Class: MQTT::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/mqtt/client.rb

Constant Summary collapse

SELECT_TIMEOUT =

Timeout between select polls (in seconds)

0.5
ATTR_DEFAULTS =

Default attribute values

{
  :host => nil,
  :port => nil,
  :version => '3.1.1',
  :keep_alive => 15,
  :clean_session => true,
  :client_id => nil,
  :ack_timeout => 5,
  :connect_timeout => 30,
  :username => nil,
  :password => nil,
  :will_topic => nil,
  :will_payload => nil,
  :will_qos => 0,
  :will_retain => false,
  :ssl => false,
  :verify_host => true
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Client

Create a new MQTT Client instance

Accepts one of the following:

  • a URI that uses the MQTT scheme

  • a hostname and port

  • a Hash containing attributes to be set on the new instance

If no arguments are given then the method will look for a URI in the MQTT_SERVER environment variable.

Examples:

client = MQTT::Client.new
client = MQTT::Client.new('mqtt://myserver.example.com')
client = MQTT::Client.new('mqtt://user:[email protected]')
client = MQTT::Client.new('myserver.example.com')
client = MQTT::Client.new('myserver.example.com', 18830)
client = MQTT::Client.new(:host => 'myserver.example.com')
client = MQTT::Client.new(:host => 'myserver.example.com', :keep_alive => 30)

Raises:

  • (ArgumentError) 


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# File 'lib/mqtt/client.rb', line 136

def initialize(*args)
  attributes = args.last.is_a?(Hash) ? args.pop : {}

  # Set server URI from environment if present
  attributes.merge!(parse_uri(ENV['MQTT_SERVER'])) if args.length.zero? && ENV['MQTT_SERVER']

  if args.length >= 1
    case args[0]
    when URI
      attributes.merge!(parse_uri(args[0]))
    when %r{^mqtts?://}
      attributes.merge!(parse_uri(args[0]))
    else
      attributes[:host] = args[0]
    end
  end

  if args.length >= 2
    attributes[:port] = args[1] unless args[1].nil?
  end

  raise ArgumentError, 'Unsupported number of arguments' if args.length >= 3

  # Merge arguments with default values for attributes
  ATTR_DEFAULTS.merge(attributes).each_pair do |k, v|
    send("#{k}=", v)
  end

  # Set a default port number
  if @port.nil?
    @port = @ssl ? MQTT::DEFAULT_SSL_PORT : MQTT::DEFAULT_PORT
  end

  if @ssl
    require 'openssl'
    require 'mqtt/openssl_fix'
  end

  # Initialise private instance variables
  @last_ping_request = current_time
  @last_ping_response = current_time
  @socket = nil
  @read_queue = Queue.new
  @pubacks = {}
  @read_thread = nil
  @write_semaphore = Mutex.new
  @pubacks_semaphore = Mutex.new
end

Instance Attribute Details

#ack_timeout ⇒ Object

Number of seconds to wait for acknowledgement packets (default is 5 seconds)



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# File 'lib/mqtt/client.rb', line 39

def ack_timeout
  @ack_timeout
end

#clean_session ⇒ Object

Set the ‘Clean Session’ flag when connecting? (default is true)



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# File 'lib/mqtt/client.rb', line 33

def clean_session
  @clean_session
end

#client_id ⇒ Object

Client Identifier



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# File 'lib/mqtt/client.rb', line 36

def client_id
  @client_id
end

#connect_timeout ⇒ Object

Number of seconds to connect to the server (default is 90 seconds)



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# File 'lib/mqtt/client.rb', line 42

def connect_timeout
  @connect_timeout
end

#host ⇒ Object

Hostname of the remote server



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# File 'lib/mqtt/client.rb', line 8

def host
  @host
end

#keep_alive ⇒ Object

Time (in seconds) between pings to remote server (default is 15 seconds)



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# File 'lib/mqtt/client.rb', line 30

def keep_alive
  @keep_alive
end

#last_ping_response ⇒ Object (readonly)

