From 6128621ce6c8b8de14afe0b5ce93c9b169003b54 Mon Sep 17 00:00:00 2001
From: Seth Call <seth@jamkazam.com>
Date: Mon, 15 Oct 2012 21:09:57 -0500
Subject: [PATCH] * VRFS-19 - jam-ruby looks to have client messaging
 integrated, but need to see if it works when used in jam-web

---
 Gemfile                                 |  1 +
 lib/jam_ruby.rb                         |  1 +
 lib/jam_ruby/connection_cleaner.rb      |  6 +++
 lib/jam_ruby/errors/permission_error.rb |  3 ++
 lib/jam_ruby/mq_router.rb               | 58 +++++++++++++++++++++++++
 spec/jam_ruby/mq_router_spec.rb         | 48 ++++++++++++++++++++
 6 files changed, 117 insertions(+)
 create mode 100644 lib/jam_ruby/connection_cleaner.rb
 create mode 100644 lib/jam_ruby/errors/permission_error.rb
 create mode 100644 lib/jam_ruby/mq_router.rb
 create mode 100644 spec/jam_ruby/mq_router_spec.rb

diff --git a/Gemfile b/Gemfile
index 061aa233e..0dd3006c9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,6 +11,7 @@ gem 'activerecord', '3.2.7'
 gem 'uuidtools', '2.1.2'
 gem 'bcrypt-ruby', '3.0.1'
 gem 'ruby-protocol-buffers', '1.2.2'
+gem 'eventmachine'
 
 group :test do
   gem 'jam_db', :path=> "#{workspace}/jam-db/target/ruby_package"
diff --git a/lib/jam_ruby.rb b/lib/jam_ruby.rb
index 94d641d67..ad68d6f08 100644
--- a/lib/jam_ruby.rb
+++ b/lib/jam_ruby.rb
@@ -2,6 +2,7 @@ require "pg"
 require "active_record"
 require "jampb"
 require 'uuidtools'
+require "jam_ruby/mq_router"
 require "jam_ruby/version"
 require "jam_ruby/message_factory"
 require "jam_ruby/models/music_session_client"
diff --git a/lib/jam_ruby/connection_cleaner.rb b/lib/jam_ruby/connection_cleaner.rb
new file mode 100644
index 000000000..21522929d
--- /dev/null
+++ b/lib/jam_ruby/connection_cleaner.rb
@@ -0,0 +1,6 @@
+class ConnectionCleaner
+
+  def clean(connection, topic)
+
+  end
+end
\ No newline at end of file
diff --git a/lib/jam_ruby/errors/permission_error.rb b/lib/jam_ruby/errors/permission_error.rb
new file mode 100644
index 000000000..80c4b1ff6
--- /dev/null
+++ b/lib/jam_ruby/errors/permission_error.rb
@@ -0,0 +1,3 @@
+class PermissionError < Exception
+
+end
\ No newline at end of file
diff --git a/lib/jam_ruby/mq_router.rb b/lib/jam_ruby/mq_router.rb
new file mode 100644
index 000000000..b0f86b07d
--- /dev/null
+++ b/lib/jam_ruby/mq_router.rb
@@ -0,0 +1,58 @@
+require 'eventmachine'
+
+class MQRouter
+
+  # monostate pattern:
+  # You can initialize MQRouter instances as you want,
+  # but ultimately there are internal static state variables to represent global MQ exchange connections
+
+  class << self
+    attr_accessor :client_exchange, :user_exchange
+    @@log = Logging.logger[MQRouter]
+  end
+
+  def access_music_session(music_session, user)
+
+    if music_session.nil?
+      raise ArgumentError, 'specified session not found'
+    end
+
+    if !music_session.access? user
+      raise PermissionError, 'not allowed to join the specified session'
+    end
+
+    return music_session
+  end
+
+  # sends a message to a session on behalf of a user
+  # if this is originating in the context of a client, it should be specified as :client_id => "value"
+  # client_msg should be a well-structure message (jam-pb message)
+  def user_publish_to_session(music_session, user, client_msg, sender = {:client_id => "" })
+    access_music_session(music_session, user)
+
+    # gather up client_ids in the session
+    client_ids = music_session.music_session_clients.map {|client| client.client_id }.reject {|client_id| client_id == sender[:client_id] }
+
+    publish_to_session(music_session.id, client_ids, client_msg.to_s, sender)
+  end
+
+
+  # sends a message to a session with no checking of permissions
+  # this method deliberately has no database interactivity/active_record objects
+  def publish_to_session(music_session_id, client_ids, client_msg, sender = {:client_id => "" })
+
+    EM.schedule do
+      sender_client_id  = sender[:client_id]
+
+      # iterate over each person in the session, and send a p2p message
+      client_ids.each do |client_id|
+
+          @@log.debug "publishing to session:client #{music_session_id}:#{client_id} from client_id #{sender_client_id}"
+          # put it on the topic exchange for clients
+          self.class.client_exchange.publish(client_msg, :routing_key => "clients.#{music_session_id}")
+      end
+    end
+  end
+
+
+end
\ No newline at end of file
diff --git a/spec/jam_ruby/mq_router_spec.rb b/spec/jam_ruby/mq_router_spec.rb
new file mode 100644
index 000000000..76394847f
--- /dev/null
+++ b/spec/jam_ruby/mq_router_spec.rb
@@ -0,0 +1,48 @@
+require 'spec_helper'
+
+describe MQRouter do
+
+  before do
+    @mq_router = MQRouter.new()
+  end
+
+  it "user_publish_to_session works (but faking MQ)" do
+
+    user1 = FactoryGirl.create(:user)  # in the jam session
+    user2 = FactoryGirl.create(:user)  # in the jam session
+
+    music_session = FactoryGirl.create(:music_session, :creator => user1)
+
+    music_session_member1 = FactoryGirl.create(:music_session_client, :user => user1, :music_session => music_session, :ip_address => "1.1.1.1", :client_id => "1")
+    music_session_member2 = FactoryGirl.create(:music_session_client, :user => user2, :music_session => music_session, :ip_address => "2.2.2.2", :client_id => "2")
+
+    @mq_router.should_receive(:publish_to_session).with(music_session.id, [music_session_member2.client_id], "a message", :client_id => music_session_member1.client_id)
+
+    @mq_router.user_publish_to_session(music_session, user1, "a message" ,:client_id => music_session_member1.client_id)
+  end
+
+  it "user_publish_to_session works (checking exchange callbacks)" do
+
+    user1 = FactoryGirl.create(:user)  # in the jam session
+    user2 = FactoryGirl.create(:user)  # in the jam session
+
+    music_session = FactoryGirl.create(:music_session, :creator => user1)
+
+    music_session_member1 = FactoryGirl.create(:music_session_client, :user => user1, :music_session => music_session, :ip_address => "1.1.1.1", :client_id => "1")
+    music_session_member2 = FactoryGirl.create(:music_session_client, :user => user2, :music_session => music_session, :ip_address => "2.2.2.2", :client_id => "2")
+
+    EM.run do
+
+      # mock up exchange
+      MQRouter.client_exchange = double("client_exchange")
+
+      MQRouter.client_exchange.should_receive(:publish).with("a message", :routing_key => "clients.#{music_session.id}")
+
+      @mq_router.user_publish_to_session(music_session, user1, "a message", :client_id => music_session_member1.client_id)
+
+      EM.stop
+
+    end
+  end
+
+end