IIS HttpCompression settings to compress only json responses (ajax)

Question

I have been playing with the "applicationHost.config" file in "C:\Windows\System32\inetsrv\config" directory, so far so good, I just want to make sure of something:

<httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files">
    <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" />
    <staticTypes>
            ......
    </staticTypes>
    <dynamicTypes>
            ......
            <add mimeType="application/json" enabled="true" /> 
            <add mimeType="*/*" enabled="false" />
    </dynamicTypes>

As you can see, I added the line <add mimeType="application/json" enabled="true" /> . Will this ensure only dynamic Ajax calls using jquery will be compressed? I am calling my ASP.NET Page Methods using:

$.ajax({
    type: "POST",
    url: 'someur.aspx/someMethod',
    contentType: "application/json; charset=utf-8",
    .....

Am I correct?

Answer 1

you need to add 2 content types to enable dynamic compression for JSON:

        <httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files">
            <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" />
            <dynamicTypes>
                <add mimeType="application/json" enabled="true" />
                <add mimeType="application/json; charset=utf-8" enabled="true" />       

                    <!-- all other MIME type come here -->

                <add mimeType="*/*" enabled="false" />
            </dynamicTypes>
        </httpCompression>