Publish/Subscribe API for PubNub Python SDK
The foundation of the PubNub service is the ability to send a message and have it delivered anywhere in less than 100ms. Send a message to just one other person, or broadcast to thousands of subscribers at once.
For higher-level conceptual details on publishing and subscribing, refer to Connection Management and to Publish Messages.
Request execution and return values
You can decide whether to perform the Python SDK operations synchronously or asynchronously.
-
.sync()
returns anEnvelope
object, which has two fields:Envelope.result
, whose type differs for each API, andEnvelope.status
of typePnStatus
.pubnub.publish() \
.channel("myChannel") \
.message("Hello from PubNub Python SDK") \
.sync() -
.pn_async(callback)
returnsNone
and passes the values ofEnvelope.result
andEnvelope.status
to a callback you must define beforehand.def my_callback_function(result, status):
print(f'TT: {result.timetoken}, status: {status.category.name}')
pubnub.publish() \
.channel("myChannel") \
.message("Hello from PubNub Python SDK") \
.pn_async(my_callback_function)
Publish
publish()
sends a message to all channel subscribers. A successfully published message is replicated across PubNub's points of presence and sent simultaneously to all subscribed clients on a channel.
ObjectNode
The new Jackson parser does not recognize JSONObject. Use ObjectNode instead.
- Prerequisites and limitations
- Security
- Message data
- Size
- Publish rate
- Best practices
- You must initialize PubNub with the
publishKey
. - You don't have to be subscribed to a channel to publish to it.
- You cannot publish to multiple channels simultaneously.
You can secure the messages with SSL/TLS by setting ssl
to true
during initialization. You can also encrypt messages.
The message can contain any JSON-serializable data (Objects, Arrays, Ints, Strings) and shouldn't contain any special classes or functions. String content can include any single-byte or multi-byte UTF-8 characters.
Don't JSON serialize
You should not JSON serialize the message
and meta
parameters when sending signals, messages, or files as the serialization is automatic. Pass the full object as the message/meta payload and let PubNub handle everything.
The maximum message size is 32 KiB, including the final escaped character count and the channel name. An optimal message size is under 1800 bytes.
If the message you publish exceeds the configured size, you receive a Message Too Large
error. If you want to learn more or calculate your payload size, refer to Message Size Limit.
You can publish as fast as bandwidth conditions allow. There is a soft limit based on max throughput since messages will be discarded if the subscriber can't keep pace with the publisher.
For example, if 200 messages are published simultaneously before a subscriber has had a chance to receive any, the subscriber may not receive the first 100 messages because the message queue has a limit of only 100 messages stored in memory.
- Publish to any given channel in a serial manner (not concurrently).
- Check that the return code is success (for example,
[1,"Sent","136074940..."]
) - Publish the next message only after receiving a success return code.
- If a failure code is returned (
[0,"blah","<timetoken>"]
), retry the publish. - Avoid exceeding the in-memory queue's capacity of 100 messages. An overflow situation (aka missed messages) can occur if slow subscribers fail to keep up with the publish pace in a given period of time.
- Throttle publish bursts according to your app's latency needs, for example no more than 5 messages per second.
Method(s)
To Publish a message
you can use the following method(s) in the Python SDK:
pubnub.publish() \
.channel(String) \
.message(Object) \
.should_store(Boolean) \
.meta(Dictionary) \
.use_post(Boolean)
Parameter | Type | Required | Default | Description |
---|---|---|---|---|
channel | String | Yes | Destination of message . | |
message | Object | Yes | The payload. | |
should_store | Boolean | Optional | account default | Store in history |
meta | Object | Optional | None | Meta data object which can be used with the filtering ability. |
Basic Usage
Publish a message to a channel
- Builder Pattern
- Named Arguments
from pubnub.exceptions import PubNubException
try:
envelope = pubnub.publish().channel("my_channel").message({
'name': 'Alex',
'online': True
}).sync()
print("publish timetoken: %d" % envelope.result.timetoken)
except PubNubException as e:
handle_exception(e)
from pubnub.exceptions import PubNubException
try:
publish = pubnub.publish(channel="my_channel", message={
'name': 'Alex',
'online': True
}).sync()
except PubNubException as e:
handle_exception(e)
Subscribe to the channel
Before running the above publish example, either using the Debug Console or in a separate script running in a separate terminal window, subscribe to the same channel that is being published to.
