Return data not compressing regardless of applicationhost.config

Question

I am having issues with compressing data returned from my ASP.NET application. I'll have a test method GetUserInfo that will return data. To test, I only have the following in this method to have a big enough result set:

UserModel users = new List<UserModel>();

for (int i = 0; i < 2000; i++)
{
    UserModel _usr = new UserModel();
    _usr = new UserModel();
    _usr.Id = i.ToString();
    _usr.Number = "Abc" + i;
    _usr.Name = i + "Abc";
    users.Add(_usr);
    _user = null;
}

HttpResponseMessage json = Request.CreateResponse(HttpStatusCode.OK, users);

return json;

In applicationhost.config (in IISExpress folder), I have the following:

<section name="httpCompression" overrideModeDefault="Allow" />

And in this same file, <httpCompression...> contains:

    <httpCompression directory="%TEMP%\iisexpress\IIS Temporary Compressed Files">
        <scheme name="gzip" dll="C:\Windows\System32\inetsrv\gzip.dll" />
        <dynamicTypes>
            <add mimeType="*/*" enabled="true"/>
            <add mimeType="text/*" enabled="true"/>
            <add mimeType="message/*" enabled="true"/>
            <add mimeType="application/javascript" enabled="true"/>
            <add mimeType="application/json" enabled="true"/>
            <add mimeType="application/json; charset=utf-8" enabled="true" />
            <add mimeType="application/xml; charset=utf-8" enabled="true" />
            <add mimeType="*/*" enabled="false"/>
        </dynamicTypes>
        <staticTypes>
          <add mimeType="*/*" enabled="true"/>
          <add mimeType="text/*" enabled="true"/>
          <add mimeType="message/*" enabled="true"/>
          <add mimeType="application/javascript" enabled="true"/>
          <add mimeType="application/json" enabled="true"/>
          <add mimeType="application/json; charset=utf-8" enabled="true" />
          <add mimeType="application/xml; charset=utf-8" enabled="true" />
          <add mimeType="*/*" enabled="false"/>
        </staticTypes>
    </httpCompression>

Below is what I see from PostMan regarding Content in the return headers:

Content-Length →3991

Content-Type →application/json; charset=utf-8

But I'm not seeing Content-Type. I hope I included enough details here.

Answer 1

So I edited the hostApplication.config file located in: c:\\windows\\system32\\inetsrv\\config. I think I was looking at the wrong one in SysWOW64. But I added the following, and it worked.

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