Click here to Skip to main content
Click here to Skip to main content

HTTP compression in .NET Framework 2.0

, 1 May 2007
Rate this:
Please Sign up or sign in to vote.
An article on how to request and handle HTTP compression in .NET Framework 2.0.

Introduction

This article describes the implementation of a utility class that will allow HTTP requests informing the server (or any appliance in the network between the client and the server) what types of compression it can handle and uncompress the response from the server (if any) without changing the client application.

HTTP compression is very useful when the cost of the connection is high.

The factory pattern of creating WebRequest instances

The WebRequest supplies two methods to create instances:

The WebRequest class uses instances of classes that implement the IWebRequestCreate interface and are registered in the webRequestModules section in the configuration files. The Create method (called by both CreateDefault and Create) returns an initialized instance of a WebRequest descendent class capable of performing a standard request/response transaction for the protocol without needing any protocol-specific fields modified.

On the other hand, the previously created WebRequest derived instances will return WebResponse derived instances that will handle the HTTP response.

Because of the way the factory pattern is implemented, we can change the behavior of already built applications (our applications or even the .NET Framework) to request and handle HTTP compression, changing only the configuration files.

Since in versions 2.0 and above of the .NET framework already support compression, there is no need to supply WebRequestand WebResponse derived class implementations. All that's needed is a class that implements the IWebRequestCreate interface to create the WebRequestderived instance and set it up.

The code

As shown before, to add HTTP compression to our applications, we just have to build three classes:

CompressibleHttpRequestCreator

In order for the applications that use HttpWebRequest and HttpWebResponse to work without any changes, CompressibleHttpRequestCreator.Create has to return a HttpWebRequest instance. Unfortunately, there is no public construtor for HttpWebRequest or publicly accessible implementation of IWebRequestCreate.Create that creates a HttpWebRequest instance, so some reflection will be needed.

The implementation of IWebRequestCreate.Create just creates an instance of HttpWebRequest and sets its HttpWebRequest.AutomaticDecompression to accept all types of compression.

public class CompressibleHttpRequestCreator : IWebRequestCreate
{
    public CompressibleHttpRequestCreator()
    {
    }

    WebRequest IWebRequestCreate.Create(Uri uri)
    {
        HttpWebRequest httpWebRequest = 
            Activator.CreateInstance(typeof(HttpWebRequest),
            BindingFlags.CreateInstance | BindingFlags.Public | 
            BindingFlags.NonPublic | BindingFlags.Instance,
            null, new object[] { uri, null }, null) as HttpWebRequest;

        if (httpWebRequest == null)
        {
            return null;
        }

        httpWebRequest.AutomaticDecompression =DecompressionMethods.GZip | 
            DecompressionMethods.Deflate;

        return httpWebRequest;
    }
}  

Configuration

Now, to add HTTP compression support to any application, all that's needed is to add the corresponding entries to the webRequestModules section in the configuration file.

<configuration>
  <system.net>
    <webRequestModules>
      <remove prefix="http:"/>
      <add prefix="http:" 
            type="Pajocomo.Net.CompressibleHttpRequestCreator, Pajocomo" />
    </webRequestModules>
  </system.net>
</configuration>

History

When I first ported this from .NET 1.1, I completely missed the fact that HttpWebRequest and HttpWebResponse already implemented compression.

Thanks to Björn to point that out to me.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

Share

About the Author

Paulo Morgado
Software Developer (Senior) Paulo Morgado
Portugal Portugal

Comments and Discussions

 
GeneralWarnings Pinmembernzeemin6-Mar-07 20:51 
GeneralRe: Warnings PinmemberPaulo Morgado6-Mar-07 23:54 
GeneralCompression engine that WORKS for me! Pinmemberpelam1-Mar-07 13:26 
GeneralRe: Compression engine that WORKS for me! PinmemberPaulo Morgado1-Mar-07 13:51 
QuestionContentEncoding Pinmembercaptainq24-Oct-06 16:31 
AnswerRe: ContentEncoding PinmemberPaulo Morgado24-Oct-06 23:19 
GeneralRe: ContentEncoding Pinmembercaptainq5-Nov-06 3:55 
GeneralRe: ContentEncoding PinmemberPaulo Morgado5-Nov-06 5:36 
Have you checked with Fiddler if the rigth HTTP headers are being sent?
 
You should be aware that this is a server side compression only protocol and, ASMX being a dynanlic content needs compression explicitly enabled on IIS6.
 
If you need to send compressed data to your web server, you need to code your web service to handle that (or your WCF binding).
 
There are also issues with this on .NET 1.1. I wonder if they affect .NET 2.0.
 
Paulo Morgado
Portugal - Europe's West Coast

GeneralRe: ContentEncoding Pinmembercaptainq5-Nov-06 9:50 
GeneralSystem.Runtime.Serialization.dll PinmemberJntn14-May-06 8:53 
GeneralRe: System.Runtime.Serialization.dll PinmemberPaulo Morgado14-May-06 11:31 
GeneralRe: System.Runtime.Serialization.dll PinmemberJntn14-May-06 23:22 
GeneralRe: System.Runtime.Serialization.dll PinmemberPaulo Morgado15-May-06 0:39 
Generalweb service specific exception PinmemberPetr Melichar22-Apr-06 3:03 
GeneralRe: web service specific exception PinmemberPaulo Morgado14-May-06 11:20 
AnswerRe: web service specific exception Pinmemberrealmaestro3-Apr-07 16:48 
GeneralRe: web service specific exception PinmemberPaulo Morgado3-Apr-07 22:59 
QuestionImport problem PinmemberTommyB811-Mar-06 5:09 
AnswerRe: Import problem PinmemberPaulo Morgado12-Mar-06 2:07 
GeneralRe: Import problem PinmemberTommyB812-Mar-06 2:24 
GeneralRe: Import problem PinmemberPaulo Morgado12-Mar-06 3:01 
GeneralRe: Import problem PinmemberTommyB812-Mar-06 3:30 
GeneralRe: Import problem PinmemberPaulo Morgado12-Mar-06 7:37 
AnswerRe: Import problem PinmemberTommyB812-Mar-06 7:44 
QuestionHelp - How to do? PinmemberRSArockiam6-Feb-06 21:44 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web04 | 2.8.141223.1 | Last Updated 1 May 2007
Article Copyright 2006 by Paulo Morgado
Everything else Copyright © CodeProject, 1999-2014
Layout: fixed | fluid