antes.rb

class Poxy
  class RequestFactory

    def initialize(target, rack_request)
      @rp = Poxy::RequestProcessor.new(rack_request)
      method, headers, query_string, params, body = @rp.parsed
      url = fix_url(target, query_string)
      headers = fix_headers(headers)
      HTTPI.adapter = :curb
      @request = HTTPI::Request.new(
          headers: headers,
          url: url,
          body: params
      )
      begin
        @response = HTTPI.send(method.downcase.to_sym, @request)
      rescue Curl::Err::ConnectionFailedError
        @response = HTTPI::Response.new(503, {}, ["No response from server"])
      end
    end

    def response
      @response
    end

    def fix_headers(headers)
      copy = headers
      headers = {}
      copy.select {|k,v| k.downcase.start_with?("x_")}.collect { |pair| headers[pair[0]] =  pair[1] }
      headers['X-VIA'] = "Poxy 1.0, http://poxy.ws"
      headers['X-Forwarded-For'] = copy['ORIGIN']
      headers
    end

    def fix_url(target, query_string)
      if query_string.present?
        target + "?" + query_string
      else
        target
      end
    end

  end
end

despues.rb

class Poxy
  class RequestFactory

    attr_accessor :url, :method, :headers, :query_string, :body

    def initialize(target, opts = {})
      @method = opts[:method].downcase.to_sym
      @url = target
      @headers = add_via(opts[:headers])
      @query_string = opts[:query_string]
      #TODO: Add uploads from original request?
      @body = opts[:body]
      @timeout = opts[:open_timeout] || 30
      HTTPI.adapter = :curb
      @request = HTTPI::Request.new(
          url: @url,
          query: @query_string,
          headers: @headers,
          body: @body,
          open_timeout: @timeout
      )
    end

    def response
      begin
        @response = HTTPI.send(@method, @request)
      rescue Curl::Err::ConnectionFailedError
        @response = HTTPI::Response.new(503, {}, ["No response from server"])
      rescue Curl::Err::GotNothingError
        @response = HTTPI::Response.new(404, {}, ["Not found"])
      rescue NoMethodError
        @response = HTTPI::Response.new(405, {}, ["Method not allowed"])
      end      
      @response
    end

    def add_via(headers)
      headers['X-VIA'] = "Poxy 1.0, http://poxy.ws"
      headers['X-Forwarded-For'] = headers['ORIGIN']
      headers
    end

  end
end

test.rb

#poxy_request_factory

setup do
  @req_opts = { method: "GET", headers: {}, query_string: "foo=bar" , body: "", open_timeout: 1}
  @req = Poxy::RequestFactory.new('http://example.com:8080', @req_opts)
end

test "it should response a 503" do ||
  assert_equal @req.response.code, HTTPI::Response.new(503, {}, ["No response from server"]).code
end

test "url should match " do
  req = Poxy::RequestFactory.new('http://example.com:8080', @req_opts)
  assert_equal req.url, 'http://example.com:8080'
end

test "query string should match" do
  query_string = "foo=bar"
  @req_opts[:query_string] = query_string
  req = Poxy::RequestFactory.new('http://example.com:8080', @req_opts)
  assert_equal req.query_string, query_string
end

test "it should be a :get request" do
  assert_equal @req.method, @req_opts[:method].downcase.to_sym
end

test "body should be present" do
  body = { user_id: 123, active: false }
  @req_opts[:body] = body
  req = Poxy::RequestFactory.new('http://example.com:8080', @req_opts)
  assert_equal req.body, body
end

test "X-VIA should be present in request headers" do
  assert_equal @req.headers["X-VIA"], "Poxy 1.0, http://poxy.ws"
end