How to enable IIS compression for WCF services?

Question

I currently use a custom gzip encoder for my WCF service. I want to replace it with the built-in IIS 7 compression if that is possible. I can't find info online on how to that.

Is there any way to enable IIS 7 compression for WCF services? Do you know if this will be supported out-of-the-box with .Net 4?

Edit June 15th: I'm still looking for a way to replace our custom gzip encoder with a mainstream approach so if you know how to do that with .Net 4 and IIS 7, please answer this question.

Thanks

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Sidebar : My attempt at doing this manually

Since I can't find how to do it by simply turning a few knobs I decided to try and enable it manually.

So far I have:

• Installed and enabled the IIS 7 Dynamic Compression Module
• Changed the section of the applicationHost.config file to enable compression for mimeType="application/soap+xml" and mimeType="application/xop+xml".

I used an HTTP sniffer to sniff traffic sent from my app (Windows Forms). I see that requests do not have the Accept-Encoding:gzip,deflate http header.

So I

• Added it manually to all outgoing calls using the OperationContextScope class and its OutgoingMessageProperties. (I will post the details later if I find the solution).

With the http sniffer, I can see that the client header now has the correct header:

POST /### path to my service ####/MyService.svc HTTP/1.1
MIME-Version: 1.0
Content-Type: multipart/related; type="application/xop+xml";
    start="<http://tempuri.org/0>";
    boundary="uuid:####### some uuid #############";
    start-info="application/soap+xml"
Accept-Encoding: gzip,deflate
Host: ####### my server name #############
Content-Length: 1753
Expect: 100-continue

But the server response is still not compressed.

Why is the server response not compressed? Have I used the correct mime types? Once I get the server to return a compressed answer, will the client automatically decompress it or will have to write code on the client side to decompress?

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Thanks for your help

Answer 1

I had the same problem; .aspx pages were compressed but WCF content wasn't. It has to do with the content type returned by the WCF service, which got appended to the mime-type.

I got it to work with the following section in the ApplicationHost.config:

<dynamicTypes>
    <add mimeType="text/*" enabled="true" />
    <add mimeType="message/*" enabled="true" />
    <add mimeType="application/*" enabled="true" />
    <add mimeType="*/*" enabled="false" />
</dynamicTypes>

Here's what I did (most of the same steps as mentioned already):

• Install the Dynamic Compression Role Service for IIS role
• Enable Dynamic Content Compression for the website that you use to host the WCF service
• Open %SystemRoot%\system32\inetsrv\config\applicationhost.config and add the relevant content type to the section of the
• After this it still didn't work.
• I checked the data with Firefox' Tamper Data and noticed the content type returned was actually "application/xml; charset=utf-8".
• After adding the complete content type, including the "; charset=utf-8" to the section, it worked:

<add mimeType="application/xml; charset=utf-8" enabled="true" />

As I felt that the character set encoding should not be determining if the compression works or not, I ended up letting IIS compress all application/* content types.

Answer 2

This is useful for IIS 6

http://ramon.bloggingabout.net/2008/11/06/wcf-and-http-gzipdeflate-compression-and-silverlight/

(updated URL)