A case of a deadlock in a .NET application


I recently had an interesting issue in one of our applications. The SMS router, responsible for sending and receiving SMSes, hanged – there was no CPU usage and we haven’t observed any activity in the application logs. I collected a full memory dump and restarted the service, which seemed to come back to its normal state. Curious what happened I opened the dump in WinDbg, loaded PDE and SOS and started an investigation

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A case of a deadlock in a .NET application

Timeouts when making web requests in .NET


In one of our applications I recently observed timeouts in code performing HTTP requests to the REST service. While investigating this issue I discovered few interesting facts about System.Net namespace and would like to share them with you. We were using objects of type System.Net.HttpWebRequest in our code, but some of the information presented in this post will also apply to the newer System.Net.HttpClient implementation.

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Timeouts when making web requests in .NET

How to debug Windows Services written in .NET? (part I)


Diagnosing Windows Services might sometimes be cumbersome – especially when errors occur during the service start. In this two-parts series I am going to show you different ways how to handle such problems in production. In the first part we will focus on “exceptions discovery” techniques which very often are enough to figure out why our service is not working. In the second part we will setup a debugging environment and attach a debugger to our service. Let’s start then.

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How to debug Windows Services written in .NET? (part I)

Common authentication/authorization between .NET4.0 and .NET4.5 web applications


ASP.NET Identity is a big step forward and we should profit from its features, such as: two-step authentication, support for OpenId providers, stronger password hashing and claims usage. One of its requirements is .NET4.5 which might be a blocker if you have in your farm legacy Windows 2003 R2 servers still hosting some of your MVC4 (.NET4.0) applications. In this post I would like to show you how you may implement common authentication and authorization mechanisms between them and your new ASP.NET MVC5 (and .NET4.5) applications deployed on newer servers. I assume that your apps have a common domain and thus are able to share cookies.

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Common authentication/authorization between .NET4.0 and .NET4.5 web applications

Collect .NET applications traces with sysinternals tools


In this short post I would like to show you how, with sysinternals tools, you may noninvasively trace .NET applications. This is especially useful in production environment where you can’t install your favorite debugger and hang whole IIS to diagnose an issue. We will work with three tools: dbgview, procdump and procmon. Let’s start with the first one.

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Collect .NET applications traces with sysinternals tools

ASP.NET Anti-Forgery Tokens internals


Anti-Forgery Tokens were introduced in ASP.NET in order to prevent Cross-Site Request Forgeries. There are many sites which describe how to use and configure those tokens in your application. But in this post I’m going to show you what exactly those tokens contain, where they are generated and how to customize them.

Let’s start our journey from a sample Razor HTTP form:

...
@using (Html.BeginForm()) {
    @Html.AntiForgeryToken()
    @Html.TextBoxFor(m => m.Name)<br />
    @Html.TextBoxFor(m => m.FullName)<br />
    <br />
    <input type="submit" value="Test" />
}
...

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ASP.NET Anti-Forgery Tokens internals

Reference Source, dotPeek and source code debugging


Not so long ago Microsoft has made .NET source code browsable through a really nice page: http://referencesource.microsoft.com/. Additionally, they promised that the .NET Framework source code debugging will finally work in Visual Studio. At almost the same time JetBrains published EAP of its dotPeek tool with some great features that make “reverse-engineered debugging” extremely easy. And for other DLLs we still have the old Microsoft Public Symbols server. In this post I am going to show you how I configure my system and Visual Studio for different debugging scenarios.

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Reference Source, dotPeek and source code debugging