[Jetty-support] Possible architecture for header injection

[Callum H. <cal...@go...>]

I wish to provide users with a mechanism for injecting request headers
into requests emanating from their browsers.  I'm considering a
client-side solution like the Firefox plug-in Modify Headers.  However
I'd also like to establish if a server-side mechanism is possible.  As
a Java developer, Jetty stands out as a possible platform for a
solution.

There are two use cases.

1. User accesses a web app UI and uses it to modify headers to be used
for requests passing through a proxy

2. User makes requests which are directed through the proxy, which
adds the headers set in use case 1.

There is a further complication in that any solution must finally
submit requests to an existing proxy.  Here's a schematic of how the
situation is now, and how it might be in the future:

Now:

Browser ---------> Proxy A ----------> Destination

Future:

             use case 2
Browser -----------------> Proxy B/Header Modifier ---------> Proxy A
-----------> Destination
|                                        |
\----------------------------------------/
          use case 1

I apologise if the ascii art doesn't work out.

I was thinking that support for multiple users would be possible by
storing header setting in the session which could be established from
requests from both use cases.

Can anyone suggest if Jetty 5 or 6 has a place in this architecture,
and give some suggestions of how to approach a solution?

Many thanks,
Callum.