Allow extra HTTP headers in BOSH and WebSockets.

[varnerac]

This is a WIP PR

Proposed changes include:

• Allowing extra headers for BOSH and WebSockets

This isn't ready yet. I just wanted to test the waters and see if you had an appetite for a patch like this. We want the ability to add CORS headers and security headers like HSTS to the BOSH and WebSockets endpoints.

[michalwski]

Hi @varnerac, thanks for the patch. There are appetite and need for the CORS headers, there is even another PR #1195 where the headers are always added in case of BOSH connection. I think making them configurable would be a more flexible solution.

When it comes to your changes, they don't integrate well with cowboy yet. All the tests connecting users over BOSH or WS failed. You can try it locally by running the following commands:

tools/test-runner.sh --skip-small-tests --skip-cover --preset internal_mnesia -- ws

or

tools/test-runner.sh --skip-small-tests --skip-cover --preset internal_mnesia -- bosh

More on the test-runner.sh the script you can find in the help provided by the tool and https://mongooseim.readthedocs.io/en/latest/developers-guide/Testing-MongooseIM/

[varnerac]

I'll tackle this in another PR