that they need an isolation framework, let alone that they have to pay for one.

A couple of thoughts:

Programming the Bus Pirate with C#

Sat, 16 Jan 2010 00:00:00 +0000

A while ago i received my Bus Pirate from Seeed Studio Depot. In essence it is a universal serial bus interface and i would love to program it using c#. I know that i can use the DataReceived event and then fiddle with bits (read here if you’re into that kind of self-punishment) but spawning a separate thread to do the blocking work is ten times less work to get it up and running

About raising events

Sat, 09 Jan 2010 00:00:00 +0000

Very often i see people write the following to ‘safely’ raise a method

public event EventHandler Stopped;

void RaiseStoppedEvent()
{
	if (Stopped != null) Stopped(this, EventArgs.Empty);
}

Some developers think that they should program defensively and avoid the potential concurrency problem

public event EventHandler Stopped;

void RaiseStoppedEvent()
{
	var handler = Stopped;
	if (handler!= null) handler(this, EventArgs.Empty);
}

And then there is Tim’s way to raise an event: (If i’m not mistaken it was Ayende who once blogged about this)

Add "Run as administrator" to .sln files

Sat, 09 Jan 2010 00:00:00 +0000

Another trick i learned from the “How-To Geek” is how to add a “Run as administrator” option in the windows shell for .sln files which makes life considerably easier 😉

Creating graphs with the Silverlight Toolkit

Fri, 08 Jan 2010 00:00:00 +0000

As i wrote already: In a chart the elements on the X-axis are usually numbers or dates, and the elements on the Y-axis are usually doubles. We can define such a combination as following

public class Point<T>
{
	public T X { get; set; }
	public double Y { get; set; }
}

Here is a little helper function for creating line series that are used by the Silverlight Toolkit:

public LineSeries Create<T>(string title, Series<T> series, Func<t, double> f) where T : IComparable<T>
{
	var points = series.Select(x => new Point<T> { X = x, Y = f(x) });

	var lineSeries = new LineSeries
	{
		Title = title,
		ItemsSource = points,
		IndependentValuePath = "X",
		DependentValuePath = "Y"
	};

	return lineSeries;
}

Given all this infrastructure we can easily draw the graph of a function:

Creating series of elements

Fri, 08 Jan 2010 00:00:00 +0000

Lately i have done quite a bit of charting. Very often the X-axis is populated with a series of numbers or dates. This can be as simple as: (My very little DSL in Jeremy D. Miller Style)

[Test] public void ShouldBeAbleToGetSeriesOfNumbers()
{
	// Arrange
	var series = 3.To(5);

	// Act
	var elements = series.Elements;

	// Assert
	var expected = new[] { 3, 4, 5 };
	CollectionAssert.AreEqual(expected, elements);
}

[Test] public void ShouldBeAbleToGetSeriesOfDays()
{
	// Arrange
	var now = DateTime.Now.Date;
	var twoDaysLater = now.AddDays(2);
	var series = now.To(twoDaysLater);

	// Act
	var elements = series.Elements;

	// Assert
	var expectedDays = new[] { now, now.AddDays(1), now.AddDays(2) };
	CollectionAssert.AreEqual(expectedDays, elements);
}

And here is the code that makes these tests pass

Refactoring to Patterns

Sun, 27 Dec 2009 00:00:00 +0000

Earlier this month i ordered my copy of Refactoring to Patterns. This books has two parts: the first part describes patterns and code smells (anti-patterns) and the second part is a catalog of refactorings. The first part is not bad, but i appreciated the second part much more. I did not read the book from front to cover and skipped the ‘mechanics’ sections (abstract steps to take in order to accomplish a particular refactoring). I focussed on the ’example’ sections instead which demonstrate the application of the previously mentionned mechanics.

Ninject: connect an IProxyFactory component to the kernel

Wed, 16 Dec 2009 00:00:00 +0000

Because it’s the second time that i run into this i will post the solution here so that i (and all the other people that run into the same issue) can easily solve it next time. Anyway, i was playing with Ninject and ran into the following exception:

Error activating XXX: the implementation type YYY requests static interceptors, or dynamic interceptors have been defined.

In order to provide interception, you must connect an IProxyFactory component to the kernel.

The Nomadic Developer: Surviving and Thriving in the World of Technology Consulting

Mon, 07 Dec 2009 00:00:00 +0000

This is probably one of the shortest book reviews ever, but there is not much to say about The Nomadic Developer: Surviving and Thriving in the World of Technology Consulting. Just read it if you are (or considering to become) an IT-consultant because it really covers both good and bad aspects in depth.

Bing vs Google in 5 seconds

Sat, 05 Dec 2009 00:00:00 +0000

A while ago i sat in a meeting and some ms-fanboy used Bing to find out how much 60 inches were in meters. The first page had pages with conversion factors but none of them contained the actual answer. I suggested that he’d use Google instead and while he was keying in the question the answer already appeared.

Today i wanted to make a screencast of this difference in experience but it seems that bing has the ‘conversion’ feature now too. Wondering about what would make me switch search engines…

In case you really have to Append one array to another

Fri, 04 Dec 2009 00:00:00 +0000

Here is another problem i’ve seen people solve once too many: Append one array to another. STOP. Revisit the problem. Can’t you simply use List and move on to solving actual business problems? In case you really can’t get rid of the arrays read the following

Given()
{
	source = new[] { SourceElement };
	destination = new[] { DestinationElement };
}

and

When()
{
	source.AppendTo(ref destination);
}

and

ThenTheDestinationShouldStillHaveTheDestinationElement()
{
	Assert.AreEqual(DestinationElement, destination[0]);
}

and

Easy pattern for Control state

Sat, 21 Nov 2009 00:00:00 +0000

If you have decided that your WebControl requires to maintain it’s state you will want to figure out how to implement Control state. Most examples on the web will then create an array of objects and then hardcode the indices to find stuff back… Simply define a serializable inner class and use that instead of the ‘magic array object’. Eg

class SilverlightHost : WebControl
{
	[Serializable]
	class State
	{
		public object BaseState { get; set; }
		public string SilverlightUrl { get; set; }
		public string SilverlightErrorHandlerUrl { get; set; }
		public Dictionary<string, string> Parameters { get; set; }
	}

	protected override void OnInit(EventArgs e)
	{
		base.OnInit(e);
		Page.RegisterRequiresControlState(this);
	}

	protected override object SaveControlState()
	{
		var state = new State
		{
			BaseState = base.SaveControlState(),
			SilverlightUrl = SilverlightUrl,
			SilverlightErrorHandlerUrl = SilverlightErrorHandlerUrl,
			Parameters = parameters
		};
		return state;
	}

	protected override void LoadControlState(object savedState)
	{
		var state = (State)savedState;
		SilverlightUrl = state.SilverlightUrl;
		SilverlightErrorHandlerUrl = state.SilverlightErrorHandlerUrl;
		parameters = state.Parameters;
		base.LoadControlState(state.BaseState);
	}
}

Silverlight and unit testing..

Thu, 19 Nov 2009 00:00:00 +0000

A while ago i was looking for a unittesting framework that can be used with Silverlight. Because i don’t want to launch a webbrowser on my buildserver i ruled the Unit Test Framework for Microsoft Silverlight out. A couple of websearches later i decided to try a Silverlight port of good ol’ NUnit, nunitsilverlight, and was pretty pleased with results.