Returns
The publish()
operation returns an Envelope
which contains the following fields:
Field | Type | Description |
---|---|---|
result | PNPublishResult | A string representation of the result and the timetoken when the message was published. |
status | PNStatus | A status object with additional information. |
PNPublishResult
Publish success with timetoken 17193163560057793
Other Examples
Publish with metadata
def publish_callback(result, status):
pass
# handle publish result, status always present, result if successful
# status.is_error() to see if error happened
pubnub.publish().channel("my_channel").message(["hello", "there"]) \
.meta({'name': 'Alex'}).pn_async(publish_callback)
Fire
The fire endpoint allows the client to send a message to Functions Event Handlers and Illuminate. These messages will go directly to any Event Handlers registered on the channel that you fire to and will trigger their execution. The content of the fired request will be available for processing within the Event Handler. The message sent via fire()
isn't replicated, and so won't be received by any subscribers to the channel. The message is also not stored in history.
Method(s)
To Fire a message
you can use the following method(s) in the Python SDK:
pubnub.fire() \
.channel(String) \
.message(Object) \
.use_post(Boolean) \
.meta(Object)
Parameter | Type | Required | Default | Description |
---|---|---|---|---|
channel | String | Yes | Destination of message . | |
message | Object | Yes | The payload. | |
use_post | Boolean | Optional | False | Use POST to publish. |
meta | Object | Optional | None | Meta data object which can be used with the filtering ability. |
Basic Usage
Fire a message to a channel
- Builder Pattern
- Named Arguments
envelope = pubnub.fire() \
.channel('my_channel') \
.message('hello there') \
.use_post(True) \
.sync()
print(f'fire timetoken: {envelope.result.timetoken}')
fire = pubnub.fire(channel="my_channel", message='hello there').sync()
print(f'fire timetoken: {fire.result.timetoken}')
Returns
The fire()
operation returns an Envelope
which contains the following fields:
Field | Type | Description |
---|---|---|
result | PNFireResult | A string representation of the result and the timetoken when the message was fired. |
status | PNStatus | A status object with additional information. |
PNFireResult
Fire success with timetoken 17193163560057793
Signal
The signal()
function is used to send a signal to all subscribers of a channel.
By default, signals are limited to a message payload size of 64
bytes. This limit applies only to the payload, and not to the URI or headers. If you require a larger payload size, please contact support.
Method(s)
To Signal a message
you can use the following method(s) in the Python SDK:
pubnub.signal()
.message(Object)
.channel(String)
Parameter | Type | Required | Description |
---|---|---|---|
message | Object | Yes | The payload. |
channel | String | Yes | Destination of message . |
Basic Usage
Signal a message to a channel
- Builder Pattern
- Named Arguments
envelope = pubnub.signal() \
.channel('some_channel') \
.message('foo') \
.sync()
signal = pubnub.signal(channel="my_channel", message='hello there').sync()
print(f'signal timetoken: {signal.result.timetoken}')
Returns
The signal()
operation returns an Envelope
which contains the following fields:
Field | Type | Description |
---|---|---|
result | PNSignalResult | A string representation of the result and the timetoken when the signal was sent. |
status | PNStatus | A status object with additional information. |
PNSignalResult
Signal success with timetoken 17193165584676126
Subscribe
The subscribe function creates an open TCP socket to PubNub and begins listening for messages and events on a specified entity or set of entities. To subscribe successfully, you must configure the appropriate subscribeKey
at initialization.
Entities are first-class citizens that provide access to their encapsulated APIs. You can subscribe using the PubNub client object or directly on a specific entity:
ChannelRepresentation
ChannelGroupRepresentation
UserMetadataRepresentation
ChannelMetadataRepresentation
A newly subscribed client receives messages after the subscribe()
call completes. You can configure automatic retries to attempt to reconnect automatically and retrieve any available messages if a client gets disconnected.
