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Mark Hindess

NAME

AnyEvent::MQTT - AnyEvent module for an MQTT client

VERSION

version 1.172121

SYNOPSIS

  use AnyEvent::MQTT;
  my $mqtt = AnyEvent::MQTT->new;
  my $cv = $mqtt->subscribe(topic => '/topic',
                            callback => sub {
                                 my ($topic, $message) = @_;
                                 print $topic, ' ', $message, "\n"
                               });
  my $qos = $cv->recv; # subscribed, negotiated QoS == $qos

  # publish a simple message
  $cv = $mqtt->publish(message => 'simple message',
                          topic => '/topic');
  $cv->recv; # sent

  # publish line-by-line from file handle
  $cv =  $mqtt->publish(handle => \*STDIN,
                        topic => '/topic');
  $cv->recv; # sent

  # publish from AnyEvent::Handle
  $cv = $mqtt->publish(handle => AnyEvent::Handle->new(my %handle_args),
                       topic => '/topic');
  $cv->recv; # sent

DESCRIPTION

AnyEvent module for MQTT client.

IMPORTANT: This is an early release and the API is still subject to change.

METHODS

new(%params)

Constructs a new AnyEvent::MQTT object. The supported parameters are:

host

The server host. Defaults to 127.0.0.1.

port

The server port. Defaults to 1883.

timeout

The timeout for responses from the server.

keep_alive_timer

The keep alive timer.

user_name

The user name for the MQTT broker.

password

The password for the MQTT broker.

will_topic

Set topic for will message. Default is undef which means no will message will be configured.

will_qos

Set QoS for will message. Default is 'at-most-once'.

will_retain

Set retain flag for will message. Default is 0.

will_message

Set message for will message. Default is the empty message.

clean_session

Set clean session flag for connect message. Default is 1 but it is set to 0 when reconnecting after an error.

client_id

Sets the client id for the client overriding the default which is NetMQTTpmNNNNN where NNNNN is the current process id.

message_log_callback

Defines a callback to call on every message.

on_error

Defines a callback to call when some error occurs.

Two parameters are passed to the callback.

    $on_error->($fatal, $message)

where $fatal is a boolean flag and $message is the error message. If the error is fatal, $fatal is true.

handle_args
  a reference to a list to pass as arguments to the
  L<AnyEvent::Handle> constructor (defaults to
  an empty list reference).

cleanup()

This method attempts to destroy any resources in the event of a disconnection or fatal error.

publish( %parameters )

This method is used to publish to a given topic. It returns an AnyEvent condvar which is notified when the publish is complete (written to the kernel or ack'd depending on the QoS level). The parameter hash must included at least a topic value and one of:

message
  with a string value which is published to the topic,
handle
 the value of which must either be an L<AnyEvent::Handle> or will be
 passed to an L<AnyEvent::Handle> constructor as the C<fh> argument.
 The L<push_read()> method is called on the L<AnyEvent::Handle> with a
 callback that will publish each chunk read to the topic.

The parameter hash may also keys for:

qos
  to set the QoS level for published messages (default
  MQTT_QOS_AT_MOST_ONCE),
handle_args
  a reference to a list to pass as arguments to the
  L<AnyEvent::Handle> constructor in the final case above (defaults to
  an empty list reference), or
push_read_args
  a reference to a list to pass as the arguments to the
  L<AnyEvent::Handle#push_read> method (defaults to ['line'] to read,
  and subsequently publish, a line at a time.

next_message_id()

Returns a 16-bit number to use as the next message id in a message requiring an acknowledgement.

subscribe( %parameters )

This method subscribes to the given topic. The parameter hash may contain values for the following keys:

topic
  for the topic to subscribe to (this is required),
callback
  for the callback to call with messages (this is required),
qos
  QoS level to use (default is MQTT_QOS_AT_MOST_ONCE),
cv
  L<AnyEvent> condvar to use to signal the subscription is complete.
  The received value will be the negotiated QoS level.

This method returns the value of the cv parameter if it was supplied or an AnyEvent condvar created for this purpose.

unsubscribe( %parameters )

This method unsubscribes to the given topic. The parameter hash may contain values for the following keys:

topic
  for the topic to unsubscribe from (this is required),
callback
  for the callback to call with messages (this is optional and currently
  not supported - all callbacks are unsubscribed),
cv
  L<AnyEvent> condvar to use to signal the unsubscription is complete.

This method returns the value of the cv parameter if it was supplied or an AnyEvent condvar created for this purpose.

connect( [ $msg ] )

This method starts the connection to the server. It will be called lazily when required publish or subscribe so generally is should not be necessary to call it directly.

anyevent_read_type()

This method is used to register an AnyEvent::Handle read type method to read MQTT messages.

DISCLAIMER

This is not official IBM code. I work for IBM but I'm writing this in my spare time (with permission) for fun.

AUTHOR

Mark Hindess <soft-cpan@temporalanomaly.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2014 by Mark Hindess.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.