A couple of things to keep in mind though:

Make sure your test runner loads the correct System assembly (Possible solution: set Copy Local to true in your test project)
In case your test runner has to run tests in both ‘regular’ and ‘silverlight’ assemblies, make sure that your runner uses separate AppDomains (For NUnit use the /Domain=Multiple option)

Couple of methods missing on ObservableCollection

Fri, 06 Nov 2009 00:00:00 +0000

Here are a couple of methods that are missing on ObservableCollection

public static class ObservableCollectionExtensions
{
	public static void AddRange<T>(this ObservableCollection<T> observableCollection, IEnumerable<T> elements)
	{
		foreach (var element in elements) observableCollection.Add(element);
	}

	public static ObservableCollection<T> Create<T>(IEnumerable<T> elements)
	{
		var observableCollection = new ObservableCollection<T>();
		observableCollection.AddRange(elements);
		return observableCollection;
	}
}

Presenting FilterList

Fri, 06 Nov 2009 00:00:00 +0000

Earlier today i decided to add ‘Filtering’ to my SortableBindingList. This resulted in writing a FilterList class. This class can be easily used as following

void textBoxFilter_KeyUp(object sender, KeyEventArgs e)
{
	var filterChars = this.textBoxFilter.Text.ToLower();
	this.Filter(filterChars);
}

void Filter(string filterChars)
{
	var persons = (FilterList<person>)this.dataGridView1.DataSource;
	persons.Filter(p => p.Firstname.ToLower().Contains(filterChars));
}

I even created a screencast to demonstrate it:

[mediaplayer src=‘http://www.timvw.be/screencasts/filterlist.wmv’ width=512 height=344]

Another method i wrote once too many

Sun, 01 Nov 2009 00:00:00 +0000

Virtually every Silverlight application will fetch resources at one point or another. In case you’re using the WebClient you have probably written the following in your xxxCompletedEventHandler

if (e.Error != null && !e.Cancelled)
{
	// do something with the result
}

Anyway, i don’t like repetition so i captured the conditions in a method:

public static class ExtensionMethods
{
	public static bool HasResult(this AsyncCompletedEventArgs e)
	{
		if (e.Error != null) return false;
		if (e.Cancelled) return false;
		return true;
	}
}

And now we can write our code as:

if (e.HasResult())
{
	// do something with the result
}

Apart from saving a couple of keystrokes this also allows us to easily add another condition to determine the success of the operation.

Party for one

Thu, 29 Oct 2009 00:00:00 +0000

Inspired by Jimmy Bogard’s More missing LINQ operators i found another one

public static IEnumerable<T> MakeEnumerable<T>(this T element)
{
	yield return element;
}

Presenting PathBuilder

Thu, 29 Oct 2009 00:00:00 +0000

Currently it is annoying to build a path with Path.Combine

var home1 = Path.Combine(Path.Combine(Path.Combine("C", "Users"), "timvw"), "My Documents");

And here is how it can be:

var home2 = PathBuilder.Combine("C", "Users", "timvw", "My Documents");

The implementation is pretty simple:

public static class PathBuilder
{
	public static string Combine(params string[] parts)
	{
		return parts.Aggregate((l, r) => Path.Combine(l, r));
	}
}

Separation of concerns: Behavior = Trigger + TriggerAction

Mon, 19 Oct 2009 00:00:00 +0000

If you look at my KeyBehavior you notice that it is doing two things: register for events so that the behavior can be triggered and handle the actual command invocation. In order to enhance reuse we can refactor this KeyBehavior in a KeyTrigger and an InvokeCommandAction. Well, we’re not going to do that, because they exist already in the silverlight sdk.

A shortcoming of the InvokeCommandAction is that it can only invoke commands on the FrameworkElement itself, thus we write a custom implementation that finds commands on the DataContext instead

True KeyBehavior with System.Windows.Interactivity.Behavior

Mon, 19 Oct 2009 00:00:00 +0000

Yesterday i demonstrated how attached properties can be used to invoke commands on specific key presses (and releases). With the aid of System.Windows.Interactivity.Behavior we can implement a true behavior and we get an extension point to do the required cleanup.

<grid>
	<interactivity:Interaction.Behaviors>
		<inf:KeyBehavior>
			<inf:KeyBehavior.DownKeyCommands>
				<inf:KeyCommandName Key="Right" CommandName="PlayerRight" />
				<inf:KeyCommandName Key="Left" CommandName="PlayerLeft" />
				<inf:KeyCommandName Key="Up" CommandName="PlayerUp" />
				<inf:KeyCommandName Key="Down" CommandName="PlayerDown" />
			</inf:KeyBehavior.DownKeyCommands>
		</inf:KeyBehavior>
	</interactivity:Interaction.Behaviors>
...
</grid>

The behavior implementation is the same as yesterday, only this time we thankfully override the OnAttached and OnDetaching methods

Silverlight: leveraging attached properties to handle key events

Sat, 17 Oct 2009 00:00:00 +0000

I strongly believe that input handling is a responsability that belongs to the View. At first i simply added the following in the code-behind of my GameView

protected override void OnKeyDown(KeyEventArgs e)
{
	base.OnKeyDown(e);

	if (e.Key == Key.Left) Model.MovePlayerLeft();
	...
}

But i wanted to play with the cool kids so i exposed ICommand properties on my ViewModel instead and rewrote the code like this

protected override void OnKeyDown(KeyEventArgs e)
{
	base.OnKeyDown(e);

	if (e.Key == Key.Left) Model.PlayerLeft.Execute(null);
	...

Offcourse, designers should not have to write code at all, thus i searched for a different solution. Because there isn’t a behavior that allows me to differentiate the command based on the actual key being pressed i wrote my own KeyEvents class which allows the designer to map a key to a command. Here is an example

Exploring graphical programming with Blend, Visual State Manager and Behaviors

Fri, 16 Oct 2009 00:00:00 +0000

A while ago i presented the ControlStateMachine and in Silverlight this concept is implemented as the Visual State Manager.

In my sokoban implementation i have a cellview which exists out of 6 canvasses but only two of them (one for the cell type and one for the piece type) are visible at any given point in time. I have implemented this with 6 properties CanvasXVisible (with X being Player, Box, Wall, Goal, Floor and Cell) in my ViewModel but a State Machine / Manager may help clarify how the visibility of the canvasses are related. Here are the 2 visual state groups and their states that i would need for the CellView

About databinding and composite views

Tue, 13 Oct 2009 00:00:00 +0000

A couple of days ago i had a databound ItemsControl (collection of Model.Cell) which instantiated sub views (with their own viewmodel).

<grid>
	<grid.Resources>
		<dataTemplate x:Key="CellTemplate">
			<views:CellView />
		</dataTemplate>
	</grid.Resources>
	<itemsControl ItemTemplate="{StaticResource CellTemplate}" ItemsSource="{Binding Cells}" />
</grid>

Because each CellViewModel needs to know which cell they manage i used the following dirty hack

public CellView()
{
	Loaded += CellView_Loaded;
}

void CellView_Loaded(object sender, RoutedEventArgs e)
{
	DataContext = new CellViewModel(DataContext);
}

Later on that day i realised there was a much cleaner solution: Let the BoardViewModel expose a collection of ViewModels.CellViewModel instead of Model.Cell. What a relief that i don’t have to use the Loaded event hack.

Exploring M-V-VM

Tue, 13 Oct 2009 00:00:00 +0000

A couple of years ago a collegue recommended Data Binding with Windows Forms 2.0: Programming Smart Client Data Applications with .NET and i noticed that my code started to gravitate towards an Model-View-ViewModel architecture. Due to shortcomings and painful experiences i gave up on databinding and began to use Passieve View instead.

Passive View doesn’t work (well) with smart views so i decided to give M-V-VM another because i really wanted to leverage WPF’s rich support for databinding.

ViewModel to translate domain messages to view events

Tue, 13 Oct 2009 00:00:00 +0000

Here is an example of a ViewModel that translates domain messages to view events:

class GameViewModel : INotifyPropertyChanged, IListener<boardChanged>
{
	public event PropertyChangedEventHandler PropertyChanged = delegate { };

	public GameViewModel()
	{
		var messageBus = ServiceLocator.MessageBus;
		messageBus.Subscribe<boardChanged>(this);
	}

	void IListener<boardChanged>.Handle(BoardChanged message)
	{
		PropertyChanged("Board");
	}
}

Sokoban: Creating graphics with Expression Design

Mon, 12 Oct 2009 00:00:00 +0000

Earlier this morning i decided to improve the graphics the little. I launched Expression Design, created a new image, and drew each possible cell and piece in a seperate layer. With this technique i can easily preview how a “Box” on “Goal” looks like.

For each layer i simply copied the XAML from Expression Design into my Cell.xaml file. Apparently all the layers are interpreted as a Canvas and the layer name determines their x:Name which makes it pretty easy to make the correct canvasses visible. With a simple ScaleTransform i can ensure that the canvasses are sized correctly.

Presenting Sokoban with Silverlight

Sat, 10 Oct 2009 00:00:00 +0000

Despite the blablah postings, i have been able to code a little, so here is the boomboom: Sokoban.