Subscription scope
Subscription objects provide an interface to attach listeners for various real-time update types. Your app receives messages and events via those event listeners. Two types of subscriptions are available:
Subscription
, created from an entity with a scope of only that entity (for example, a particular channel)SubscriptionSet
, created from the PubNub client with a global scope (for example, all subscriptions created on a singlepubnub
object ). A subscription set can have one or more subscriptions.
The event listener is a single point through which your app receives all the messages, signals, and events in the entities you subscribed to. For information on adding event listeners, refer to Event listeners.
Create a subscription
An entity-level Subscription
allows you to receive messages and events for only that entity for which it was created. Using multiple entity-level Subscription
s is useful for handling various message/event types differently in each channel.
# entity-based, local-scoped
subscription = pubnub.channel(f'{channel}').subscription(with_presence: bool = False)
Parameter | Type | Required | Description |
---|---|---|---|
with_presence | bool | No | Whether presence updates for userId should be delivered through the listener streams. |
Create a subscription set
A client-level SubscriptionSet
allows you to receive messages and events for all entities. A single SubscriptionSet
is useful for similarly handling various message/event types in each channel.
# client-based, general-scoped
subscription_set = pubnub.subscription_set(subscriptions: List[PubNubSubscription])
Parameter | Type | Required | Description |
---|---|---|---|
subscriptions | List[PubNubSubscription] | Yes | Channels/Channel group subscriptions. |
Method(s)
Subscription
and SubscriptionSet
use the same subscribe()
method.
Subscribe
To subscribe, you can use the following method in the Python SDK:
subscription.subscribe(timetoken: Optional[int] = None, region: Optional[str] = None,)
Parameter | Type | Required | Description |
---|---|---|---|
timetoken | int | No | Timetoken from which to return any available cached messages. Message retrieval with timetoken is not guaranteed and should only be considered a best-effort service. If the value is not a 17-digit number, the provided value will be ignored. |
region | String | No | The region the message was published in. |
Basic usage
# single channel subscription
channel = pubnub.channel(f'{channel}')
t1_subscription = channel.subscription()
t1_subscription.subscribe()
# multiple channel subscription
channel_1 = pubnub.channel(channel).subscription()
channel_2 = pubnub.channel(f'{channel}.2').subscription(with_presence=True)
channel_x = pubnub.channel(f'{channel}.*').subscription(with_presence=True)
group = pubnub.channel_group('group-test').subscription()
subscription_set = pubnub.subscription_set([channel_1, channel_2, channel_x, group])
set_subscription = subscription_set.subscribe()
Returns
The subscribe()
method doesn't have a return value.
Entities
Entities are subscribable objects for which you can receive real-time updates (messages, events, etc).
Create channels
This method returns a local PubNubChannel
entity.
pubnub.channel(String)
Parameter | Type | Required | Description |
---|---|---|---|
channel | String | Yes | The name of the channel to create a subscription of. |
Basic usage
pubnub.channel(f'{channel1}')
Create channel groups
This method returns a local PubNubChannelGroup
entity.
pubnub.channel_group(String)
Parameter | Type | Required | Description |
---|---|---|---|
channel_group | String | Yes | The name of the channel group to create a subscription of. |
Basic usage
pubnub.channel_group("channelGroupName")
Create channel metadata
This method returns a local PubNubChannelMetadata
entity.
pubnub.channel_metadata(String)
Parameter | Type | Required | Description |
---|---|---|---|
channel_metadata | String | Yes | The String identifier of the channel metadata object to create a subscription of. |
Basic usage
pubnub.channel_metadata("channelMetadata")
Create user metadata
This method returns a local PubNubUserMetadata
entity.
pubnub.user_metadata(String)
Parameter | Type | Required | Description |
---|---|---|---|
user_metadata | String | Yes | The String identifier of the user metadata object to create a subscription of. |
Basic usage
pubnub.userMetadata("user_metadata")
Event listeners
Messages and events are received in your app using a listener. This listener allows a single point to receive all messages, signals, and events.
