Question

I am currently developing an API where size matters: I want the answer to contain as few bytes as possible. I optimized my JSON answer, but rails still responds with many strange headers

HTTP/1.1 200 OK
Server: nginx/0.7.67                            # Not from Rails, so ok.
Date: Wed, 25 Apr 2012 20:17:21 GMT             # Date does not matter. We use ETag Can I remove this?
ETag: "678ff0c6074b9456832a710a3cab8e22"        # Needed.
Content-Type: application/json; charset=utf-8   # Also needed.
Transfer-Encoding: chunked                      # The alternative would be Content-Length, so ok.
Connection: keep-alive                          # Good, less TCP overhead.
Status: 200 OK                                  # Redundant! How can I remove this?
X-UA-Compatible: IE=Edge,chrome=1               # Completely unneded.
Cache-Control: no-cache                         # Not needed.
X-Request-Id: c468ce87bb6969541c74f6ea761bce27  # Not a real header at all.
X-Runtime: 0.001376                             # Same goes for this
X-Rack-Cache: invalidate, pass                  # And this.

So there are lots of unnecessary HTTP headers. I could filter them in my server (nginx), but is there a way stop this directly in rails?

Answer 1

You can do this with a piece of Rack middleware. See https://gist.github.com/02c1cc8ce504033d61bf for an example of to do it in one.

When adding it to your app config, use something like config.middleware.insert_before(ActionDispatch::Static, ::HeaderDelete)

You want to insert it before whatever the first item in the list that displays when you run rake middleware, which in my case is ActionDispatch::Static.

http://guides.rubyonrails.org/rails_on_rack.html may be somewhat helpful if you haven’t been exposed to Rack in the Rails context before.