Modifying HTTP request and responses with a Browser Helper Object

Question

I want to modify HTTP requests headers using an Internet Explorer Browser Helper Object. I basically need to change a few headers for every request, and then modify the response before it returns to the browser.

I tried using the OnNavigate2 events, but those don't even give you access to all of the headers.

I tried making an Asynchronous Pluggable Protocol, but then I don't really have access to the default HTTP implementation, and i can't override the default HTTP requests.

Do you have any idea how this is supposed to be done? I prefer C#, but could use C++ if necessary.

Answer 1

The easiest way to do it is to use an http proxy to intercept everything the way Fiddler does.

See this description of the Fiddler PowerToy (Part 1).

Answer 2

It seems that you can only modify CUSTOM headers by using the headers parameters of the BeforeNavigate2 event. Not all the headers are accessible. This is a way to try to minimize the potential of the BHOs to act as a Trojans. Use a HTTP proxy instead.

Answer 3

It can be done with URL monikers. There is an implementation of something like that by a guy called Igor Tandetik. You can find links to the code in: microsoft.public.inetsdk.programming google group - just look for PassthruAPP. (I would have posted a link but apparently new users are not allowed to do this)

It doesn't directly support modifying the response body though. You will have to insert a hook into the IInternetProtocolImpl::Read method.