Last ping response time



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# File 'lib/mqtt/client.rb', line 63

def last_ping_response
  @last_ping_response
end

#password ⇒ Object

Password to authenticate to the server with



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# File 'lib/mqtt/client.rb', line 48

def password
  @password
end

#port ⇒ Object

Port number of the remote server



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# File 'lib/mqtt/client.rb', line 11

def port
  @port
end

#ssl ⇒ Object

Set to true to enable SSL/TLS encrypted communication

Set to a symbol to use a specific variant of SSL/TLS. Allowed values include:

Examples:

Using TLS 1.0

client = Client.new('mqtt.example.com', :ssl => :TLSv1)

See Also:

  • OpenSSL::SSL::SSLContext::METHODS


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# File 'lib/mqtt/client.rb', line 24

def ssl
  @ssl
end

#username ⇒ Object

Username to authenticate to the server with



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# File 'lib/mqtt/client.rb', line 45

def username
  @username
end

#verify_host ⇒ Object

Set to false to skip tls hostname verification



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# File 'lib/mqtt/client.rb', line 27

def verify_host
  @verify_host
end

#version ⇒ Object

The version number of the MQTT protocol to use (default 3.1.1)



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# File 'lib/mqtt/client.rb', line 14

def version
  @version
end

#will_payload ⇒ Object

Contents of message that is sent by server when client disconnect



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# File 'lib/mqtt/client.rb', line 54

def will_payload
  @will_payload
end

#will_qos ⇒ Object

The QoS level of the will message sent by the server



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# File 'lib/mqtt/client.rb', line 57

def will_qos
  @will_qos
end

#will_retain ⇒ Object

If the Will message should be retain by the server after it is sent



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# File 'lib/mqtt/client.rb', line 60

def will_retain
  @will_retain
end

#will_topic ⇒ Object

The topic that the Will message is published to



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# File 'lib/mqtt/client.rb', line 51

def will_topic
  @will_topic
end

Class Method Details

.connect(*args, &block) ⇒ Object

Create and connect a new MQTT Client

Accepts the same arguments as creating a new client. If a block is given, then it will be executed before disconnecting again.

Example:

MQTT::Client.connect('myserver.example.com') do |client|
  # do stuff here
end



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# File 'lib/mqtt/client.rb', line 98

def self.connect(*args, &block)
  client = MQTT::Client.new(*args)
  client.connect(&block)
  client
end

.generate_client_id(prefix = 'ruby', length = 16) ⇒ Object

Generate a random client identifier (using the characters 0-9 and a-z)



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# File 'lib/mqtt/client.rb', line 106

def self.generate_client_id(prefix = 'ruby', length = 16)
  str = prefix.dup
  length.times do
    num = rand(36)
    # Adjust based on number or letter.
    num += num < 10 ? 48 : 87
    str += num.chr
  end
  str
end

Instance Method Details

#ca_file=(path) ⇒ Object

Set a path to a file containing a PEM-format CA certificate and enable peer verification



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# File 'lib/mqtt/client.rb', line 213

def ca_file=(path)
  ssl_context.ca_file = path
  ssl_context.verify_mode = OpenSSL::SSL::VERIFY_PEER unless path.nil?
end

#cert=(cert) ⇒ Object

PEM-format client certificate



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# File 'lib/mqtt/client.rb', line 196

def cert=(cert)
  ssl_context.cert = OpenSSL::X509::Certificate.new(cert)
end

#cert_file=(path) ⇒ Object

Set a path to a file containing a PEM-format client certificate



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# File 'lib/mqtt/client.rb', line 191

def cert_file=(path)
  self.cert = File.read(path)
end

#clear_queue ⇒ Object

Clear the incoming message queue.



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# File 'lib/mqtt/client.rb', line 452

def clear_queue
  @read_queue.clear
end

#connect(clientid = nil) ⇒ Object

Connect to the MQTT server If a block is given, then yield to that block and then disconnect again.



