gistfile1.rbx

module Middleware
  class ETag < ::Merb::Rack::Middleware
    def call(env)
      status, headers, body = @app.call(env)

      if tag?(status, headers, env)
        sha1 = Digest::SHA1.hexdigest(body)
        Merb.logger.info! "Set ETag to #{sha1}"
        headers['ETag'] = sha1
      end

      [status, headers, body]
    end

    def tag?(status, headers, env)
      status == 200
    end
  end


  class Deflate < ::Merb::Rack::Middleware
    def call(env)
      status, headers, body = @app.call(env)

      if tag?(status, headers, env)
        require "zlib"
        Merb.logger.info! "Compressing response body using deflate"
        body = Zlib::Deflate.new.deflate(body, Zlib::BEST_COMPRESSION)
        headers['Content-Encoding'] = 'deflate'
      end

      [status, headers, body]
    end

    def tag?(status, headers, env)
      Merb.logger.info! "Verifying accept encoding: #{env['HTTP_ACCEPT_ENCODING']}"
      env['HTTP_ACCEPT_ENCODING'] =~ /deflate/
    end
  end  
end