GZip system.web.optimization bundles

Question

I am using the new System.Web.Optimization and have created a bundle like this:

bundles.Add(New ScriptBundle("~/bundles/BaseJS").Include(
                "~/Resources/Core/Javascripts/jquery-1.7.1.js",
                "~/Resources/Core/Javascripts/jquery-ui-1.8.16.js",
                "~/Resources/Core/Javascripts/jquery.validate.js",
                "~/Resources/Core/Javascripts/jquery.validate.unobtrusive.js",
                "~/Resources/Core/Javascripts/jquery.unobtrusive-ajax.js"))

and in my view I have added this

@System.Web.Optimization.Scripts.Render("~/bundles/BaseJS")

In fiddler the URL comes across with an expires header of 1 year in the future and a content type of text/javascript

In the web.config I have some code for gzip that is working on static JS files but it doesn't seem to on the minified bundles.

<staticContent>
  <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="365.00:00:00"/>
  <remove fileExtension=".js"/>
  <mimeMap fileExtension=".js" mimeType="text/javascript"/>
</staticContent>
<urlCompression doDynamicCompression="true" doStaticCompression="true" dynamicCompressionBeforeCache="true"/>
<httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files">
  <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll"/>
  <dynamicTypes>
    <add mimeType="text/*" enabled="true"/>
    <add mimeType="text/javascript" enabled="true"/>
  </dynamicTypes>
  <staticTypes>
    <add mimeType="text/*" enabled="true"/>
    <add mimeType="text/javascript" enabled="true"/>
  </staticTypes>
</httpCompression>

Is there a way to make the render bundle gzip the content?

Answer 1

With the latest ASP.NET Optimization (v1.1.2), the GZipTransform class does not work well.

I found a new way with a custom Bundle class that will always compress bundle content (that was transformed and cached) before response:

public class GZipBundle : Bundle
{
    public GZipBundle(string virtualPath, params IBundleTransform[] transforms)
        : base(virtualPath, null, transforms) { }

    public override BundleResponse CacheLookup(BundleContext context)
    {
        if (null != context) GZipEncodePage(context.HttpContext);
        return base.CacheLookup(context);
    }

    // Sets up the current page or handler to use GZip through a Response.Filter.
    public static void GZipEncodePage(HttpContextBase httpContext)
    {
        if (null != httpContext && null != httpContext.Request && null != httpContext.Response
            && (null == httpContext.Response.Filter
            || !(httpContext.Response.Filter is GZipStream || httpContext.Response.Filter is DeflateStream)))
        {
            // Is GZip supported?
            string acceptEncoding = httpContext.Request.Headers["Accept-Encoding"];
            if (null != acceptEncoding
                && acceptEncoding.IndexOf(DecompressionMethods.GZip.ToString(), StringComparison.OrdinalIgnoreCase) >= 0)
            {
                httpContext.Response.Filter = new GZipStream(httpContext.Response.Filter, CompressionMode.Compress);
                httpContext.Response.AddHeader("Content-Encoding", DecompressionMethods.GZip.ToString().ToLowerInvariant());
            }
            else if (null != acceptEncoding
                && acceptEncoding.IndexOf(DecompressionMethods.Deflate.ToString(), StringComparison.OrdinalIgnoreCase) >= 0)
            {
                httpContext.Response.Filter = new DeflateStream(httpContext.Response.Filter, CompressionMode.Compress);
                httpContext.Response.AddHeader("Content-Encoding", DecompressionMethods.Deflate.ToString().ToLowerInvariant());
            }

            // Allow proxy servers to cache encoded and unencoded versions separately
            httpContext.Response.AppendHeader("Vary", "Content-Encoding");
        }
    }
}

// Represents a bundle that does CSS minification and GZip compression.
public sealed class GZipStyleBundle : GZipBundle
{
    public GZipStyleBundle(string virtualPath, params IBundleTransform[] transforms) : base(virtualPath, transforms) { }
}

// Represents a bundle that does JS minification and GZip compression.
public sealed class GZipScriptBundle : GZipBundle
{
    public GZipScriptBundle(string virtualPath, params IBundleTransform[] transforms)
        : base(virtualPath, transforms)
    {
        base.ConcatenationToken = ";" + Environment.NewLine;
    }
}

Then you can use GZipStyleBundle and GZipScriptBundle to replace the original Bundle classes: StyleBundle, ScriptBundle. Ex:

public static class BundleConfig
{
    // For more information on Bundling, visit http://go.microsoft.com/fwlink/?LinkId=254725
    public static void RegisterBundles(BundleCollection bundles)
    {
        bundles.Add(new GZipScriptBundle("~/bundles/jquery.js").Include(...));
        bundles.Add(new GZipScriptBundle("~/bundles/jquery-ui.js", new JsMinify()).Include(...));

        bundles.Add(new GZipStyleBundle("~/bundles/all.css", new CssMinify()).Include(...));
    }
}

Regards