You can attach listeners to the instances of Subscription
, SubscriptionSet
, and, in the case of the connection status, the PubNub client.
Add listeners
You can implement multiple listeners or register an event-specific listener that receives only a selected type, like message
or file
.
Method(s)
# Add event-specific listeners
# using closure for reusable listener
def on_message(listener):
def message_callback(message):
print(f"\033[94mMessage received on: {listener}: \n{message.message}\033[0m\n")
return message_callback
# without closure
def on_message_action(message_action):
print(f"\033[5mMessageAction received: \n{message_action.value}\033[0m\n")
def on_presence(listener):
def presence_callback(presence):
print(f"\033[0;32mPresence received on: {listener}: \t{presence.uuid} {presence.event}s "
show all 77 linesBasic usage
subscription = pubnub.channel(f'{channel1}').subscription()
def on_message(listener):
def message_callback(message):
print(f"\033[94mMessage received on: {listener}: \n{message.message}\033[0m\n")
return message_callback
def on_message_action(message_action):
print(f"\033[5mMessageAction received: \n{message_action.value}\033[0m\n")
subscription.on_message = on_message('message_listener')
subscription.on_message_action = on_message_action
subscription.subscribe()
show all 20 linesAdd connection status listener
The PubNub client has a listener dedicated to handling connection status updates.
Client scope
This listener is only available on the PubNub object.
Method(s)
pubnub.add_listener()
Basic usage
class PrintListener(SubscribeListener):
def status(self, pubnub, status):
print(f'Status:\n{status.__dict__}')
def message(self, pubnub, message):
pass
def presence(self, pubnub, presence):
pass
listener = PrintListener()
pubnub.add_listener(listener)
Returns
The subscription status. For information about available statuses, refer to SDK statuses.
Unsubscribe
Stop receiving real-time updates from a Subscription
or a SubscriptionSet
.
Method(s)
subscription.unsubscribe()
subscription_set.unsubscribe()
Basic Usage
channel = pubnub.channel(f'{channel}')
t1_subscription = channel.subscription()
t1_subscription.subscribe()
subscription_set1 = pubnub.subscription_set(channels=['channel1', 'channel2'])
subscription_set.subscribe()
t1_subscription1.unsubscribe()
subscription_set.unsubscribe()
Returns
None
Unsubscribe All
Stop receiving real-time updates from all data streams and remove the entities associated with them.
Client scope
This method is only available on the PubNub object.
Method(s)
pubnub.unsubscribe_all()
Basic Usage
channel = pubnub.channel(f'{channel}')
t1_subscription = channel.subscription()
t1_subscription.subscribe()
subscription_set1 = pubnub.subscription_set(channels=['channel1', 'channel2'])
subscription_set.subscribe()
t1_subscription1.unsubscribe()
subscription_set.unsubscribe()
pubnub.unsubscribe_all()
Returns
None
Subscribe (deprecated)
Deprecated
This method is deprecated. Use Subscribe instead.
Receive messages
Your app receives messages and events via event listeners. The event listener is a single point through which your app receives all the messages, signals, and events that are sent in any channel you are subscribed to.
For more information about adding a listener, refer to the Event Listeners section.
Description
This function causes the client to create an open TCP socket to the PubNub Real-Time Network and begin listening for messages on a specified channel
. To subscribe to a channel
the client must send the appropriate subscribe_key
at initialization.
By default a newly subscribed client will only receive messages published to the channel after the subscribe()
call completes.
If a client gets disconnected from a channel, it can automatically attempt to reconnect to that channel
and retrieve any available messages that were missed during that period. This can be achieved by setting setReconnectionPolicy
to PNReconnectionPolicy.LINEAR
, when initializing the client.
Unsubscribing from all channels
Unsubscribing from all channels, and then subscribing to a new channel Y is not the same as subscribing to channel Y and then unsubscribing from the previously-subscribed channel(s). Unsubscribing from all channels resets the last-received timetoken
and thus, there could be some gaps in the subscription that may lead to message loss.