Silverlight wishlist

Sat, 10 Oct 2009 00:00:00 +0000

Here are the features that i would love to see in Silverlight:

Allow users to copy text from the UI (Or was the UX argument an excuse for playing with new toys?)
MSTEST (I know that [Here are the features that i would love to see in Silverlight:
Allow users to copy text from the UI (Or was the UX argument an excuse for playing with new toys?)
MSTEST (I know that](http://code.msdn.microsoft.com/silverlightut/) exists.)

Configuring Apache to serve Office 2007 documents with the correct MIME type

Fri, 09 Oct 2009 00:00:00 +0000

Untill now i haven’t published any Office 2007 documents but i noticed that my webhost hasn’t configured apache to serve such documents with the correct MIME types. This resulted in my web browser downloading .docx files as zip archives. Here’s how a couple of additions to .htaccess tackle the problem:

AddType application/vnd.openxmlformats-officedocument.spreadsheetml.sheet xlsx
AddType application/vnd.openxmlformats-officedocument.spreadsheetml.template xltx
AddType application/vnd.openxmlformats-officedocument.presentationml.template potx
AddType application/vnd.openxmlformats-officedocument.presentationml.slideshow ppsx
AddType application/vnd.openxmlformats-officedocument.presentationml.presentation sldx
AddType application/vnd.openxmlformats-officedocument.presentationml.slide sldx
AddType application/vnd.openxmlformats-officedocument.wordprocessingml.document docx
AddType application/vnd.openxmlformats-officedocument.wordprocessingml.template dotx
AddType application/vnd.ms-excel.addin.macroEnabled.12 xlam
AddType application/vnd.ms-excel.sheet.binary.macroEnabled.12 xslb

Fluent Builders: More than creating context specifications

Thu, 08 Oct 2009 00:00:00 +0000

Last couple of months i have been using the concept of (Fluent) Builder classes in order to create context specifications and i blogged about the steps i take to design their API. Lately i have realised that this concept has more uses than context specifcation only. Here is an example:

In sokoban a game board can be stored in plain text using the following ‘protocol’:

Level element	Character
Wall	#
Player	@
Player on Goal	+
Box	$
Box on Goal	*
Goal	.
Floor	(space)

Notice how a Fluent Builder allows us to implement this protocol with some elegant code:

Fluent Builders: The case against implicit conversion

Thu, 08 Oct 2009 00:00:00 +0000

Most people add an implicit conversion to their builder API which gives them the advantage that they don’t have to call Build explicitely. I have decided that i do not want to have this implicit conversion for a couple of reasons:

C# does not allow to define implicit conversions to or from an interface
Implicit conversions are not very discoverable
Implicit conversions can break the API

Here is an example to clarify that last reason: Consider an OrderBuilder which requires the user to provide a product and then a quantity:

Fluent Builders: The case against implicit conversion (2)

Thu, 08 Oct 2009 00:00:00 +0000

Here is another example that demonstrates how implicit conversion in a Fluent Builder can lead to surprises (Jan Van Ryswyck noticed this too). Originally the code in my previous example was the following:

var order = new OrderBuilder();

Wich would make the c# compiler conclude that order is an OrderBuilder instead of an Order.

MSTEST tip: Add "Full Class Name" column to results view

Thu, 08 Oct 2009 00:00:00 +0000

I firmly believe that adding the ‘Full Class Name’ column to MSTEST’s result view makes it a lot easier to clarify the requirements:

About Expression Blend

Mon, 05 Oct 2009 00:00:00 +0000

At first i developed most WPF interfaces by writing XAML in the code view of Visual Studio. Those days are gone 😉 These days i find it a lot easier to use Expression Blend (eg: paths, animations and timelines) but i reallly don’t like it that Blend adds design-time information to the XAML that is intended to be used in production code. A tool should not add clutter to your code!

Professional WPF Programming: NET Development with the Windows Presentation Foundation

Mon, 05 Oct 2009 00:00:00 +0000

I am very disappointed with Professional WPF Programming: NET Development with the Windows Presentation Foundation. Apart from the two chapters that cover Expression Blend i found nothing worth reading in this book. This is probably the last Wrox book that i buy.

Programming WPF, Second Edition

Mon, 05 Oct 2009 00:00:00 +0000

I felt it was time to get up to speed with WPF so i decided to buy Programming WPF, Second edition. This book answered a lot of my newbie questions (where is the application entry point etc) right from the start. I liked it so much that i decided to read a second time 😉 Most definitely recommended.

Brad Abrams and extension methods to the rescue..

Tue, 29 Sep 2009 00:00:00 +0000

Currently i am implementing Sokoban and i was pondering which methods i should add to my Cell class:

bool HoldsWall
bool HoldsBox
bool HoldsPlayer

bool HoldsPieceOfType(Type type)

Which option should i choose? With the aid of extension methods (in the same namespace) i can have them both:

namespace Sokoban.Domain
{
	public static class ExtensionMethods
	{
		public static bool HoldsBox(this Cell cell)
		{
			return cell.HoldsPieceOfType(typeof(Box));
		}

		public static bool HoldsPlayer(this Cell cell)
		{
			return cell.HoldsPieceOfType(typeof(Player));
		}

		public static bool HoldsWall(this Cell cell)
		{
			return cell.HoldsPieceOfType(typeof(Wall));
		}
	}
}

In case you don’t like this solution, blame Brad Abrams who inspired me to implement it this way with his session at Visug yesterday.

Improve readability with LINQ

Tue, 29 Sep 2009 00:00:00 +0000

At first i was not very fond of LINQ but it seems that i am finally convinced that LINQ may improve readability:

bool IsCompleted()
{
	var boxesNotOnGoal = from cell in Cells
	where cell.HoldsBox() && !cell.IsGoal()
	select cell.Piece;

	return boxesNotOnGoal.Any();
}

Tim.TransitionTo("MCPD: Enterprise Application Developer 3.5")

Fri, 18 Sep 2009 00:00:00 +0000

I figured that it might help convince people that i stay up to date with current technology so i decided to take (and pass) the following exams: 70-568 and 70-569. This means that i have now earned the following credentials:

MCPD: Enterprise Application Development 3.5
MCTS: .NET Framework 3.5, Windows Forms Applications
MCTS: .NET Framework 3.5, ASP.NET Applications
MCTS: .NET Framework 3.5, Windows Communication Foundation Applications
MCTS: .NET Framework 3.5, ADO.NET Applications

About under construction pages

Fri, 11 Sep 2009 00:00:00 +0000

Why do people visit a website? To find information. Thus, when you publish a page to announce that the information is not there (yet) you are wasting your visitors time. Instead of creating the actual content you wasted time while your were creating an under construction page. A loss-loss situation instead of a win-win one.

Admitted, in some cases it can be helpful to give your visitors an idea of what they can expect (eg: links to articles that are not written yet appear in red in the Presentation Patterns wiki), but in general: Under construction pages stink. And here is someone who shares that feeling: This icon says more about me than it does about my web page.

Instruct T4 to use C# v3.5

Fri, 11 Sep 2009 00:00:00 +0000

Consider this simple T4 template:

<# for (var i = 0; i < 10; ++i) { WriteLine("hello"); } #>

Trying to build the project results in a compilation error because ‘var’ is an unknown type. A bit of research learned me that i should instruct the processor to use a specific c# version like this:

<#@ template language="C#v3.5" inherits="Microsoft.VisualStudio.TextTemplating.VSHost.ModelingTextTransformation" #>
<# for (var i = 0; i < 10; ++i) { WriteLine("hello"); } #>

Problem solved 🙂

Advertising on this blog

Sat, 29 Aug 2009 00:00:00 +0000

If you are an Adblock Plus user like me it is very likely that you have not noticed that i added Google Ads to this blog a month or two ago. Given that the total earnings are less than 5$ i have decided to remove them.

