How can the Accept-Encoding header be changed in IE with Url Monikers or other method?

Question

I'm developing a browser plugin and server component system that streams content with a custom encoding type. Now I would like to be able to detect on the server side whether the client can handle the special encoding, and would like to keep it consistent with the usual way things work with HTTP, so from the browser plugin I would like to add a new encoding in the Accept-Encoding request header. i.e.:

Accept-Encoding: gzip, deflate, myencoding

I have tried implementing IHttpNegotiate and setting it as an additional header in BeginningTransaction, but it seems to either ignore it or it gets overwritten later.

Answer 1

Please don't try to do this. Any approach that would allow you to modify the Accept-Encoding header (e.g. Asynchronous Pluggable Protocol wrapping) would necessarily be a hack, and will not work reliably because WinINET, proxies, etc, all make assumptions about the Accept-Encoding and Content-Encoding headers, and introducing a new scheme will not be reliable.

For instance, I've heard that one of the popular proxies will treat unknown encodings as GZIP and rewrite the Content-Encoding header in response; obviously that will break your scheme.