Rack::Request - how do I get all headers?

Question

The title is pretty self-explanatory. Is there any way to get the headers (except for Rack::Request.env[])?

Answer 1

The HTTP headers are available in the Rack environment passed to your app:

HTTP_ Variables: Variables corresponding to the client-supplied HTTP request headers (i.e., variables whose names begin with HTTP_). The presence or absence of these variables should correspond with the presence or absence of the appropriate HTTP header in the request.

So the HTTP headers are prefixed with "HTTP_" and added to the hash.

Here's a little program that extracts and displays them:

require 'rack'  app = Proc.new do |env|   headers = env.select {|k,v| k.start_with? 'HTTP_'}     .collect {|key, val| [key.sub(/^HTTP_/, ''), val]}     .collect {|key, val| "#{key}: #{val}<br>"}     .sort   [200, {'Content-Type' => 'text/html'}, headers] end  Rack::Server.start :app => app, :Port => 8080 

When I run this, in addition to the HTTP headers as shown by Chrome or Firefox, there is a "VERSION: HTPP/1.1" (i.e. an entry with key "HTTP_VERSION" and value "HTTP/1.1" is being added to the env hash).

Answer 2

Based on @matt's answer, but this really gives you the request headers in a hash as requested in the question:

headers = Hash[*env.select {|k,v| k.start_with? 'HTTP_'}   .collect {|k,v| [k.sub(/^HTTP_/, ''), v]}   .collect {|k,v| [k.split('_').collect(&:capitalize).join('-'), v]}   .sort   .flatten] 

Depending on what key convention you prefer you might want to use something else instead of :capitalize.