Reading MSMQ contents with Powershell

This article will present two ways to read a MSMQ (Microsoft Message Queue) using Powershell. First, the queue will be read using the GetString method of System.Text.UTF8Encoding:

[System.Reflection.Assembly]::LoadWithPartialName("System.Messaging") | Out-Null
 
$queuePath = ".\private$\myqueue"

$queue = New-Object System.Messaging.MessageQueue $queuePath

foreach ($message in $queue.GetAllMessages()){

 Write-Host (New-Object System.Text.UTF8Encoding).GetString($message.BodyStream.ToArray())

 Write-Host $msg 
}

As an alternative, it is also possible to use the StreamReader (more ceremony really):

[System.Reflection.Assembly]::LoadWithPartialName("System.Messaging") | Out-Null
 
$queuePath = ".\private$\myqueue"

$queue = New-Object System.Messaging.MessageQueue $queuePath

foreach ($message in $queue.GetAllMessages()){

 Write-Host ([Environment]::NewLine)

 $sr = New-Object System.IO.StreamReader($message.BodyStream)

 $message.Formatter = New-Object System.Messaging.XmlMessageFormatter(@(""));
 
 $msg = "";

 while ($sr.Peek() -ge 0){
  $msg += $sr.ReadLine()
 }

 Write-Host $msg 
}

Actually, I was needing a simple way to look at some messages sent with the NetMsmqBinding in WCF, so making a Powershell script seemed the quickest way! WCF does some strange formatting on the message that is sent through the wire, you can though see that our two alternatives gives also a bit different formatting, the first alternative being the most clean and with shortest syntax.

As the reader can see, the contents of the MSMQ queue that the NetMsmqBinding uses shows unreadable characters. That is because the MSMQ message item are containing actually WCF Messages. QueueExplorer showed me this fact, so next article will present a more lengthy version where the content can be properly decoded using Powershell to the rescue!

Basic WCF solution in Monodevelop

Basic WCF Solution in Monodevelop

I created a basic solution with a WCF Servicehost and client in Monodevelop today using MX Linux 17 "Horizon". To check it out, clone the following repository:
git clone https://bitbucket.org/toreaurstad/hellowcfmono
The source code is small and can be seen in a browser here: HelloWcfMono source code
If you have not installed Monodevelop in Linux yet, it is available as package "Monodevelop", "Monodevel" or "Monodevelop-complete", for example in MX-Linux I used:
apt-get install monodevel

The HelloWcf solution consists of three projects. The Service project is a console project, running the ServiceHost through the console. You will want to tweak Monodevelop to use External Console by right clicking and selecting Options=>Run=>General: "Run on external console". I just installed xterm to use the console as it is (apt get install xterm). In case Monodevelop crashes when you open the .sln file, another problem with Monodevelop, you can run the following command to open the .sln file directly in the root folder of the cloned repository.: monodevelop HelloWcf.sln
To run the WCF sample, right click on the Host project and choose Set as Startup project Choose first to Rebuild all (Ctrl+F8) to build the Service, Host and Client projects. Now press F5 to debug the Host project. The terminal window should show up, indicating that the WCF Service is running:

Now, switch over to a new terminal window and navigate to the Client project. Go to the bin folder, then the Debug folder. If you did not build Client, there are no files here, so do this now by right clicking on the Client project in Monodevelop and choose build. Now a file called Client.exe should pop up in your console. To run the client, enter: mono Client.exe Then you provide the Service a string through a call WCF service call with the proxy (Client) and get a reply. This project is really the basic set up of a client to get started coding WCF Servicehost and a proxy supporting BasicHttpBinding in .NET System.ServiceModel (which Mono actually supports). Developers can now use Linux and Monodevelop for example and commit code, while other developers use other platforms. The same .sln file can be openened in Visual Studio in Windows for example, while front-end guys use Apple to do their bit. Monodevelop is truly a possible bridge and will you will save money on license costs and freedom to add a lot of free software to use to build your projects. So what are you waiting for, grab hold of Monodevelop today and Linux and try it out! Nice thing to see that Mono framework supports WCF, much can be developed for .NET in Linux!

Call a Javascript function from Blazor page

This article will show how a Js function can be called from a Blazor page. First off, create a button like this:

 <button class="btn btn-warning" onclick="@SayHelloToBlazor">Click me!</button>

Then define the .Net method to handle the onclick event.

@using Microsoft.AspNetCore.Blazor.Browser.Interop

 private async void ShowAlert()
 {
    if (RegisteredFunction.Invoke("showAlert", "Hello World!"))
        Console.WriteLine("The Js function showAlert was called!");
 }

The code invokes a registered function with the invoke method and passing in the method name and an argument. Note that you must add the Interop namespace to Blazor in AspNetCore. We then add the Js function, but Blazor will give you a compiler error if you put the Js function in the same file as the Blazor page. Instead, add it in the index.html file under wwwroot folder of your Blazor project (check the wwwroot folder). You can define the Js function in a .js file or right into the index.html file.

    Blazor.registerFunction('showAlert', (msg) => {
        console.log(msg);
        alert(msg);
        return true;

    });

Note that if you refactor the Js method, your reference in the .DotNet code of Blazor will of course go stale, and you must update it. Since we return true (as Blazor wants you to do), we can act upon that in the Blazor code as a callback (check the async modifier of the DotNet method). That is what you need to do to get started with calling Javascript from Blazor page running in DotNetCore 2.1 and later.