Method(s)
To Subscribe to a channel
you can use the following method(s) in the Python SDK:
pubnub.subscribe() \
.channels(String|List|Tuple) \
.channel_groups(String|List|Tuple) \
.with_timetoken(Int) \
.with_presence() \
.execute()
Parameter | Type | Required | Description |
---|---|---|---|
channels | String | List | Tuple | Optional | Subscribe to channels , Either channel or channel_group is required. |
channel_groups | String | List | Tuple | Optional | Subscribe to channel_groups , Either channel or channel_group is required. |
timetoken | Int | Optional | Pass a timetoken . |
with_presence | Command | Optional | Also subscribe to related presence information. |
Basic Usage
Subscribe to a channel:
pubnub.subscribe() \
.channels('my_channel') \
.execute()
Event listeners
The response of the call is handled by adding a Listener. Please see the Listeners section for more details. Listeners should be added before calling the method.
Returns
PNMessageResult
PNMessageResult
is returned in the Listeners
The subscribe()
operation returns a PNStatus
for messages which contains the following fields:
Field | Type | Description |
---|---|---|
category | PNStatusCategory | Details of StatusCategory are here |
is_error | Boolean | This is True if an error occurred in the execution of the operation. |
error_data | PNErrorData | Error data of the exception (if Error is True ). |
status_code | int | Status code of the execution. |
The subscribe()
operation returns a PNMessageResult
for messages which contains the following fields:
Field | Type | Description |
---|---|---|
message | Object | The message sent on channel . |
subscription | String | The channel group or wildcard subscription match (if exists). |
channel | String | The channel for which the message belongs. |
timetoken | Int | Timetoken for the message. |
user_metadata | Dictionary | User metadata . |
The subscribe()
operation returns a PNPresenceEventResult
from presence which contains the following operations:
Field | Type | Description |
---|---|---|
event | String | Events like join , leave , timeout , state-change . |
uuid | String | uuid for event. |
timestamp | Int | timestamp for event. |
occupancy | Int | Current occupancy . |
subscription | String | The channel group or wildcard subscription match (if exists). |
channel | String | The channel for which the message belongs. |
timetoken | Int | timetoken of the message. |
user_metadata | Dictionary | User metadata . |
The subscribe()
operation returns a PNSignalResult
for signals which contains the following operations:
Field | Type | Description |
---|---|---|
timetoken | Int | An int representation of the timetoken when Signal was sent. |
channel | String | The channel on which Signal occurred. |
publisher | String | ID of the sender. |
message | Object | The payload. |
Other Examples
Basic subscribe with logging
import logging
import pubnub
from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub, SubscribeListener
pubnub.set_stream_logger('pubnub', logging.DEBUG)
pnconfig = PNConfiguration()
pnconfig.subscribe_key = 'demo'
pnconfig.publish_key = 'demo'
pubnub = PubNub(pnconfig)
show all 17 linesSubscribing to multiple channels
It's possible to subscribe to more than one channel using the Multiplexing feature. The example shows how to do that using an array to specify the channel names.
Alternative subscription methods
You can also use Wildcard Subscribe and Channel Groups to subscribe to multiple channels at a time. To use these features, the Stream Controller add-on must be enabled on your keyset in the Admin Portal.
pubnub.subscribe() \
.channels(["my_channel1", "my_channel2"]) \
.execute()
Subscribing to a Presence channel
Requires Presence add-on
This method requires that the Presence add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.
For any given channel there is an associated Presence channel. You can subscribe directly to the channel by appending -pnpres
to the channel name. For example the channel named my_channel
would have the presence channel named my_channel-pnpres
.
