[apache] Set up an HTTP proxy to insert a header

I need to test some HTTP interaction with a client I'd rather not modify. What I need to test is the behavior of the server when the client's requests include a certain, static header.

I'm thinking the easiest way to run this test is to set up an HTTP proxy that inserts the header on every request. What would be the simplest way to set this up?

Use http://www.proxomitron.info and set up the header you want, etc.

Rather than using a proxy, I'm using the Firefox plugin "Modify Headers" to insert headers (in my case, to fake a login using the Single Sign On so I can test as different people).

If you have ruby on your system, how about a small Ruby Proxy using Sinatra (make sure to install the Sinatra Gem). This should be easier than setting up apache. The code can be found here.

i'd try tinyproxy. in fact, the vey best would be to embedd a scripting language there... sounds like a perfect job for Lua, especially after seeing how well it worked for mysqlproxy

You can also install Fiddler (http://www.fiddler2.com/fiddler2/) which is very easy to install (easier than Apache for example).

After launching it, it will register itself as system proxy. Then open the "Rules" menu, and choose "Customize Rules..." to open a JScript file which allow you to customize requests.

To add a custom header, just add a line in the OnBeforeRequest function:

oSession.oRequest.headers.Add("MyHeader", "MyValue");

I have had co-workers that have used Burp ("an interactive HTTP/S proxy server for attacking and testing web applications") for this. You also may be able to use Fiddler ("a HTTP Debugging Proxy").