Extension methods to improve readability

Fri, 28 Aug 2009 00:00:00 +0000

A common reason to take advantage of extension methods is to enhance readability (think fluent interfaces). My team uses the specification pattern regularly and in case a requirement says something like “if the player has reached level 10 a message should be displayed” they would implement it as

if (new HasReachedLevel(10).IsSatisfiedBy(player))
{
	view.DisplayMessage("Congratulations! You have reached level 10.");
}

Pretty good but did you notice that they changed the order of player and level in their (code) story? With the aid of an extension method we can express this requirement as

About the design of a fluent interface

Mon, 17 Aug 2009 00:00:00 +0000

Now that i have presented a simple ControlStateMachine i can raise the bar a little. A statemachine that handles commands. Here is how a developer should be able to initialize this machine:

sut.WhenIn(States.Loading)
.On(Commands.Next)
.Do(() => Console.WriteLine("got next command while loading..."))
.Do(() => Console.WriteLine("doing it again..."))
.On(Commands.Previous)
.Do(() => Console.WriteLine("got previous command while loading..."));

sut.WhenIn(States.Ready)
.On(Commands.Previous)
.Do(() => Console.WriteLine("got previous command while ready..."));

So how should we define our methods to accomplish this initialization style? Let’s begin with identifying the methods we need.

About the implementation of a fluent interface

Mon, 17 Aug 2009 00:00:00 +0000

Now that i have defined my API for initialization it is time to implement it. Inspired by the Moq.Language and Moq.Language.Flow namespaces in Moq i have decided to define my interfaces in a separate namespace: Infrastructure.StateMachineLanguage.

Ever since i have read Clean code i feel the need to write classes that do one thing (and one thing only) so i came up with the following classes

something to store commands per state, CommandsForState
something to store actions per command, ActionsForCommand

For the implementation of the IChooseCommandAndAction interface i have decided to create a class that falls back on my classes that handle IChooseCommand and IChooseAction already

Presenting ControlStateMachine

Mon, 17 Aug 2009 00:00:00 +0000

Here is a situation we are all familiar with: A form that only displays a certain set of controls depending on the mode or state of the application. Let me start with an example: At design time there are three buttons

The user can look at the data and decide to edit it:

Presenting ControlChanges

Sat, 15 Aug 2009 00:00:00 +0000

Because i noticed that i kept writing the same operations on control over and over again i decided to capture them in a couple of functions. I presume most of you have done this already. Here is the list of operations:

In case it is not clear what these methods should do i have defined the following specifications for them:

About reading books

Thu, 13 Aug 2009 00:00:00 +0000

A while ago Gabriel wrote the following:

PS3: you can read all the books that you want, in the end to truly master .NET you need experience and more experience! Normally it would take you about 10 years of relevant experience to get to that level of expertise

I agree that expertise only comes from experience but i do believe that good books can guide you to the pit of success and help you recognize solutions that are doomed to fail.

Clean Code: A Handbook of Agile Software Craftsmanship

Thu, 13 Aug 2009 00:00:00 +0000

For my summer holidays i needed a book that was easy readable (size, weight, content) and Clean Code: A Handbook of Agile Software Craftsmanship was a perfect match for my reading sessions at the pool. Even better, i found inspiration to write cleaner (and thus better) code. This book is most certainly recommend!

Experimenting with ControlStateMachine and Fluent interfaces

Thu, 13 Aug 2009 00:00:00 +0000

A long time ago i read Build your own CAB series and recently i noticed that there is a wiki: Presentation Patterns Wiki! and it inspired me to experiment with state machines. Here are a couple of examples:

controlStateMachine = new ControlStateMachine<states>(this);

controlStateMachine.AfterEachStateChange()
.Do(MakeRelevantButtonsVisible);

controlStateMachine.WhenStateChangesTo(States.RetrievingSubscriptionPeriod)
.TheOnlyVisibleControlsAre(flowLayoutPanel1, datePicker1);

controlStateMachine.WhenStateChangesTo(States.RetrievingCustomerInformation)
.MakeVisible(customerInput1)
.Do(() => customerInput1.Dock = DockStyle.Fill);

controlStateMachine.WhenStateChangesTo(States.Ready)
.MakeInvisible(customerInput1);

And here is another example:

wizardStateMachine = new WizardStateMachine<states>(controlStateMachine);

wizardStateMachine.InState(States.RetrievingSubscriptionPeriod)
.OnCommand(WizardCommands.Next)
.TransitionTo(States.RetrievingCustomerInformation);

wizardStateMachine.InState(States.RetrievingCustomerInformation)
.OnCommand(WizardCommands.Back)
.TransitionTo(States.RetrievingSubscriptionPeriod)
.OnCommand(WizardCommands.Finish)
.TransitionTo(States.Ready);

wizardStateMachine.InState(States.Ready)
.OnCommand(WizardCommands.New)
.Do(() => MessageBox.Show("Currently not supported"));

Stay tuned for future posts where i describe the problem space that have lead to this API.

Iconoclast: A Neuroscientist Reveals How to Think Differently

Mon, 13 Jul 2009 00:00:00 +0000

Because i really enjoyed managing humans i bought another book mentionned by Joel Spolsky: Iconoclast: A Neuroscientist Reveals How to Think Differently. This book would be an excellent read at the pool on a holiday location, but at home it was nothing more than an entertaining read. Not really recommended.

Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions

Sat, 11 Jul 2009 00:00:00 +0000

A while ago we had a session on messaging at ALT.NET Belgium and it was then that i decided i should order my copy of Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions. I found first half of the book pretty interesting but got bored around chapter 8 and skipped some sections from there. All in all this book this book is pretty good and if you know a thing or two about TCP/IP implementations you might even recognize some patterns in a different problem space.

Small modification to achieve better modularity with Prism

Sat, 11 Jul 2009 00:00:00 +0000

I have been experimenting with WPF and Prism (Composite Application Guidance for WPF and Silverlight) and ran into a major issue: modularity. Here is an excerpt from the documentation

Modules have explicit boundaries, typically by subsystem or feature. Having these boundaries makes it easier for separate teams to develop modules. On large applications, teams may be organized by cross-cutting capabilities in addition to being organized by a specific subsystem or feature. For example, there may be a team assigned to shared components of the application, such as the shell or the common infrastructure module.

Beyond the basics: IPropertyAccessor

Sat, 27 Jun 2009 00:00:00 +0000

Consider the following classes: an abstract Account and a concrete SavingAccount

abstract class Account
{
	int Id { get; protected set; }
	int CustomerId { get; protected set; }
	abstract AccountType Type { get; }
}

class SavingAccount : Account, ISavingAccount
{
	private SavingAccount() { }
	public SavingAccount(int customerId) { CustomerId = customerId; }
	public override AccountType Type { get { return AccountType.SavingAccount; } }
}

And this is the schema on which we want to map these classes

We define a Fluent NHibernate mapping as following:

public class AccountMap : ClassMap<account>
{
	public AccountMap()
	{
		WithTable("Accounts");
		Id(a => a.Id).ColumnName("account_id");
		Map(a => a.CustomerId).ColumnName("customer_id");
		Map(a => a.Type).ColumnName("account_type");
		SetAttribute("lazy", "false");

		JoinedSubClass<savingAccount>("saving\_account\_id", MapSavingAccount);
	}

	public void MapSavingAccount(JoinedSubClassPart<savingAccount> jscp)
	{
		jscp.WithTableName("SavingAccounts");
		jscp.SetAttribute("lazy", "false");
	}
}

As soon as we try to use this mapping we run into an “Could not find a setter for property ‘Type’ in class ‘Banking.Domain.CheckingAccount” exception. A quick look with reflector teaches us there are a couple of strategies, but none of them suits our needs.

VS2010: Unable to insert a breakpoint by clicking next to the line number

Tue, 16 Jun 2009 00:00:00 +0000

For some reason i was unable to insert a breakpoint by clicking next to the line number in VS2010. Anyway, here is the trick that made the problem disappear for me: Go to “Tools > Import and export settings… " and choose “Reset all settings”.

Adding items to SendTo folder

Sun, 07 Jun 2009 00:00:00 +0000

When i tried to access the SendTo folder i got a message box saying: “Access is denied”.

A bit of searching thought me that the folder can be accessed via the “shell:sendto” command.

And now i can add a shortcut to Notepad2 which i use to inspect a Visual Studio solution or project file.

First thoughts about Windows 7

Sat, 06 Jun 2009 00:00:00 +0000

It is almost two years ago that i decided to uninstall Vista after a bad first impression. Nowadays i have learned to live with it, but i guess i will never understand what all the fuss was about.

