exmqttc v0.6.0 Exmqttc
Exmqttc
provides a connection to a MQTT server based on emqttc
Link to this section Summary
Types
A PID like type
A QoS level
A single topic, a list of topics or a list of tuples of topic and QoS level
Functions
Returns a specification to start this module under a supervisor
Disconnect socket from MQTT server
Invoked when the server is started. start_link/3
or start/3
will
block until it returns
Publish a message to MQTT.
opts
is a keywordlist and supports :retain
with a boolean and :qos
with an integer from 1 to 3
Start the Exmqttc client. callback_module
is used for callbacks and should implement the Exmqttc.Callback
behaviour.
opts
are passed directly to GenServer.
mqtt_opts
are reformatted so all options can be passed in as a Keyworld list.
Params are passed to your callbacks init function
Subscribe to the given topic(s) given as topics
with a given qos
Publish a message to MQTT synchronously.
opts
is a keywordlist and supports :retain
with a boolean and :qos
with an integer from 1 to 3
Subscribe to the given topics while blocking until the subscribtion has been confirmed by the server
Unsubscribe from the given topic(s) given as topics
Link to this section Types
A QoS level
A single topic, a list of topics or a list of tuples of topic and QoS level
Link to this section Functions
Returns a specification to start this module under a supervisor.
See Supervisor
.
Disconnect socket from MQTT server
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
args
is the argument term (second argument) passed to start_link/3
.
Returning {:ok, state}
will cause start_link/3
to return
{:ok, pid}
and the process to enter its loop.
Returning {:ok, state, timeout}
is similar to {:ok, state}
except handle_info(:timeout, state)
will be called after timeout
milliseconds if no messages are received within the timeout.
Returning {:ok, state, :hibernate}
is similar to
{:ok, state}
except the process is hibernated before entering the loop. See
c:handle_call/3
for more information on hibernation.
Returning :ignore
will cause start_link/3
to return :ignore
and the
process will exit normally without entering the loop or calling c:terminate/2
.
If used when part of a supervision tree the parent supervisor will not fail
to start nor immediately try to restart the GenServer
. The remainder of the
supervision tree will be (re)started and so the GenServer
should not be
required by other processes. It can be started later with
Supervisor.restart_child/2
as the child specification is saved in the parent
supervisor. The main use cases for this are:
- The
GenServer
is disabled by configuration but might be enabled later. - An error occurred and it will be handled by a different mechanism than the
Supervisor
. Likely this approach involves callingSupervisor.restart_child/2
after a delay to attempt a restart.
Returning {:stop, reason}
will cause start_link/3
to return
{:error, reason}
and the process to exit with reason reason
without
entering the loop or calling c:terminate/2
.
Callback implementation for GenServer.init/1
.
Publish a message to MQTT.
opts
is a keywordlist and supports :retain
with a boolean and :qos
with an integer from 1 to 3
Start the Exmqttc client. callback_module
is used for callbacks and should implement the Exmqttc.Callback
behaviour.
opts
are passed directly to GenServer.
mqtt_opts
are reformatted so all options can be passed in as a Keyworld list.
Params are passed to your callbacks init function.
mqtt_opts
supports the following options:
host
: Connection host, charlist, default:'localhost'
port
: Connection port, integer, default 1883client_id
: Binary ID for client, automatically set to UUID if not specifiedclean_sess
: MQTT cleanSession flag.true
disables persistent sessions on the serverkeepalive
: Keepalive timer, integerusername
: Login username, binarypassword
: Login password, binarywill
: Last will, keywordlist, sample:[qos: 1, retain: false, topic: "WillTopic", payload: "I died"]
connack_timeout
: Timeout for connack package, integer, default 60puback_timeout
: Timeout for puback package, integer, default 8suback_timeout
: Timeout for suback package, integer, default 4ssl
: List of ssl optionsauto_resub
: Automatically resubscribe to topics, boolean, default:false
reconnect
: Automatically reconnect on lost connection, integer (), defaultfalse
Subscribe to the given topic(s) given as topics
with a given qos
.
Publish a message to MQTT synchronously.
opts
is a keywordlist and supports :retain
with a boolean and :qos
with an integer from 1 to 3
Subscribe to the given topics while blocking until the subscribtion has been confirmed by the server.
Unsubscribe from the given topic(s) given as topics
.