class Topic(object):
def __init__(self, name, message, publisher_queue=100):
self.message = message
self.name = resolve_name(name)
self.publisher = Publisher(self.name,
self.message,
queue_size=publisher_queue)
self.subscribers = {}
def __del__(self):
self.close()
def close(self):
self.publisher.unregister()
for (handler, subscriber) in self.subscribers.items():
subscriber.unregister()
def publish(self, message):
self.publisher.publish(message)
def subscribe(self, handler):
self.subscribers[handler] = Subscriber(self.name, self.message,
handler)
def unsubscribe(self, handler):
del self.subscribers[handler]
class MultiPublisher():
""" Keeps track of the clients that are using a particular publisher.
Provides an API to publish messages and register clients that are using
this publisher """
def __init__(self,
topic,
msg_type=None,
latched_client_id=None,
queue_size=100):
""" Register a publisher on the specified topic.
Keyword arguments:
topic -- the name of the topic to register the publisher to
msg_type -- (optional) the type to register the publisher as. If not
provided, an attempt will be made to infer the topic type
latch -- (optional) if a client requested this publisher to be latched,
provide the client_id of that client here
Throws:
TopicNotEstablishedException -- if no msg_type was specified by the
caller and the topic is not yet established, so a topic type cannot
be inferred
TypeConflictException -- if the msg_type was specified by the
caller and the topic is established, and the established type is
different to the user-specified msg_type
"""
# First check to see if the topic is already established
topic_type = get_topic_type(topic)[0]
# If it's not established and no type was specified, exception
if msg_type is None and topic_type is None:
raise TopicNotEstablishedException(topic)
# Use the established topic type if none was specified
if msg_type is None:
msg_type = topic_type
# Load the message class, propagating any exceptions from bad msg types
msg_class = ros_loader.get_message_class(msg_type)
# Make sure the specified msg type and established msg type are same
if topic_type is not None and topic_type != msg_class._type:
raise TypeConflictException(topic, topic_type, msg_class._type)
# Create the publisher and associated member variables
self.clients = {}
self.latched_client_id = latched_client_id
self.topic = topic
self.msg_class = msg_class
self.publisher = Publisher(topic,
msg_class,
latch=(latched_client_id != None),
queue_size=queue_size)
self.listener = PublisherConsistencyListener()
self.listener.attach(self.publisher)
def unregister(self):
""" Unregisters the publisher and clears the clients """
self.publisher.unregister()
self.clients.clear()
def verify_type(self, msg_type):
""" Verify that the publisher publishes messages of the specified type.
Keyword arguments:
msg_type -- the type to check this publisher against
Throws:
Exception -- if ros_loader cannot load the specified msg type
TypeConflictException -- if the msg_type is different than the type of
this publisher
"""
if not ros_loader.get_message_class(msg_type) is self.msg_class:
raise TypeConflictException(self.topic, self.msg_class._type,
msg_type)
return
def publish(self, msg):
""" Publish a message using this publisher.
Keyword arguments:
msg -- the dict (json) message to publish
Throws:
Exception -- propagates exceptions from message conversion if the
provided msg does not properly conform to the message type of this
publisher
"""
# First, check the publisher consistency listener to see if it's done
if self.listener.attached and self.listener.timed_out():
self.listener.detach()
# Create a message instance
inst = self.msg_class()
# Populate the instance, propagating any exceptions that may be thrown
message_conversion.populate_instance(msg, inst)
# Publish the message
self.publisher.publish(inst)
def register_client(self, client_id):
""" Register the specified client as a client of this publisher.
Keyword arguments:
client_id -- the ID of the client using the publisher
"""
self.clients[client_id] = True
def unregister_client(self, client_id):
""" Unregister the specified client from this publisher.
If the specified client_id is not a client of this publisher, nothing
happens.
Keyword arguments:
client_id -- the ID of the client to remove
"""
if client_id in self.clients:
del self.clients[client_id]
def has_clients(self):
""" Return true if there are clients to this publisher. """
return len(self.clients) != 0
class MultiPublisher():
""" Keeps track of the clients that are using a particular publisher.
Provides an API to publish messages and register clients that are using
this publisher """
def __init__(self, topic, msg_type=None, latched_client_id=None, queue_size=100):
""" Register a publisher on the specified topic.
Keyword arguments:
topic -- the name of the topic to register the publisher to
msg_type -- (optional) the type to register the publisher as. If not
provided, an attempt will be made to infer the topic type
latch -- (optional) if a client requested this publisher to be latched,
provide the client_id of that client here
Throws:
TopicNotEstablishedException -- if no msg_type was specified by the
caller and the topic is not yet established, so a topic type cannot
be inferred
TypeConflictException -- if the msg_type was specified by the
caller and the topic is established, and the established type is
different to the user-specified msg_type
"""
# First check to see if the topic is already established
topic_type = get_topic_type(topic)[0]
# If it's not established and no type was specified, exception
if msg_type is None and topic_type is None:
raise TopicNotEstablishedException(topic)
# Use the established topic type if none was specified
if msg_type is None:
msg_type = topic_type
# Load the message class, propagating any exceptions from bad msg types
msg_class = ros_loader.get_message_class(msg_type)
# Make sure the specified msg type and established msg type are same
if topic_type is not None and topic_type != msg_class._type:
raise TypeConflictException(topic, topic_type, msg_class._type)
# Create the publisher and associated member variables
self.clients = {}
self.latched_client_id = latched_client_id
self.topic = topic
self.msg_class = msg_class
self.publisher = Publisher(topic, msg_class, latch=(latched_client_id!=None), queue_size=queue_size)
self.listener = PublisherConsistencyListener()
self.listener.attach(self.publisher)
def unregister(self):
""" Unregisters the publisher and clears the clients """
self.publisher.unregister()
self.clients.clear()
def verify_type(self, msg_type):
""" Verify that the publisher publishes messages of the specified type.
Keyword arguments:
msg_type -- the type to check this publisher against
Throws:
Exception -- if ros_loader cannot load the specified msg type
TypeConflictException -- if the msg_type is different than the type of
this publisher
"""
if not ros_loader.get_message_class(msg_type) is self.msg_class:
raise TypeConflictException(self.topic,
self.msg_class._type, msg_type)
return
def publish(self, msg):
""" Publish a message using this publisher.
Keyword arguments:
msg -- the dict (json) message to publish
Throws:
Exception -- propagates exceptions from message conversion if the
provided msg does not properly conform to the message type of this
publisher
"""
# First, check the publisher consistency listener to see if it's done
if self.listener.attached and self.listener.timed_out():
self.listener.detach()
# Create a message instance
inst = self.msg_class()
# Populate the instance, propagating any exceptions that may be thrown
message_conversion.populate_instance(msg, inst)
# Publish the message
self.publisher.publish(inst)
def register_client(self, client_id):
""" Register the specified client as a client of this publisher.
Keyword arguments:
client_id -- the ID of the client using the publisher
"""
self.clients[client_id] = True
def unregister_client(self, client_id):
""" Unregister the specified client from this publisher.
If the specified client_id is not a client of this publisher, nothing
happens.
Keyword arguments:
client_id -- the ID of the client to remove
"""
if client_id in self.clients:
del self.clients[client_id]
def has_clients(self):
""" Return true if there are clients to this publisher. """
return len(self.clients) != 0