pubnub.subscribe()\
.channels("my_channel")\
.with_presence()\
.execute()
Sample Responses
Join Event
if envelope.event == 'join':
envelope.uuid # 175c2c67-b2a9-470d-8f4b-1db94f90e39e
envelope.timestamp # 1345546797
envelope.occupancy # 2
Leave Event
{
"action" : "leave",
"timestamp" : 1345549797,
"uuid" : "175c2c67-b2a9-470d-8f4b-1db94f90e39e",
"occupancy" : 1
}
Timeout Event
if envelope.event == 'timeout':
envelope.uuid # 175c2c67-b2a9-470d-8f4b-1db94f90e39e
envelope.timestamp # 1345546797
envelope.occupancy # 0
Custom Presence Event (State Change)
if envelope.event == 'state-change':
envelope.uuid # 76c2c571-9a2b-d074-b4f8-e93e09f49bd
envelope.timestamp # 1345546797
envelope.user_metadata # {'is_typing': True}
Interval Event
{
"action":"interval",
"timestamp":1474396578,
"occupancy":2
}
When a channel is in interval mode with presence_deltas
pnconfig
flag enabled, the interval message may also include the following fields which contain an array of changed UUIDs since the last interval message.
- joined
- left
- timedout
For example, this interval message indicates there were 2 new UUIDs that joined and 1 timed out UUID since the last interval:
{
"action" : "interval",
"occupancy" : <# users in channel>,
"timestamp" : <unix timestamp>,
"joined" : ["uuid2", "uuid3"],
"timedout" : ["uuid1"]
}
If the full interval message is greater than 30KB
(since the max publish payload is ∼32KB
), none of the extra fields will be present. Instead there will be a here_now_refresh
boolean field set to True
. This indicates to the user that they should do a hereNow
request to get the complete list of users present in the channel.
{
"action" : "interval",
"occupancy" : <# users in channel>,
"timestamp" : <unix timestamp>,
"here_now_refresh" : True
}
Wildcard subscribe to channels
Requires Stream Controller add-on
This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal (with Enable Wildcard Subscribe checked). Read the support page on enabling add-on features on your keys.
Wildcard subscribes allow the client to subscribe to multiple channels using wildcard. For example, if you subscribe to a.*
you will get all messages for a.b
, a.c
, a.x
. The wildcarded *
portion refers to any portion of the channel string name after the dot (.)
.
pubnub.subscribe() \
.channels("foo.*") \
.execute()
Wildcard grants and revokes
Only one level (a.*
) of wildcarding is supported. If you grant on *
or a.b.*
, the grant will treat *
or a.b.*
as a single channel named either *
or a.b.*
. You can also revoke permissions from multiple channels using wildcards but only if you previously granted permissions using the same wildcards. Wildcard revokes, similarly to grants, only work one level deep, like a.*
.
Subscribing with State
Requires Presence add-on
This method requires that the Presence add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.
Required user_id
Always set the user_id
to uniquely identify the user or device that connects to PubNub. This user_id
should be persisted, and should remain unchanged for the lifetime of the user or the device. If you don't set the user_id
, you won't be able to connect to PubNub.
from pubnub.enums import PNStatusCategory
from pubnub.pubnub import SubscribeListener, PubNub
class MySubscribeListener(SubscribeListener):
def __init__(self):
if status.category == PNStatusCategory.PNConnectedCategory:
state = {
'field_a': 'awesome',
'field_b': 10
}
envelope = pubnub.set_state().channels('my_channel').\
channel_groups('awesome_channel_groups').state(state).sync()
else:
show all 32 linesSubscribe to a channel group
Requires Stream Controller add-on
This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.
pubnub.subscribe() \
.channel_groups("awesome_channel_group") \
.execute()
Subscribe to the presence channel of a channel group
note
This method requires both the Stream Controller and Presence add-ons are enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.
pubnub.subscribe() \
.channel_groups("awesome_channel_group") \
.with_presence() \
.execute()
Event Listeners
You can be notified of connectivity status, message and presence notifications via the listeners.
Listeners should be added before calling the method.