I can imagine that the marketing department will generate a lot of noise about Windows 7 but i am not convinced that there are actually people waiting for yet another OS. Anyway, i installed Windows 7 somewhere last week and i must say that i am pretty pleased with it. I guess that you didn’t see that one coming, do you? Me, finally liking an operation system that comes from Microsoft 😉

Using the Do handler for a method with out parameters

Mon, 25 May 2009 00:00:00 +0000

As you can read in the documentation for Rhino Mocks:

There are times when the returning a static value is not good enough for the scenario that you are testing, so for those cases, you can use the Do() handler to add custom behavior when the method is called. In general, the Do() handler simply replaces the method call. Its return value will be returned from the mocked call (as well as any exception thrown). The handler’s signature must match the method signature, since it gets the same parameters as the call.

Measuring elapsed time

Sat, 16 May 2009 00:00:00 +0000

As the documentation for System.Diagnostics.Stopwatch says

In a typical Stopwatch scenario, you call the Start method, then eventually call the Stop method, and then you check elapsed time using the Elapsed property.

I find it a shame that they didn’t provide a method that covers this particular scenario so i did it myself

public static class Stopwatch
{
	public static TimeSpan Measure(this Action action)
	{
		var stopwatch = new System.Diagnostics.Stopwatch();
		stopwatch.Start();
		action.Invoke();
		stopwatch.Stop();
		return stopwatch.Elapsed;
	}
}

Consuming this method is as simple as

Sparkles

Tue, 05 May 2009 00:00:00 +0000

In my opinion Pieter Gheysens is one of those persons that has contributed something valuable to the Belgian .Net community: Great Visug sessions and some interesting courses at Compuware so i shamelessly plug his new company Sparkles here. Now go and find out how they can make you a better developer!

Easy deployment through virtualisation

Sun, 03 May 2009 00:00:00 +0000

A couple of years ago, i think somewhere in 2003, i realised that hardware virtualisation was the way to go. Whenever i talked with people about distributing and deploying applications with a virtual machine image instead of a traditional installer they laughed at me (or atleast gave me a strange look of disbelief). The availability of multiple machines can be represented in a windowing environment through a metaphor of multiple desktops. Anyway, i’m still convinced that there will be a point in time where users have access to multiple applications that run in their own virtual machine. Time will tell.

Enterprise Service Bus

Sun, 03 May 2009 00:00:00 +0000

I believe it was at an Alt.Net meeting that the Enterprise Service Bus book was mentionned and i recently decided to give it a read. This book covers everything there is to know about an ESB. From a developer point of view it can serve as a good introduction to the core components and applied patterns but nothing more.

Beautiful Code: Leading Programmers Explain How They Think

Sat, 25 Apr 2009 00:00:00 +0000

Beautiful Code: Leading Programmers Explain How They Think is another book that i started reading a couple of weeks ago. A couple of chapters were pretty interesting but i skipped the parts with large chunks of code because i get bored with code in books. Code should be read on a computer display in an editor! Despite many others, i can’t say that this book was worth it.

Reading this book made me realize that posting large chunks of code in a blog post is boring too. So i have decided to write more about ideas and concepts instead of code.

Essentials of Organizational Behavior

Sat, 25 Apr 2009 00:00:00 +0000

Somewhere in 2007 I started reading Essentials of Organizational Behavior and only finished it earlier this week. This book covers behavior of humans, humans in organizations, and organizations. Although the book covers the topics pretty well i must say that i liked Managing Humans: Biting and Humorous Tales of a Software Engineering Manager more.

Mastering regular expressions

Sat, 25 Apr 2009 00:00:00 +0000

A regular expression is a domain specific language for identifying parts in text and is one of those things every software developer should have learned. I ordered my copy of Mastering regular expressions way back in 2001 and found it incredibly good! Allthough there are books that cover a specific dialect better, i still think this book is recommended because it also teaches the reader to read regular expressions.

Pondering about code generation

Sat, 18 Apr 2009 00:00:00 +0000

A while ago i was listening to ‘Kathleen Dollard on MEF and More’ on NET Rocks! and it got me thinking.

For a long time i considered code generation as a way to reduce the tedious parts of software development by spitting out considerable amounts of code and I immediately thought of tools like T4: Text Template Transformation Toolkit and GAT: Guidance Automation Toolkit.

I believe that in order to become more productive we need a solution that requires less code spitting by means of better frameworks and higher languages. Eg: C# allows us to think about computer instructions on a much higher level than assembly language.

Managing Humans: Biting and Humorous Tales of a Software Engineering Manager

Sat, 04 Apr 2009 00:00:00 +0000

A while ago i heared Joel Spolsky shamelessly promote Managing Humans: Biting and Humorous Tales of a Software Engineering Manager and decided to give it a read. No boring process descriptions, but short and consice chapters, fed with real life examples, transmitting the message to the reader. I loved reading this book.

POC: Moq API adapter for Rhino Mocks

Fri, 03 Apr 2009 00:00:00 +0000

One of my main concerns with third party software, and software in general, is maintainability. The Rhino Mocks project has been out there for a couple of years now and i’m pretty confident that it won’t go away anytime soon. The Moq project is a lot younger and will have to proove that it can stay alive…

Anyway, because most people seem to digg the Moq API i have decided to write an adapter that provides the same API using Rhino Mocks. Here are some simple examples

xUnit Test Patterns: Refactoring Test Code

Sat, 28 Mar 2009 00:00:00 +0000

xUnit Test Patterns: Refactoring Test Code starts with narratives on philosophy, principles, strategies and test smells. The second part covers test smells but i skimmed through these chapters because i have already had the joy to experience these anti-patterns first hand 🙁 Most chapters in the third part, covering actual patterns, caught my attention and inspired me. Although it’s quite big, 700+ pages, this book is most certainly recommended!

Strict mocks lead to overspecification

Tue, 24 Mar 2009 00:00:00 +0000

Here is an example that demonstrates how strick mocks lead to overspecification. Imagine that we are creating a simple screen in a Passive View architecture. The first feature that we implement is displaying the message “edit” when the user clicks the edit button

[Fact] public void ShouldDisplayEditClickMessage()
{
	// Establish context
	MockRepository mockRepository = new MockRepository();
	IView view = mockRepository.StrictMock<iview>();
	Expect.Call(delegate { view.EditClick += null; }).IgnoreArguments();
	mockRepository.Replay(view);

	// Create sut
	Presenter sut = new Presenter(view);

	// Setup expectations
	mockRepository.BackToRecord(view, BackToRecordOptions.Expectations);
	Expect.Call(delegate { view.DisplayClickMessage("edit"); });
	mockRepository.ReplayAll();

	// Exercise
	RhinoMocksExtensions
	.GetEventRaiser(view, delegate(IView v) { v.EditClick += null; })
	.Raise(view, EventArgs.Empty);

	// Verify
	mockRepository.VerifyAll();
}

Comparing Moq to Rhino Mocks

Mon, 23 Mar 2009 00:00:00 +0000

So which mocking framework should we use? Do we fall back on good old Rhino Mocks or do we choose for the new kid on the block Moq?

From a technical point of view i would dare to say that they will be able to support the same set of features because they’re both based on Castle’s DynamicProxy. Rhino Mocks has the advantages that it, unlike Moq, supports the mocking of Delegates and can be used in a .Net 2.0 only environment. Whether or not we should care about these differences is a question i will leave unanswered.

Getting started with Moq

Sat, 21 Mar 2009 00:00:00 +0000

In this article I will demonstrate the Moq API by means of a simple application that allows the user to manage a quote.

In order to prevent that we have to rewrite our application when we move to a different graphical environment such as Web Forms, Silverlight or WPF I have decided to apply the [Humble Object](http://xunitpatterns.com/Humble Object.html) pattern in the design. The implementation of the application has been based on the Passive View pattern.

Another reason for not using mstest

Sat, 14 Mar 2009 00:00:00 +0000

As you can read in CA1001: Types that own disposable fields should be disposable. Pretty solid advice, but for some reason the mstest runner does not dispose of classes that implement IDisposable. A possible workaround is to apply a TestCleanupAttribute to the Dispose method, but this is really contradictory with the “Shared test fixture” approach mstest uses. Imho, there is only one clean solution: use a decent testing framework instead.

