Add fake MQTT server from ruby-mqtt gem

spec/support/fake_mqtt_server.rb

@@ -0,0 +1,131 @@
+#!/usr/bin/env ruby
+#
+# This is a 'fake' MQTT server to help with testing client implementations
+#
+# See https://github.com/njh/ruby-mqtt/blob/master/spec/fake_server.rb
+#
+# It behaves in the following ways:
+#   * Responses to CONNECT with a successful CONACK
+#   * Responses to PUBLISH by echoing the packet back
+#   * Responses to SUBSCRIBE with SUBACK and a PUBLISH to the topic
+#   * Responses to PINGREQ with PINGRESP
+#   * Responses to DISCONNECT by closing the socket
+#
+# It has the following restrictions
+#   * Doesn't deal with timeouts
+#   * Only handles a single connection at a time
+#
+
+$:.unshift File.dirname(__FILE__)+'/../lib'
+
+require 'logger'
+require 'socket'
+require 'mqtt'
+
+
+class MQTT::FakeServer
+  attr_reader :address, :port
+  attr_reader :last_publish
+  attr_reader :thread
+  attr_reader :pings_received
+  attr_accessor :just_one
+  attr_accessor :logger
+
+  # Create a new fake MQTT server
+  #
+  # If no port is given, bind to a random port number
+  # If no bind address is given, bind to localhost
+  def initialize(port=nil, bind_address='127.0.0.1')
+    @port = port
+    @address = bind_address
+  end
+
+  # Get the logger used by the server
+  def logger
+    @logger ||= Logger.new(STDOUT)
+  end
+
+  # Start the thread and open the socket that will process client connections
+  def start
+    @socket ||= TCPServer.new(@address, @port)
+    @address = @socket.addr[3]
+    @port = @socket.addr[1]
+    @thread ||= Thread.new do
+      logger.info "Started a fake MQTT server on #{@address}:#{@port}"
+      loop do
+        # Wait for a client to connect
+        client = @socket.accept
+        @pings_received = 0
+        handle_client(client)
+        break if just_one
+      end
+    end
+  end
+
+  # Stop the thread and close the socket
+  def stop
+    logger.info "Stopping fake MQTT server"
+    @socket.close unless @socket.nil?
+    @socket = nil
+
+    @thread.kill if @thread and @thread.alive?
+    @thread = nil
+  end
+
+  # Start the server thread and wait for it to finish (possibly never)
+  def run
+    start
+    begin
+      @thread.join
+    rescue Interrupt
+      stop
+    end
+  end
+
+
+  protected
+
+  # Given a client socket, process MQTT packets from the client
+  def handle_client(client)
+    loop do
+      packet = MQTT::Packet.read(client)
+      logger.debug packet.inspect
+
+      case packet
+        when MQTT::Packet::Connect
+          client.write MQTT::Packet::Connack.new(:return_code => 0)
+        when MQTT::Packet::Publish
+          client.write packet
+          @last_publish = packet
+        when MQTT::Packet::Subscribe
+          client.write MQTT::Packet::Suback.new(
+            :message_id => packet.message_id,
+            :granted_qos => 0
+          )
+          topic = packet.topics[0][0]
+          client.write MQTT::Packet::Publish.new(
+            :topic => topic,
+            :payload => "hello #{topic}",
+            :retain => true
+          )
+        when MQTT::Packet::Pingreq
+          client.write MQTT::Packet::Pingresp.new
+          @pings_received += 1
+        when MQTT::Packet::Disconnect
+          client.close
+        break
+      end
+    end
+
+    rescue MQTT::ProtocolException => e
+      logger.warn "Protocol error, closing connection: #{e}"
+      client.close
+  end
+
+end
+
+if __FILE__ == $0
+  server = MQTT::FakeServer.new(MQTT::DEFAULT_PORT)
+  server.logger.level = Logger::DEBUG
+  server.run
+end