PubNub Python-Asyncio SDK 9.1.0

Get Code: pip​

The simplest way to get started is to install PubNub Python SDK via pip:​

pip install pubnub

Get Code: git​

git clone https://github.com/pubnub/python

Get Code: Source​

Hello World​

Add PubNub to your project using one of the procedures defined above.

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.

import asyncio
import os
import time

from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub, SubscribeListener


# this will print out the subscription status to console
class Listener(SubscribeListener):
    def status(self, pubnub, status):
        print(f'Status: \n{status.category.name}')


# here we create configuration for our pubnub instance
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Builders​

There are two ways to invoke callbacks in PubNub Python SDK for asyncio:

  • Using result(). The builder returns a future that yields an only result, no state available on success call. Exceptions in this builder are raised explicitly. status field of an error is populated with an associated status object.

    try:
        result = await pubnub.publish().message('hey').channel('blah').result()
        print(result)
    except PubNubException as e:
        print("PubNubException: %s" % e)
        print("category id: #%d" % e.status.category)
        print("operation id: #%d" % e.status.operation)
        _handle_error(e)
    except Exception as e:
        print("Error: %s" % e)
        _handle_error(e)

  • Using future(). The builder returns a future that yields a message envelope that wraps both a result (the same as in result() call) and a state object. Exception, if any, will not be raised explicitly and you should check for it using e.is_error() helper. To access original exception value use e.value() method.

    e = await pubnub.publish().message('hey').channel('blah').future()

    if e.is_error():
        print("Error: %s" % e)
        print("category id: #%d" % e.status.category)
        print("operation id: #%d" % e.status.operation)
        _handle_error(e)
    else:
        print(e.result)

Copy and paste examples​

In addition to the Hello World sample code, we also provide some copy and paste snippets of common API functions:

Init​

Instantiate a new Pubnub instance. Only the subscribe_key is mandatory. Also include publish_key if you intend to publish from this instance, and the secret_key if you wish to perform Access Manager administrative operations from this Python-asyncio instance.

Protect your secret_key

For security reasons you should only include the secret-key on a highly secured server. The secret-key is only required for granting rights using our Access Manager.

When you init with secret_key, you get root permissions for the Access Manager. With this feature you don't have to grant access to your servers to access channel data. The servers get all access on all channels.

Initializing the client​

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.pnconfiguration import PNConfiguration
from pubnub.pubnub_asyncio import PubNubAsyncio

pnconfig = PNConfiguration()
pnconfig.subscribe_key = "my_subkey"
pnconfig.publish_key = "my_pubkey"
pnconfig.uuid = "my_custom_uuid"
pnconfig.ssl = False

pubnub = PubNubAsyncio(pnconfig)

Listeners​

import asyncio
import os
import time

from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub, SubscribeListener


# this will replace default SubscribeListener with thing that will print out messages to console
class Listener(SubscribeListener):
    def status(self, pubnub, status):
        print(f'Status: \n{status.category.name}')


# here we create configuration for our pubnub instance
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Time​

Call time() to verify the client connectivity to the origin:

envelope = await pubnub.time().future()
    print('current time: %d' % envelope.result)

Subscribe​

Subscribe (listen on) a channel:

channel = pubnub.channel('example')
subscription = pubnub.channel(channel).subscription()

subscription.subscribe()
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.

Publish​

Publish a message to a channel:

def publish_callback(task):
    exception = task.exception()

    if exception:
        envelope = task.result()
        # Handle PNPublishResult(envelope.result) and PNStatus (envelope.status)
        pass
    else:
        # Handle exception
        pass

asyncio.ensure_future(
    pubnub.publish().channel('such_channel').message(['hello', 'there']).future()
).add_done_callback(publish_callback)

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Publish and Subscribe Continuously​

import os
import asyncio

from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub_asyncio import PubNubAsyncio, SubscribeCallback
from pubnub.enums import PNStatusCategory

class MySubscribeCallback(SubscribeCallback):
    def status(self, pubnub, status):
        if status.category == PNStatusCategory.PNUnexpectedDisconnectCategory:
            print("Disconnected")
        elif status.category == PNStatusCategory.PNConnectedCategory:
            print("Connected")
        elif status.category == PNStatusCategory.PNReconnectedCategory:
            print("Reconnected")
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Here Now​

Get occupancy of who's here now on the channel by UUID:

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.

envelope = await pubnub.here_now().channels(['cool_channel1', 'cool_channel2']).include_uuids(True).future()

if envelope.status.is_error():
    # handle error
    pass

for channel_data in envelope.result.channels:
    print("---")
    print("channel: %s" % channel_data.channel_name)
    print("occupancy: %s" % channel_data.occupancy)

    print("occupants: %s" % channel_data.channel_name)
for occupant in channel_data.occupants:
    print("uuid: %s, state: %s" % (occupant.uuid, occupant.state))

Presence​

Subscribe to real-time Presence events, such as join, leave, and timeout, by UUID. Setting the presence attribute to a callback will subscribe to presents events on my_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.

pubnub.subscribe().channels("my_channel").with_presence().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.

History​

Retrieve published messages from archival storage:

Requires Message Persistence

This method requires that Message Persistence is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

envelope = await pubnub.history().channel('history_channel').count(100).future()
# handle messages stored at evelope.result.messages
# status is available as envelope.status

Unsubscribe​

Stop subscribing (listening) to a channel:

channel = pubnub.channel(f'{channel}')
t1_subscription = channel.subscription()
t1_subscription.subscribe()
channel2 = pubnub.channel("channelName2")

subscription_set1 = pubnub.subscription_set([channel1, channel2])
subscription_set.subscribe()


t1_subscription1.unsubscribe()
subscription_set.unsubscribe()
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.

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