Created by: diegonc
Since version 1.0.0, Node has added support for getting the raw headers from an incomming message, like the ones http.request passes to its callback.
This opens the possibility of sending the headers to the client using the same capitalization as the target server used when responding to our request.
What the PR proposes to accomplish this goal is to add a new option, keepHeaderCase, that instructs the writeHeaders outgoing pass to build a map of lower-cased headers to its original representation located in the rawHeaders property of proxyRes.
To keep backwards compatibility with earlier versions of Node, the outgoing pass above uses the keys of the proxyRes.headers map as the first parameter of res.setHeader.
There are some corner cases regarding headers set by preceding passes; it wasn't clear to me what to do with those. But otherwise, the simple test added by the first commit in this PR works ok.
What do you think about this feature?
Thanks, Diego