Introduce ConnectionFactory

In the future we would like to use multiple threads. Every thread
will obtain requests from separate `ZMQ` connection as it is
recommended in the tutorial. Because of that we will have to
create the sockets for every thread. For that reason `Handler` takes
now in constructor a factory capable of creating new `Connection`
instead of the `Connection` itself.

`Connection#connection` method is introduced so that `Connection` has
interface compatible with `ConnectionFactory` and can be used
instead returning always `self` whenever `connection` is needed. That
should work fine for simplest testing case or in single-threaded
environment.

Author: paneq

example/http_0mq.rb

@@ -39,6 +39,6 @@ def process(request)
 pull_port = "tcp://127.0.0.1:9999"
 pub_port  = "tcp://127.0.0.1:9998"
 
-handler   = Http0MQHandler.for(sender_id, pull_port, pub_port)
+handler   = Http0MQHandler.new(M2R::ConnectionFactory.new(sender_id, pull_port, pub_port))
 handler.listen
 

lib/m2r.rb

@@ -18,4 +18,5 @@ def zmq_context(threads = 1)
 require 'm2r/request'
 require 'm2r/response'
 require 'm2r/connection'
+require 'm2r/connection_factory'
 require 'm2r/handler'

lib/m2r/connection.rb

@@ -3,25 +3,19 @@
 module M2R
   class Connection
 
-    def initialize(request_socket, response_socket)
+    def initialize(request_socket, response_socket, request_parser = Request)
       @request_socket  = request_socket
       @response_socket = response_socket
+      @request_parser  = request_parser
     end
 
-    def self.for(sender_id, request_addr, response_addr, context = M2R.zmq_context)
-      request_socket = context.socket(ZMQ::PULL)
-      request_socket.connect(request_addr)
-
-      response_socket = context.socket(ZMQ::PUB)
-      response_socket.connect(response_addr)
-      response_socket.setsockopt(ZMQ::IDENTITY, sender_id)
-
-      new(request_socket, response_socket)
+    def connection
+      self
     end
 
     def receive
       @request_socket.recv_string(msg = "")
-      Request.parse(msg)
+      @request_parser.parse(msg)
     end
 
     def reply(request, response_or_string)

lib/m2r/connection_factory.rb

@@ -0,0 +1,26 @@
+require 'm2r'
+
+module M2R
+  class ConnectionFactory
+
+    def initialize(sender_id, request_addr, response_addr, request_parser = Request, context = M2R.zmq_context)
+      @sender_id      = sender_id.to_s
+      @request_addr   = request_addr.to_s
+      @response_addr  = response_addr.to_s
+      @request_parser = request_parser
+      @context        = context
+    end
+
+    def connection
+      request_socket = @context.socket(ZMQ::PULL)
+      request_socket.connect(@request_addr)
+
+      response_socket = @context.socket(ZMQ::PUB)
+      response_socket.connect(@response_addr)
+      response_socket.setsockopt(ZMQ::IDENTITY, @sender_id)
+
+      Connection.new(request_socket, response_socket, @request_parser)
+    end
+
+  end
+end

lib/m2r/handler.rb

@@ -4,12 +4,8 @@ module M2R
   class Handler
     attr_accessor :connection
 
-    def initialize(connection)
-      @connection = connection
-    end
-
-    def self.for(sender_uuid, subscribe_address, publish_address)
-      new(Connection.for(sender_uuid, subscribe_address, publish_address))
+    def initialize(connection_factory)
+      @connection = connection_factory.connection
     end
 
     # Callback for when the handler is waiting for a request

lib/m2r/rack_handler.rb

@@ -5,17 +5,13 @@ module M2R
   class RackHandler < Handler
     attr_accessor :app
 
-    def initialize(app, connection)
+    def initialize(app, connection_factory)
       @app = app
-      super(connection)
+      super(connection_factory)
 
       trap('INT') { stop }
     end
 
-    def self.for(app, sender_uuid, subscribe_address, publish_address)
-      new(app, Connection.for(sender_uuid, subscribe_address, publish_address))
-    end
-
     def process(request)
       script_name = request.pattern.split('(', 2).first.gsub(/\/$/, '')
 

lib/rack/handler/mongrel2.rb

@@ -1,19 +1,21 @@
 require 'rack/handler'
 require 'm2r/rack_handler'
 require 'securerandom'
+require 'ostruct'
 
 module Rack
   module Handler
     class Mongrel2
       DEFAULT_OPTIONS = {
-        :recv_addr => 'tcp://127.0.0.1:9997',
-        :send_addr => 'tcp://127.0.0.1:9996',
-        :sender_id => SecureRandom.uuid
+        'recv_addr' => 'tcp://127.0.0.1:9997',
+        'send_addr' => 'tcp://127.0.0.1:9996',
+        'sender_id' => SecureRandom.uuid
       }
 
       def self.run(app, options = {})
-        options = DEFAULT_OPTIONS.merge(options)
-        adapter = M2R::RackHandler.for(app, options[:sender_id], options[:recv_addr], options[:send_addr])
+        options = OpenStruct.new( DEFAULT_OPTIONS.merge(options) )
+        factory = M2R::ConnectionFactory.new(options.sender_id, options.recv_addr, options.send_addr)
+        adapter = M2R::RackHandler.new(app, factory)
         adapter.listen
       end
 