Setup expectation with successive function calls using Moq

Sat, 14 Mar 2009 00:00:00 +0000

In the Quickstart guide we find an example that shows us how to setup a different return value for each invocation as following

// returning different values on each invocation
var mock = new Mock<ifoo>();
var calls = 0;
mock.Setup(foo => foo.Execute("ping"))
	.Returns(() => calls)
	.Callback(() => calls++);
// returns 0 on first invocation, 1 on the next, and so on
Console.WriteLine(mock.Object.Execute("ping"));

In Moq Triqs – Successive Expectations i found inspiration to implement an extension method that allows me to define an expectation that calls a set of successive functions

Using sed

Thu, 05 Mar 2009 00:00:00 +0000

For a couple of days now i’ve been pondering about posting something about my love for GNU text-utilities but never got round to it. A couple of minutes ago i read Phil Windley’s Using Grep and Find post so here is a one-liner that shows how you can add a reference to a msbuild target file to all csproj files in a given folder:

find -name *.csproj -exec sed -i -e '#^</project>$# <import Project="X:\\BuildTasks\\Corp.targets" />\r\n</project>' {} \;

Or if you are frustrated with System.Diagnostics.CodeAnalysis.SuppressMessageAttributes and want to remove them from all your cs files:

NHibernate in Action

Mon, 23 Feb 2009 00:00:00 +0000

Last week i received my copy of NHibernate in Action. This book provides much more than the typical examples you find in the product documentation like architectural guidance on the application of O/R Mapping. Even with my Hibernate experience i found some interesting insights in the NHibernate features. This book is most certainly recommended!

JavaScript: The Good Parts

Fri, 13 Feb 2009 00:00:00 +0000

This week i have been reading JavaScript: The Good Parts. Although the book is pretty thin, approximitaly. 150 pages, the information that is inside the book is really powerful. The book provides deep insight for people that are considering to implement functionality in JavaScript. I would say that this is a must read.

Here is an example of something that i learned from the book (A workaround for an error in the ECMAScript Language Specification which causes this to be set incorrectly for inner functions)

Microsoft .NET: Architecting Applications for the Enterprise

Fri, 13 Feb 2009 00:00:00 +0000

Earlier this month i have read Microsoft .NET: Architecting Applications for the Enterprise. This time i was pretty pleased to notice that the author, Dino Esposito, did not fill the book with references to other books written by him. All in all the book painted a pretty accurate picture of enterprise application development that is obviously inspired by masterworks like: Design Patterns: Elements of Reusable Object-Oriented Software, Patterns of Enterprise Application Architecture and Domain-Driven Design: Tackling Complexity in the Heart of Software.

Non-Designer's Design Book

Fri, 13 Feb 2009 00:00:00 +0000

A couple of weeks ago the Non-Designer’s Design Book was mentionned in some podcast i was listening to and i decided to give it a read. The author has stuffed the color printed book with examples describing the four basic design principles:

Contrast: The idea behind contrast is to avoid elements on the page that are merely similar. If the elements (type, color, size, line thickness, shape, space, etc.) are not the same, then make them very different. Contrast is often the most important visual attraction on a page.
Repetition: Repeat visual elements of the design throughout the piece. You can repeat color, shape, texture, spatial relationships, line thicknesses, sizes, etc. This helps develop the organization and strengthens the unity.
Alignment: Nothing should be placed on the page arbitrarily. Every element should have some visual connection with another element on the page. This creates a clean, sophisticated, fresh look.
Proximity: Items relating to each other should be grouped close together. When several items are in close proximity to each other, they become one visual unit rather than several separate units. This helps organize information and reduces clutter.

The art of Unit Testing

Mon, 29 Dec 2008 00:00:00 +0000

This weekend i have been reading The art of Unit Testing via the Manning Early Access Program. This book does not really teach you how to write unit tests but tries to answer those questions you start asking yourself after a while: How can i organize my tests? How do i make sure they are maintainable? Although the book is not loaded with new concepts, the existing ones are well covered. Probably one of the first books in this genre for the .Net world and most certainly recommended for reading.

Programming Microsoft ASP.NET 2.0 Applications: Advanced Topics

Sat, 27 Dec 2008 00:00:00 +0000

Although i was most of the week in bed with a cold i managed to finish reading Programming Microsoft ASP.NET 2.0 Applications: Advanced Topics. This book contained less references to the previous book (luckily, because that one has been superseded now). I found it a bit confusing when the author explained half of a topic, diversified to something completely different, and then finished the topic. If you want some more insight in the ASP.NET machinery this book is recommended. What i did miss is a section on the inner workings of View State and change tracking but i have yet to find a book that covers this topic.

Presenting MyTestRunner

Wed, 24 Dec 2008 00:00:00 +0000

Here are a couple of reasons why i dislike the Unit Testing Framework that comes with Visual Studio Team System:

Not all versions of Visual Studio are capable of running the tests.
Test inheritance is not supported.
Running tests via mstest.exe is slow.
Visual Studio creating tens of .vmsdi files.

There are already a couple of better frameworks out there, and currently MbUnit is my favorite one, certainly in combination with TestDriven.NET.

I have created a custom implementation of the Microsoft.VisualStudio.QualityTools.UnitTestingFramework assembly. Actually, the assembly only has a couple of Attributes for the moment but contributions are always welcome 😉

Applying Domain-Driven Design and Patterns: With Examples in C# and .NET

Mon, 22 Dec 2008 00:00:00 +0000

In his book, Applying Domain-Driven Design and Patterns: With Examples in C# and .NET, Jimmy Nilsson covers the most common questions you ask yourself when you are thinking about applying DDD to one of your projects. Sometimes i found the ordering of the chapters a bit odd but all in all it was an excellent read and most certainly recommended.

Exploring AJAX on the ASP.NET platform

Sun, 14 Dec 2008 00:00:00 +0000

I finally found some time to experiment with AJAX on the ASP.NET platform. The first technique i looked into was Partial-Page Rendering with controls like UpdatePanel. It gave me an awkward feeling but even Dino Esposito, who spent a whole chapter on this technique in his book, seems to share that feeling.

Page methods, public static methods that are decorated with the WebMethodAttribute declared on a Page are exposed as a WebService method and return the result as JSON. An easy solution but it comes with the cost that it does not offer much flexibility.

Programming Microsoft ASP.NET 3.5

Sun, 14 Dec 2008 00:00:00 +0000

Having heared only positive things about Dino Esposito’s way of writing i decided to read Programming Microsoft ASP.NET 3.5. The book is written in a way that invites you to read and experiment with the contents. It covered the essentials of ASP.NET programming but i did not have the feeling that it added much to what i had read in Professional ASP.NET 2.0. After a while i became annoyed with the numerous references to Programming Microsoft ASP.NET 2.0 Applications: Advanced Topics.

Release It!: Design and Deploy Production-Ready Software

Sat, 22 Nov 2008 00:00:00 +0000

I really loved reading The Pragmatic Programmer: From Journeyman to Master from The Pragmatic Programmers so when i noticed that a couple of bloggers were recommending Release It!: Design and Deploy Production-Ready Software i decided to read it too. This book covers what happens to an application after it has been deployed in production. I really appreciated the first chapters with anti-patterns and patterns. At the end of the book the author also touches the problem of dependencies between machines and deployed applications and briefly offers a management solution under the name OpsDb. All in all, this book made me conscient about a set of problems i would not think about otherwise.

Query a specific Google Calendar

Wed, 22 Oct 2008 00:00:00 +0000

Despite the multiple copies of the API Developer’s Guide: .NET i found i was unable to find how i should query a specific calendar (not the default). Anyway, it can be done by using the CalendarEntry.Content.BaseUri as the query uri. Here is an example

public class CalendarHelper
{
	public const string OwnedCalendarsUrl = "http://www.google.com/calendar/feeds/default/owncalendars/full";

	private readonly CalendarService svc;

	public CalendarHelper(string username, string password)
	{
		this.svc = new CalendarService("demo");
		this.svc.setUserCredentials(username, password);
	}

	public IEnumerable<calendarEntry> FindOwnedCalendars()
	{
		CalendarQuery query = new CalendarQuery(OwnedCalendarsUrl);
		CalendarFeed result = this.svc.Query(query);
		foreach (CalendarEntry entry in result.Entries) yield return entry;
	}

	public CalendarEntry GetCalendar(string name)
	{
		return (
			from calendar in this.FindOwnedCalendars()
			where calendar.Title.Text == name
			select calendar).SingleOrDefault();
	}

	public IEnumerable<atomEntry> FindEvents(CalendarEntry calendar, DateTime begin, DateTime end)
	{
		EventQuery myQuery = new EventQuery(calendar.Content.AbsoluteUri);
		myQuery.StartTime = begin;
		myQuery.EndTime = end;
		EventFeed result = this.svc.Query(myQuery);
		for (int i = 0; i < result.Entries.Count; ++i) yield return result.Entries[i]; 
	} 
} 

private static void Main() 
{ 
	CalendarHelper helper = new CalendarHelper("user@gmail.com", "xxx"); 
	DateTime begin = new DateTime(2008, 1, 1); 
	DateTime end= new DateTime(2009, 12, 31); 
	IEnumerable<calendarEntry> calendars = helper.FindOwnedCalendars();
	
	foreach (CalendarEntry calendar in calendars)
	{
		Console.WriteLine(calendar.Title.Text);

