Controlling cache expiration of Service.svc/js

Question

Hello,

Environment VS 2008, .NET 3.5, Windows 2003 Server

I'm calling WCF Service decorated with
<OperationContract()> _
<WebGet(RequestFormat:=WebMessageFormat.Xml)> _

from web page script manager.
<asp:ScriptManager ID="SM" runat="server" >
<Services>                    <asp:ServiceReference Path="~/
Service.svc" />         </Services>     </asp:ScriptManager>

The Service proxy file http://MYSERVER/AJAXWCF/Service.svc/js is
generated with caching header of expire immediately
HTTP/1.0 Expires Header is present: Tue, 10 Mar 2009 22:17:49 GMT

The web.config have debug=false

I don't want to embed the script into my page, I want it in separate
cached JS file with one year expiration same as scriptresource.axd JS
files or better with configurable cache expiration. Is there any way
to control cache expiration of Service.svc/js

Regards

Answer 1

The "Expires" and "Last-Modified" headers are hardcoded by WCF, if your service is hosted inside IIS, you could try writing a custom IHttpModule to modify the HTTP response as follows:

public sealed class JavascriptCacheabilityModule : IHttpModule
{
    private HttpApplication app;
    public void Init(HttpApplication context)
    {
        app = context;
        app.EndRequest += new EventHandler(EndRequest);
    }

    private void EndRequest(object sender, EventArgs e)
    {
        var path = app.Context.Request.Path.ToLower().Replace('\\', '/');
        if (path.EndsWith(".svc/js"))
        {
            var lastModified = DateTime.UtcNow;
            var expires = lastModified + TimeSpan.FromDays(365);

            app.Context.Response.Cache.SetLastModified(lastModified);
            app.Context.Response.Cache.SetExpires(expires);
            app.Context.Response.Cache.SetCacheability(HttpCacheability.Public);
        }
    }

    public void Dispose()
    {
        app.BeginRequest -= EndRequest;
        app = null;
    }
}

You need to configure the HTTP module as follows:
<system.web>
  <httpModules>
    <add name="JavascriptCacheabilityModule" type="RestService.JavascriptCacheabilityModule, RestService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"/>
  </httpModules>
</system.web>

<system.webServer>
  <modules>
    <add name="JavascriptCacheabilityModule" type="RestService.JavascriptCacheabilityModule, RestService, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"/>
  </modules>
</system.webServer>

Hope this helps

---

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Answer 2

Thank you. just verified that it really work for WCF ScriptService
Unfortunately it doesn't work for asmx scriptservice

The asmx script service always override expires header to one year ago as described in following post.
http://forums.asp.net/p/1423422/3164625.aspx

Any idea how to make it work with ASMX beside migrating to WCF?

Answer 3

Try the  below property also with the header

context.Response.Cache.SetMaxAge(

TimeSpan.FromDays(5));