Add Listeners
from pubnub.callbacks import SubscribeCallback
from pubnub.enums import PNOperationType, PNStatusCategory
class MySubscribeCallback(SubscribeCallback):
def message(self, pubnub, message):
print("Message channel: %s" % message.channel)
print("Message subscription: %s" % message.subscription)
print("Message timetoken: %s" % message.timetoken)
print("Message payload: %s" % message.message)
print("Message publisher: %s" % message.publisher)
def presence(self, pubnub, presence):
# Can be join, leave, state-change, timeout, or interval
print("Presence event: %s" % presence.event)
show all 104 linesRemove Listeners
my_listener = MySubscribeCallback()
pubnub.add_listener(my_listener)
# some time later
pubnub.remove_listener(my_listener)
Handling Disconnects
from pubnub.callbacks import SubscribeCallback
from pubnub.enums import PNStatusCategory
class HandleDisconnectsCallback(SubscribeCallback):
def status(self, pubnub, status):
if status.category == PNStatusCategory.PNUnexpectedDisconnectCategory:
# internet got lost, do some magic and call reconnect when ready
pubnub.reconnect()
elif status.category == PNStatusCategory.PNTimeoutCategory:
# do some magic and call reconnect when ready
pubnub.reconnect()
else:
logger.debug(status)
def presence(self, pubnub, presence):
show all 26 linesListener status events
Category | Description |
---|---|
PNTimeoutCategory | Failure to establish a connection to PubNub due to a timeout. |
PNBadRequestCategory | The server responded with a bad response error because the request is malformed. |
PNNetworkIssuesCategory | A subscribe event experienced an exception when running. The SDK isn't able to reach PubNub servers. This may be due to many reasons, such as: the machine or device isn't connected to the internet; the internet connection has been lost; your internet service provider is having trouble; or, perhaps the SDK is behind a proxy. |
PNReconnectedCategory | The SDK was able to reconnect to PubNub. |
PNConnectedCategory | SDK subscribed with a new mix of channels. This is fired every time the channel or channel group mix changes. |
PNUnexpectedDisconnectCategory | Previously started subscribe loop did fail and at this moment client disconnected from real-time data channels. |
PNUnknownCategory | Returned when the subscriber gets a non-200 HTTP response code from the server. |
SubscribeListener
should not be used with high-performance sections of your app.
Unsubscribe (deprecated)
Deprecated
This method is deprecated. Use Unsubscribe instead.
When subscribed to a single channel, this function causes the client to issue a leave
from the channel
and close any open socket to the PubNub Network. For multiplexed channels, the specified channel
(s) will be removed and the socket remains open until there are no more channels remaining in the list.
Unsubscribing from all channels
Unsubscribing from all channels, and then subscribing to a new channel Y is not the same as subscribing to channel Y and then unsubscribing from the previously-subscribed channel(s). Unsubscribing from all channels resets the last-received timetoken
and thus, there could be some gaps in the subscription that may lead to message loss.
Method(s)
To Unsubscribe from a channel
you can use the following method(s) in the Python SDK:
pubnub.unsubscribe() \
.channels(String|List|Tuple) \
.channel_groups(String|List|Tuple) \
.execute()
Parameter | Type | Required | Description |
---|---|---|---|
channels | String | List | Tuple | Optional | Subscribe to channels , Either channel or channel_group is required. |
channel_groups | String | List | Tuple | Optional | Subscribe to channel_groups , Either channel or channel_group is required |
Basic Usage
Unsubscribe from a channel:
pubnub.unsubscribe() \
.channels("my_channel") \
.execute()
Event listeners
The response of the call is handled by adding a Listener. Please see the Listeners section for more details. Listeners should be added before calling the method.
Response
The output below demonstrates the response to a successful call:
if envelope.event == 'leave':
envelope.uuid # 175c2c67-b2a9-470d-8f4b-1db94f90e39e
envelope.timestamp # 1345546797
envelope.occupancy # 2
Other Examples
Unsubscribing from multiple channels
Requires Stream Controller add-on
This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.
pubnub.unsubscribe() \
.channels(["my_channel1", "my_channel2"]) \
.execute()
Example Response
{
"action" : "leave"
}
Unsubscribe from a channel group
pubnub.unsubscribe() \
.channels_groups(["my_group1", "my_group2") \
.execute()
{
"action": "leave"
}
Unsubscribe All (deprecated)
Deprecated
This method is deprecated. Use Unsubscribe All instead.
Unsubscribe from all channels and all channel groups.
Method(s)
pubnub.unsubscribe_all()
Basic Usage
pubnub.unsubscribe_all()
Returns
None