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# File 'lib/mqtt/client.rb', line 231

def connect(clientid = nil)
  @client_id = clientid unless clientid.nil?

  if @client_id.nil? || @client_id.empty?
    raise 'Must provide a client_id if clean_session is set to false' unless @clean_session

    # Empty client id is not allowed for version 3.1.0
    @client_id = MQTT::Client.generate_client_id if @version == '3.1.0'
  end

  raise 'No MQTT server host set when attempting to connect' if @host.nil?

  unless connected?
    # Create network socket
    tcp_socket = open_tcp_socket

    if @ssl
      # Set the protocol version
      ssl_context.ssl_version = @ssl if @ssl.is_a?(Symbol)

      @socket = OpenSSL::SSL::SSLSocket.new(tcp_socket, ssl_context)
      @socket.sync_close = true

      # Set hostname on secure socket for Server Name Indication (SNI)
      @socket.hostname = @host if @socket.respond_to?(:hostname=)

      @socket.connect

      @socket.post_connection_check(@host) if @verify_host
    else
      @socket = tcp_socket
    end

    # Construct a connect packet
    packet = MQTT::Packet::Connect.new(
      :version => @version,
      :clean_session => @clean_session,
      :keep_alive => @keep_alive,
      :client_id => @client_id,
      :username => @username,
      :password => @password,
      :will_topic => @will_topic,
      :will_payload => @will_payload,
      :will_qos => @will_qos,
      :will_retain => @will_retain
    )

    # Send packet
    send_packet(packet)

    # Receive response
    receive_connack

    # Start packet reading thread
    @read_thread = Thread.new(Thread.current) do |parent|
      Thread.current[:parent] = parent
      receive_packet while connected?
    end
  end

  return unless block_given?

  # If a block is given, then yield and disconnect
  begin
    yield(self)
  ensure
    disconnect
  end
end

#connected? ⇒ Boolean

Checks whether the client is connected to the server.

Returns:

  • (Boolean) 


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# File 'lib/mqtt/client.rb', line 321

def connected?
  !@socket.nil? && !@socket.closed?
end

#disconnect(send_msg = true) ⇒ Object

Disconnect from the MQTT server. If you don’t want to say goodbye to the server, set send_msg to false.



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# File 'lib/mqtt/client.rb', line 303

def disconnect(send_msg = true)
  # Stop reading packets from the socket first
  @read_thread.kill if @read_thread && @read_thread.alive?
  @read_thread = nil

  return unless connected?

  # Close the socket if it is open
  if send_msg
    packet = MQTT::Packet::Disconnect.new
    send_packet(packet)
  end
  @socket.close unless @socket.nil?
  handle_close
  @socket = nil
end

#get(topic = nil, options = {}) ⇒ Object

Return the next message received from the MQTT server. An optional topic can be given to subscribe to.

The method either returns the topic and message as an array:

topic,message = client.get

Or can be used with a block to keep processing messages:

client.get('test') do |topic,payload|
  # Do stuff here
end



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# File 'lib/mqtt/client.rb', line 395

def get(topic = nil, options = {})
  if block_given?
    get_packet(topic) do |packet|
      yield(packet.topic, packet.payload) unless packet.retain && options[:omit_retained]
    end
  else
    loop do
      # Wait for one packet to be available
      packet = get_packet(topic)
      return packet.topic, packet.payload unless packet.retain && options[:omit_retained]
    end
  end
end

#get_packet(topic = nil) ⇒ Object

Return the next packet object received from the MQTT server. An optional topic can be given to subscribe to.

The method either returns a single packet:

packet = client.get_packet
puts packet.topic

Or can be used with a block to keep processing messages:

client.get_packet('test') do |packet|
  # Do stuff here
  puts packet.topic
end



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# File 'lib/mqtt/client.rb', line 422

def get_packet(topic = nil)
  # Subscribe to a topic, if an argument is given
  subscribe(topic) unless topic.nil?

  if block_given?
    # Loop forever!
    loop do
      packet = @read_queue.pop
      yield(packet)
      puback_packet(packet) if packet.qos > 0
    end
  else
    # Wait for one packet to be available
    packet = @read_queue.pop
    puback_packet(packet) if packet.qos > 0
    return packet
  end
end

#key=(*args) ⇒ Object

Set to a PEM-format client private key



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# File 'lib/mqtt/client.rb', line 207

def key=(*args)
  cert, passphrase = args.flatten
  ssl_context.key = OpenSSL::PKey.read(cert, passphrase)
end

#key_file=(*args) ⇒ Object

Set a path to a file containing a PEM-format client private key



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# File 'lib/mqtt/client.rb', line 201

def key_file=(*args)
  path, passphrase = args.flatten
  ssl_context.key = OpenSSL::PKey.read(File.binread(path), passphrase)
end

#publish(topic, payload = '', retain = false, qos = 0) ⇒ Object

Publish a message on a particular topic to the MQTT server.

