IHttpModule Filter Html Sharepoint

[Q1Q]

Hi,

I'm rather new to both ASP.net and Sharepoint and I need to do some filtering of the response output from a Sharepoint application.

I've read about the possibility to intercept the response in ASP.net applications "just before" it is sent to the client. It succeeded to do that for asp-pages served by Sharepoint, but my problem is that I want to intercept the pure HTML files only.

I do catch the response but I'm not able to get the call to the overridden write() in my filter. It only works for the asp-pages.

See the code below. Could somebody please have a look and try to help me out =)

public class MOSSCleanupModule : IHttpModule
{
   public void Init(HttpApplication app)
   {
      app.ReleaseRequestState += new EventHandler(InstallResponseFilter);
   }

  private void InstallResponseFilter(object sender, EventArgs e)
  {
     HttpResponse response = HttpContext.Current.Response;
     HttpRequest request = HttpContext.Current.Request;
     if (response.ContentType == "text/html" && request.Url.AbsolutePath.EndsWith(".htm"))
     {
        Debug.Write("in InstallResponseFilter()");
        response.Filter = new ModifyHtmlContentFilter(response.Filter);
     }
  }

  public void Dispose()
  {}
}

public class ModifyHtmlContentFilter : Stream
{
   private Stream responseStream;

   public ModifyHtmlContentFilter(Stream inputStream)>
   {
      Debug.Write("in ModifyHtmlContentFilter");
      this.responseStream = inputStream;
   }

   public override void Write(byte[] buffer, int offset, int count)
   {
      Debug.Write("in custom Write()");
      StringBuilder html = new StringBuilder(System.Text.UTF8Encoding.UTF8.GetString(buffer, offset, count));
      this.modifyHtml(html, "..");
      byte[] data = System.Text.UTF8Encoding.UTF8.GetBytes(html.ToString());
      responseStream.Write(data, 0, data.Length);
    }

   private void modifyHtml(StringBuilder html, string search)
   {
      Debug.Write("in modifyHtml()");
      // Modify the html
   }

#region Filter overrides

public override bool CanRead{get{return true;}

public override bool CanSeek{get{return true;}}

public override bool CanWrite{get{return true;}}

public override void Close(){responseStream.Close();}

public override void Flush(){responseStream.Flush();}

public override long Length{get{return 0;}}

public override long Position{get{return position;}set{position = value;}}

public override long Seek(long offset, SeekOrigin origin){return responseStream.Seek(offset, origin);}

public override void SetLength(long length){responseStream.SetLength(length);}

public override int Read(byte[] buffer, int offset, int count){return responseStream.Read(buffer, offset, count);}

#endregion

}
}

[Q1Q]

It started working for pure html file when I changed the EventHandler to BeginRequest to catch it earlier in the pipeline.

[Hack]

It started working for pure html file when I changed the EventHandler to BeginRequest to catch it earlier in the pipeline.

And did this resolve your problem?

[Q1Q]

Yes it did.

Unfortunately I know too little about the Http pipeline in ASP.net to know exactly why it solved the problem.

[Hack]

A couple of things that may help in understanding the pipeline

http://blog.crowe.co.nz/archive/2007/04/08/700.aspx

http://msdn.microsoft.com/en-us/magazine/cc188942.aspx

http://aspnet.4guysfromrolla.com/articles/011404-1.aspx