Determine size of page via HttpModule

Here's an easy one for you:

I'm currently logging request duration via an HttpModule and I'd like to find out the number of bytes each page is as well.

HttpContext.Current.Response.OutputStream.Length throws a NotSupportedException.

What's an easy way to do this?

From stackoverflow Ben Scheirman

• I have an HttpModule that implements a stream rewriter. It derives from the Stream class. In my HttpModule I have the following code:

  void app_PreRequestHandlerExecute(object sender, EventArgs e)
  {
      HttpResponse response = HttpContext.Current.Response;
      response.Filter = new MyRewriterStream(response.Filter);
  }
  

  In the stream class I have the following code that overrides the default Write method:

  public override void Write(byte[] buffer, int offset, int count)
  {
       string outStr;
       outStr = UTF8Encoding.UTF8.GetString(buffer, offset, count);
       //Do useful stuff and write back to the stream
  }
  

  You can just take the length of the string at the second point

  Ben Scheirman : Do yo mean: response.Filter = new MyRewriterStream(response.OutputStream) ??

  Ben Scheirman : nevermind, you were right... it just looked like a typo. That did it!

  David : Be careful about converting the byte[] buffer to a string if the request is for a binary file.
  From Jason Z