		IEnumerable<atomEntry> calendarEvents = helper.FindEvents(calendar, begin, end);
		foreach(AtomEntry calendarEvent in calendarEvents)
		{
			Console.WriteLine("{0}: {1}", calendarEvent.Updated, calendarEvent.Title.Text);
		}

		Console.WriteLine();
	}

	Console.Write("{0}Press any key to continue...", Environment.NewLine);
	Console.ReadKey();
}

Refactoring Application Environment (Part 2)

Fri, 17 Oct 2008 00:00:00 +0000

Luca Milan notified me of a design issue. Until now the ApplicationEnvironment had an Instance property as following:

public static ApplicationEnvironment Instance { get { ... } }

A lot of flexibility can be added by extracting an interface IApplicationEnvironment and use that as return type for the property:

public static IApplicationEnvironment Instance { get { ... } }

Now that we have Common Service Locator i have decided to completely remove the Instance property. Code that requires an instance of the IApplicationEnvironment will have to resolve it via the ServiceLocator:

How does the controller know which action method to invoke?

Wed, 15 Oct 2008 00:00:00 +0000

Yesterday i attended another great VISUG event on ASP.NET presented by Maarten Balliauw. He demonstrated a custom filter but did not dig into the mechanics of action method resolving. With the aid of of the ActionName attribute we can map different methods to the same action. The following methods will all map to the same “Detail” action

public ActionResult Detail(int productId) { ... }
public ActionResult Detail(int productId, string name) { ... }
[ActionName("Detail")] public ActionResult DisplayDetail(int productId) { ... }
[ActionName("Detail")] public ActionResult ModifyDetail(int productId, string name) { ... }

So how does the Controller know which method to invoke? The answer can be found in the ActionMethodSelector which tries to find the method as following

Adaptive control behavior: LinkButton without javascript

Tue, 14 Oct 2008 00:00:00 +0000

‘Experiment with Adaptive Control Behavior’ has been an item on my TO-DO list for a very long time and this weekend i finally found some time to do exactly that. Because i hate it that a LinkButton renders as i decided to develop a ControlAdapter that makes the LinkButton work without JavaScript. While i was at it i also wrote adapters for the LoginStatus and Login controls. Feel free to play with the Adaptive Rendering Demo.

Revisited the int and string ValueObject templates

Mon, 13 Oct 2008 00:00:00 +0000

After reading The Compare Contract last week i realized that my templates for int and string ValueObjects did not comply with the contract so i decided to add a unittest that reproduces the faulty behavior (and then corrected the implementation)

[TestMethod]
public void ShouldReturnPositiveWhenComparedWithNull()
{
	$classname$ value = new $classname$("0");
	Assert.IsTrue(value.CompareTo(null) > 0);
}

Anyway, feel free to download the corrected IntValueObject and StringValueObject templates.

The Best Damn Windows Server 2003 Book Period

Mon, 06 Oct 2008 00:00:00 +0000

Last week i have read The Best Damn Windows Server 2003 Book Period. Although the book contains some interesting guidance i became annoyed with the fact that the book is overloaded with screenshots. Without those screenshots this book would contain around 250 interesting pages.

Experimenting with NDepend

Sat, 27 Sep 2008 00:00:00 +0000

Google Reader found 122 posts in my blogroll about NDepend so i happily accepted the professional license which Patrick Smacchia (thank you) offered me earlier this week. I quickly picked the assemblies from a project that has evolved over more than 5 years (.NET 1.0, 1.1 and 2.0) and the tool generated a screen loaded with data, but i found it difficult to extract any valuable information out of the statistics. Although i found zooming in the UI impressive, i was a bit disappointed.

.NET System Management Services

Fri, 26 Sep 2008 00:00:00 +0000

Earlier this week i finished reading .NET System Management Services. Although the book was published back in 2003, it still contains a lot of useful information on using the classes in the System.Management namespace. I did not like the fact that the author really made the effort to explain each line of code in the book. On the other hand, the book contains a lot of useful tips that help with writing WMI queries, generating managed classes around WMI classes (and objects) and even applications that query SNMP via WMI. All in all, i can recommend the book if you are going to use the System.Management API.

Presenting templates for int and string ValueObjects

Fri, 26 Sep 2008 00:00:00 +0000

Most ValueObjects that i have implemented were wrappers around an int or a string. Apart from the domain specific rules, there is a lot of repetitive work in implementing operator overloads, IEquatable, IComparable, … Thus i decided to create a couple of Item templates that generate this code (and related tests).

Simply save IntValueObject.zip and StringValueObject.zip under %My Documents%\Visual Studio 2005\Templates\ItemTemplates and click on “Add New Item” in your project:

Why MockRepository does not implement IDisposable

Fri, 26 Sep 2008 00:00:00 +0000

Earlier this week i was experimenting with Rhino Mocks and i was wondering why the MockRepository does not implement IDisposable unlike most other mocking frameworks for .NET. After a bit of searching i found out that (here) originally the MockRepository did implement the interface, but that the implementation was removed because it is can be painful (hiding the original exception) when unexpected exceptions are thrown.

I really like the API. Here is a simple example and notice that i did not have to provide the method name (as in the string “GetTime”) for the excepted calls.

Refactoring ApplicationEnvironment

Tue, 23 Sep 2008 00:00:00 +0000

Yesterday i blogged about an ApplicationEnvironment which had a dependency on the application configuration file. With my ConfigurationFileSession i was able to test the implementation despite that dependency. Today i modified the design a little so that i do not require the ConfigurationFileSession hack anymore.

First i added an internal constructor as following

internal protected ApplicationEnvironment(DateTime instanceEpoch, DateTime applicationEpoch)
{
	this.instanceEpoch = instanceEpoch;
	this.applicationEpoch = applicationEpoch;
}

Then i made the internals visible to the test project

Refactoring EffectivityManager

Tue, 23 Sep 2008 00:00:00 +0000

A while ago i presented the EffectivityManager. Having used this class for a while i have decided to rename it to Temporal. The implementation of IList is not required anymore because a user is typically only interested in a specific effectivity, not the evolution of the effectivities.

public interface ITemporal<T>
{
	void Modify(T element, DateTime from);
	IEffectivity<T> GetSnapshot(DateTime validityDate);
	bool TryGetSnapshot(DateTime validityDate, out IEffectivity<T> effectivity);
}

In the implementation i have added a constructor that accepts a DiscreteValuesGenerator which makes it possible to create Periods with a resolution of a day instead of seconds.

Presenting ApplicationEnvironment

Mon, 22 Sep 2008 00:00:00 +0000

Imagine we are an ice cream vendor. During summer months our available capacity is twice as high as in the rest of the year. In code this problem looks like the following

public int AvailableCapacity
{
	get
	{
		DateTime now = DateTime.UtcNow;

		if (new DateTime(now.Year, 6, 1) <= now && now <= new DateTime(now.Year, 9, 1) ) { return 10000; } 
		else { return 5000; } 
	} 
}

This code is pretty difficult to test because it depends on DateTime.UtcNow. In order to get control over that dependency i have defined an ApplicationEnvironment and rewritten the code as following

Presenting ConfigurationFileSession

Mon, 22 Sep 2008 00:00:00 +0000

Here is a little class that allows you to use different configuration files. I find it extremely useful for tests where i want to mock the values that would be retrieved via the ConfigurationManager. Here are a couple of examples how it can be used

[TestMethod]
public void ShouldUseSystemTimeWhenNoValuesAreProvided()
{
	using (new ConfigurationFileSession("WithoutDateTimeManipulation.config"))
	{
		ApplicationEnvironment.Instance.Refresh();

		DateTime now = DateTime.UtcNow;
		TimeSpan allowedDifference = TimeSpan.FromSeconds(1);
		TimeSpan actualDifference = ApplicationEnvironment.Instance.CurrentDateTime -- configurationNow;
		Assert.IsTrue(actualDifference < allowedDifference); 
	} 
} 
		
[TestMethod] 
public void ShouldUseValuesAsProvided() 
{ 
	using (new ConfigurationFileSession("WithDateTimeManipulation.config")) 
	{ 
		ApplicationEnvironment.Instance.Refresh(); 
		DateTime now = new DateTime(2000, 1, 1); 
		TimeSpan allowedDifference = TimeSpan.FromSeconds(1); 
		TimeSpan actualDifference = ApplicationEnvironment.Instance.CurrentDateTime - configurationNow; 
		Assert.IsTrue(actualDifference < allowedDifference); 
	} 
}

Feel free to download the code from BeTimvwFramework.