test/connection_factory_test.rb

@@ -0,0 +1,29 @@
+require 'test_helper'
+require 'securerandom'
+
+module M2R
+  class ConnectionFactoryTest < MiniTest::Unit::TestCase
+    def test_factory
+      sender_id = "sid"
+      request_addr = "req"
+      response_addr = "req"
+      request_parser = Object.new
+
+      pull    = stub(:pull)
+      pub     = stub(:pub)
+      context = stub(:context)
+
+      context.expects(:socket).with(ZMQ::PULL).returns(pull)
+      context.expects(:socket).with(ZMQ::PUB).returns(pub)
+
+      pull.expects(:connect).with(request_addr)
+
+      pub.expects(:connect).with(response_addr)
+      pub.expects(:setsockopt).with(ZMQ::IDENTITY, sender_id)
+
+      Connection.expects(:new).with(pull, pub, request_parser)
+      cf = ConnectionFactory.new sender_id, request_addr, response_addr, request_parser, context
+      cf.connection
+    end
+  end
+end

test/connection_test.rb

@@ -1,22 +1,49 @@
 require 'test_helper'
+require 'securerandom'
 
 module M2R
   class ConnectionTest < MiniTest::Unit::TestCase
-    def test_receive_message
-      request_addr  = "inproc://requests"
-      response_addr = "inproc://responses"
 
-      push = M2R.zmq_context.socket(ZMQ::PUSH)
-      assert_equal 0, push.bind(request_addr), "Could not bind push socket in tests"
+    def setup
+      @request_addr  = "inproc://requests"
+      @response_addr = "inproc://responses"
+
+      @push = M2R.zmq_context.socket(ZMQ::PUSH)
+      assert_equal 0, @push.bind(@request_addr), "Could not bind push socket in tests"
+
+      @sub = M2R.zmq_context.socket(ZMQ::SUB)
+      assert_equal 0, @sub.bind(@response_addr), "Could not bind sub socket in tests"
 
-      sub = M2R.zmq_context.socket(ZMQ::SUB)
-      assert_equal 0, sub.bind(response_addr), "Could not bind sub socket in tests"
 
-      connection = Connection.for("a65c2d89-96ee-4bc9-971e-59b38ae24645", request_addr, response_addr)
+      @request_socket = M2R.zmq_context.socket(ZMQ::PULL)
+      @request_socket.connect(@request_addr)
+
+      @response_socket = M2R.zmq_context.socket(ZMQ::PUB)
+      @response_socket.connect(@response_addr)
+      @response_socket.setsockopt(ZMQ::IDENTITY, @sender_id = SecureRandom.uuid)
+    end
 
-      push.send_string("1c5fd481-1121-49d8-a706-69127975db1a ebb407b2-49aa-48a5-9f96-9db121051484 / 2:{},0:,", ZMQ::NOBLOCK)
+    def teardown
+      @request_socket.close
+      @response_socket.close
+      @push.close
+      @sub.close
+    end
 
+    def test_receive_message
+      connection = Connection.new(@request_socket, @response_socket)
+      @push.send_string("1c5fd481-1121-49d8-a706-69127975db1a ebb407b2-49aa-48a5-9f96-9db121051484 / 2:{},0:,", ZMQ::NOBLOCK)
       assert_instance_of Request, connection.receive
     end
+
+    def test_different_parser
+      msg = "1c5fd481-1121-49d8-a706-69127975db1a ebb407b2-49aa-48a5-9f96-9db121051484 / 2:{},0:,"
+      parser = stub(:parser)
+      parser.expects(:parse).with(msg).returns(request = Object.new)
+      connection = Connection.new(@request_socket, @response_socket, parser)
+      @push.send_string(msg = "1c5fd481-1121-49d8-a706-69127975db1a ebb407b2-49aa-48a5-9f96-9db121051484 / 2:{},0:,", ZMQ::NOBLOCK)
+      assert_equal request, connection.receive
+    end
+
   end
 end

test/handler_test.rb

@@ -4,20 +4,23 @@ module M2R
   class HandlerTest < MiniTest::Unit::TestCase
     def test_lifecycle_for_disconnect
       connection = stub(:receive => disconnect_request)
+      connection.stubs(:connection).returns(connection)
       h = TestHandler.new(connection)
       h.listen
       assert_equal [:wait, :request, :disconnect], h.called_methods
     end
 
     def test_lifecycle_for_upload_start
       connection = stub(:receive => upload_start_request)
+      connection.stubs(:connection).returns(connection)
       h = TestHandler.new(connection)
       h.listen
       assert_equal [:wait, :request, :start], h.called_methods
     end
 
     def test_lifecycle_for_upload_done
       connection = stub(:receive => upload_done_request, :reply => nil)
+      connection.stubs(:connection).returns(connection)
       h = TestHandler.new(connection)
       h.listen
       assert_equal [:wait, :request, :done, :process, :after, :reply], h.called_methods