Enabling gzip compression on Azure App Service

Question

I have a web app hosted in microsoft azure. As local IIS uses compression for both static and dynamic content I expected this to work on azure platform as well. As it seems compression does not work as json and css files for example are returned uncompressed:

I have tried to set compression as mentioned in serveral posts (e.g. gzip compression in Windows Azure Websites or ) like this without any changes to the result:

<system.webServer>
    <urlCompression doStaticCompression="true" doDynamicCompression="true" />
  <httpCompression>
    <dynamicTypes>
    <clear />
    <add enabled="true" mimeType="text/*"/>
    <add enabled="true" mimeType="message/*"/>
    <add enabled="true" mimeType="application/x-javascript"/>
    <add enabled="true" mimeType="application/javascript"/>
    <add enabled="true" mimeType="application/json"/>
    <add enabled="false" mimeType="*/*"/>
    <add enabled="true" mimeType="application/atom+xml"/>
    <add enabled="true" mimeType="application/atom+xml;charset=utf-8"/>
  </dynamicTypes>
  <staticTypes>
    <clear />
    <add enabled="true" mimeType="text/*"/>
    <add enabled="true" mimeType="message/*"/>
    <add enabled="true" mimeType="application/javascript"/>
    <add enabled="true" mimeType="application/atom+xml"/>
    <add enabled="true" mimeType="application/xaml+xml"/>
    <add enabled="true" mimeType="application/json"/>
    <add enabled="false" mimeType="*/*"/>
  </staticTypes>
 </httpCompression>
[...]
</system.webServer>

As it seems the azure portal does not give me any option to change compression.

What do I need to do to enable compression or is it only possible when using a Vserver in azure?

Solution

You can change this in the web.config:

<system.webServer>
  <urlCompression doStaticCompression="true" doDynamicCompression="true" />
</system.webServer>

Then:

<httpCompression>
  <dynamicTypes>
    <clear />
    <add enabled="true"  mimeType="text/*"/>
    <add enabled="true"  mimeType="message/*"/>
    <add enabled="true"  mimeType="application/x-javascript"/>
    <add enabled="true"  mimeType="application/javascript"/>
    <add enabled="true"  mimeType="application/json"/>
    <add enabled="false" mimeType="*/*"/>
    <add enabled="true"  mimeType="application/atom+xml"/>
    <add enabled="true"  mimeType="application/atom+xml;charset=utf-8"/>
  </dynamicTypes>
  <staticTypes>
     <clear />
     <add enabled="true" mimeType="text/*"/>
     <add enabled="true" mimeType="message/*"/>
     <add enabled="true" mimeType="application/javascript"/>
     <add enabled="true" mimeType="application/atom+xml"/>
     <add enabled="true" mimeType="application/xaml+xml"/>
     <add enabled="true" mimeType="application/json"/>
     <add enabled="false" mimeType="*/*"/>
   </staticTypes>
 </httpCompression>

source: Microsoft forum

Comments

[edesr]

Hi Peter, I changed the web.config (updated my post) with the sample you provided. I checked the result and compression isn't working. Is it correct to add the httpCompression tag inside the system.webServer tag?

[Darren]

The above information is correct, however it doesn't work for me either, did you ever get it to work?

[Old fart]

I believe this above is for Websites only

[code-assassin]

I had the same issue on an Azure Web App using the same configuration like yours but it seemed not to work. I left it for some time refreshed the page at it worked. I guess it might have been some caching issue somewhere. Also I removed the application/json mime type from the statictypes section. I don't want the server serving me a cached version because most often they are results of controller actions fetched from a database. You can check this link for more information iis.net/configreference/system.webserver/httpcompression

[Pablo Jomer]

I have the same issue no solution in sight.

[Lyubomir Ivanov Valchev]

@code-assassin I am having the same issue with my website on Azure. Any additional advise other than what you already said?