Visual Studio 2008 (SP1) crashes when opening ViewPage in designer

Tue, 16 Sep 2008 00:00:00 +0000

Visual Studio 2008 (SP1) crashed every time i tried to open a ViewPage with the Web Form Editor (designer). Kudos go to eniac who suggested the removal of the Power Commands add-in. This made the crashes disappear.

Presenting a couple of custom MarkupExtensions

Wed, 10 Sep 2008 00:00:00 +0000

XAML provides us a way to declare objects with xml. Because i don’t want to clutter my domain classes with attributes like TypeConverterAttribute, i needed a different approach to manipulate the parsing. This is where custom MarkupExtensions come to the rescue. Here is an example where i use the x:Array MarkupExtension in order to load a list of Lines into my IList Lines property

<?xml version="1.0" encoding="utf-8" ?>
<d:Address xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:d="clr-namespace:XamlDemo.Domain;assembly=XamlDemo" xmlns:e="clr-namespace:XamlDemo.Infrastructure.Extensions;assembly=XamlDemo">
	<d:Address.Lines>
		<x:Array Type="s:String">
			<s:String>Ikaroslaan 21</s:String>
			<s:String>B-1930 Zaventem</s:String>
		</x:Array>
	</d:Address.Lines>
</d:Address>

By default all XAML documents have all the data embedded. Sometimes this is undesirable so i decided to define External and ExternalList MarkupExtensions that allow us to specify that the resource is elsewhere available. Here is an example of Jeff who has one address in a different file, Domain\Address\Leuven\Brusselsestraat_400.xaml

Distributed Data Applications with ASP.NET, Second Edition

Sat, 06 Sep 2008 00:00:00 +0000

Last week i finally got round to reading Distributed Data Applications with ASP.NET, Second Edition. The book was written in 2004 and handles technologies like HTML Applications and XMLHttpRequest. Although the book is loaded with code, it also contains plenty of reasoning behind the choice of one approach over another which made me appreciate the book. Definitely worth the 1.5 euros i paid for it.

Presenting WindowsIdentityHelper

Sat, 06 Sep 2008 00:00:00 +0000

One of the difficulties of using the WindowsIdentity class is the fact that it requires a handle (IntPtr) to a Windows Security Token. Using the LogonUser functionality we can get a hold of such a handle

[DllImport(Advapi32File, CharSet = DefaultCharSet, SetLastError = DefaultSetLastError)]
public static extern bool LogonUser( /* other parameters */, out IntPtr userTokenHandle);

The easiest way to avoid memory leaks is to implement a custom SafeHandle

public class SafeTokenHandle : SafeHandleZeroOrMinusOneIsInvalid
{
	protected internal SafeTokenHandle()
	: base(true)
	{
	}

	protected override bool ReleaseHandle()
	{
		if(!this.IsInvalid)
		{
			return NativeMethods.CloseHandle(this.handle);
		}

		return true;
	}
}

With that SafeHandle in place we can change the signature to

Experimenting with naming conventions for unit tests

Fri, 05 Sep 2008 00:00:00 +0000

To be honest, i never really took the time to think about the names of my unit tests. Although i noticed posts like this one and this one they never inspired me to think about it. Earlier this week, Yves Goeleven demonstrated the power of using BDD inspired naming conventions and i was immediately sold. I applied the style on a couple of tests in BeTimvwFramework and i must say that i like the resulting tests:

The Microsoft Certified Professional Developer: Enterprise Applications Developer on Visual Studio 2005

Fri, 05 Sep 2008 00:00:00 +0000

Not that anyone should care, apart from my manager, i posted that the only remaining exam was 070-549 PRO: Designing and Developing Enterprise Applications by Using the Microsoft .NET Framework a while ago. And this morning i passed that exam 🙂 This means that i have earned the “MCPD: Enterprise Applications Developer” certificate that demonstrates that i have the comprehensive skills required to build n-tier solutions that target both Web and client user experiences.

Presenting AssemblyTypePicker

Mon, 01 Sep 2008 00:00:00 +0000

I really like the way the Object Browser makes the types in an assembly visible. Because i have a couple of programs that require a given type as input, i have decided to add a TypeTree control to BeTimvwFramework that mimicks the Object Browser. Here are a couple of screenshots of the control in a demo application that allows the user to generate interfaces and wrapper classes based on a selected type:

Presenting EventHandlerHelper

Mon, 01 Sep 2008 00:00:00 +0000

Being bored of writing code to raise an event, i have added an EventHandlerHelper to BeTimvwFramework.

public static class EventHandlerHelper
{
	[MethodImpl(MethodImplOptions.NoInlining)]
	public static void Raise<T>(EventHandler<T> handler, object sender, T e) where T : EventArgs
	{
		if (handler != null)
		{
			handler(sender, e);
		}
	}
}

Presenting ItemEventArgs

Mon, 01 Sep 2008 00:00:00 +0000

Because i believe in the DRY principle i decided to add a generic ItemEventArgs class to BeTimvwFramework

public class ItemEventArgs<T> : EventArgs
{
	private T item;

	public ItemEventArgs(T item)
	{
		this.item = item;
	}

	public T Item
	{
		get { return this.item; }
		set { this.item = value; }
	}
}

Presenting OneTimePasswordMembershipProvider

Fri, 29 Aug 2008 00:00:00 +0000

What good is a TimeOTP client if you don’t have anything to use it with? Last week i have implemented a MembershipProvider that uses Time-based One-Time Password to validate the user credentials. Basically, it is a wrapper around an existing MembershipProvider, you get to choose which one via the providerType attribute in the configuration, and requires that it can access the password of users. Here is an example configuration that relies on the SqlMembershipProvider

Presenting TimeOTPClient

Sat, 23 Aug 2008 00:00:00 +0000

Because most people have their java enabled mobile phone with them, and I did not want to buy an expensive token generator I decided to write a MIDlet that can generate passwords as specified in the TOTP algorithm. This project is build with Sun Java Wireless Toolkit for CLDC. Feel free to download the sources, TimeOTPClient.zip.

Presenting HMAC-Based OTP and Time-Based OTP

Fri, 22 Aug 2008 00:00:00 +0000

I could not find a .NET implementation of the HMAC-Based One Time Password (HOTP) algorithm as specified in RFC4226 so i decided to write one myself. Because the Time-Based OTP (TOTP) algorithm is an application of HOTP, more specifically: TOTP = HOTP(K, T) with T = (Current Unix time – T0) / Timestep, i have implemented that algorithm too.

You can find both Be.Timvw.Framework.Security.HmacOneTimePassword and Be.Timvw.Framework.Security.TimeOneTimePassword in the BeTimvwFramework. For more information about authentication i would recommend the specifications and technicals resources at the OATH.

Presenting TimeSpanHelper

Wed, 20 Aug 2008 00:00:00 +0000

A TimeSpan is a structure that represents a time interval or a duration. To make the everything as clear as possible, a well designed system should not only know the quantity, but also the unit of that quantity. In order to create a TimeSpan that represents the right value, you will probably use one of the FromXXX (Hours, Days, Minutes, Seconds) methods as following

double value = 1;
string unit = "Day";

TimeSpan actual;
if (unit == "Day")
{
	actual = TimeSpan.FromDays(value);
}
else if (unit == "Hour")
{
	actual = TimeSpan.FromHours(value);
}
// more else if statements...

After a while you get bored of writing that same if-else (or switch) construct and you end up wishing for something like

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