Modifying a HttpModule Request.Filter

[mpdoreilly]

Hi,

I've a webservice that has several typical webmethods that clients
call and get responses from.

(Side note: The websriivce is actually to implement the server side of
tr-069, the protocol is somewhat funny in that the server can send
arbitrary requests to the client in the RESPONSES to calls to its
webmethods)

When a client has finished calling methods and processing responses to
those requests it notifies the server that the server can start
sending arbitrary requests in its method Responses. The client
notifies the server of this situation by posting an EMPTY request to
the web service's .asmx

ie:

POST /Webservices/ACS/Service.asmx HTTP/1.1
Host: 10.1.83.36:80
User-Agent: GS_TR69_CPE-0.2
Connection: keep-alive
Cookie: ASP.NET_Session Id=pngyu45521cu ww45vb4px0ax
Content-Type: text/xml
Content-Length: 0

What I need to do is find some way to have this post call a predefined
"EmptyReque st" webmethod in the service (this will also get session
info into context free of charge).

SoapExtensions wont work because there isn't enough information in the
post to allow an appropriate webmethod to be selected.

Currently I have a HttpModule that hooks BeginRequest and adds a
filter to the HttpContext.Cur rent.Request.Fi lter.

The intention is to have the filter return a canned piece of well
formed SOAP/XML that causes the predefined EmptyRequest method to
fire.

All this (almost) works: Provided the Content-Length is >= 1 the
filter is Read from and it can return the appropriate XML and alter
the size correctly. So I can make it that any incoming request is
hijacked and causes the EmptyRequest method to fire.

However, when the HttpContext.Cur rent.Request.Co ntentLength = 0 the
filter is _never_ read from .. so the approach fails.

Any ideas how the ContentLength = 0 can be fixed or another .net
approach that would neatly resolve this? (Preferably, I'd like to stay
away from Isapi filters)

Regards,

Mike.