Raises:

  • (ArgumentError) 


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# File 'lib/mqtt/client.rb', line 326

def publish(topic, payload = '', retain = false, qos = 0)
  raise ArgumentError, 'Topic name cannot be nil' if topic.nil?
  raise ArgumentError, 'Topic name cannot be empty' if topic.empty?

  packet = MQTT::Packet::Publish.new(
    :id => next_packet_id,
    :qos => qos,
    :retain => retain,
    :topic => topic,
    :payload => payload
  )

  queue = qos.zero? ? nil : wait_for_puback(packet.id)

  res = send_packet(packet)

  return unless queue

  deadline = current_time + @ack_timeout

  loop do
    response = queue.pop
    case response
    when :read_timeout
      return -1 if current_time > deadline
    when :close
      return -1
    else
      @pubacks_semaphore.synchronize do
        @pubacks.delete packet.id
      end
      break
    end
  end

  res
end

#queue_empty? ⇒ Boolean

Returns true if the incoming message queue is empty.

Returns:

  • (Boolean) 


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# File 'lib/mqtt/client.rb', line 442

def queue_empty?
  @read_queue.empty?
end

#queue_length ⇒ Object

Returns the length of the incoming message queue.



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# File 'lib/mqtt/client.rb', line 447

def queue_length
  @read_queue.length
end

#remote_host ⇒ Object

Deprecated.

Please use #host instead



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# File 'lib/mqtt/client.rb', line 623

def remote_host
  host
end

#remote_host=(args) ⇒ Object

Deprecated.

Please use #host= instead



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# File 'lib/mqtt/client.rb', line 628

def remote_host=(args)
  self.host = args
end

#remote_port ⇒ Object

Deprecated.

Please use #port instead



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# File 'lib/mqtt/client.rb', line 633

def remote_port
  port
end

#remote_port=(args) ⇒ Object

Deprecated.

Please use #port= instead



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# File 'lib/mqtt/client.rb', line 638

def remote_port=(args)
  self.port = args
end

#set_will(topic, payload, retain = false, qos = 0) ⇒ Object

Set the Will for the client

The will is a message that will be delivered by the server when the client dies. The Will must be set before establishing a connection to the server



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# File 'lib/mqtt/client.rb', line 222

def set_will(topic, payload, retain = false, qos = 0)
  self.will_topic = topic
  self.will_payload = payload
  self.will_retain = retain
  self.will_qos = qos
end

#ssl_context ⇒ Object

Get the OpenSSL context, that is used if SSL/TLS is enabled



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# File 'lib/mqtt/client.rb', line 186

def ssl_context
  @ssl_context ||= OpenSSL::SSL::SSLContext.new
end

#subscribe(*topics) ⇒ Object

Send a subscribe message for one or more topics on the MQTT server. The topics parameter should be one of the following:

  • String: subscribe to one topic with QoS 0

  • Array: subscribe to multiple topics with QoS 0

  • Hash: subscribe to multiple topics where the key is the topic and the value is the QoS level

For example:

client.subscribe( 'a/b' )
client.subscribe( 'a/b', 'c/d' )
client.subscribe( ['a/b',0], ['c/d',1] )
client.subscribe( 'a/b' => 0, 'c/d' => 1 )



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# File 'lib/mqtt/client.rb', line 376

def subscribe(*topics)
  packet = MQTT::Packet::Subscribe.new(
    :id => next_packet_id,
    :topics => topics
  )
  send_packet(packet)
end

#unsubscribe(*topics) ⇒ Object

Send a unsubscribe message for one or more topics on the MQTT server



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# File 'lib/mqtt/client.rb', line 457

def unsubscribe(*topics)
  topics = topics.first if topics.is_a?(Enumerable) && topics.count == 1

  packet = MQTT::Packet::Unsubscribe.new(
    :topics => topics,
    :id => next_packet_id
  )
  send_packet(packet)
end