PubNub Python-Asyncio SDK 7.3.2
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 under How to Get It.
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
from pubnub.callbacks import SubscribeCallback
from pubnub.enums import PNStatusCategory
from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub_asyncio import PubNubAsyncio
pnconfig = PNConfiguration()
pnconfig.subscribe_key = 'demo'
pnconfig.publish_key = 'demo'
pnconfig.uuid = "my_custom_uuid"
pubnub = PubNubAsyncio(pnconfig)
async def main():
show all 63 linesBuilders
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 inresult()
call) and a state objects. Exception, if any, will not be raised explicitly and you should check for it usinge.is_error()
helper. To access original exception value usee.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
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
Add Listeners
from pubnub.callbacks import SubscribeCallback
from pubnub.enums import PNOperationType, PNStatusCategory
class MySubscribeCallback(SubscribeCallback):
def status(self, pubnub, status):
# The status object returned is always related to subscribe but could contain
# information about subscribe, heartbeat, or errors
# use the operationType to switch on different options
if status.operation == PNOperationType.PNSubscribeOperation \
or status.operation == PNOperationType.PNUnsubscribeOperation:
if status.category == PNStatusCategory.PNConnectedCategory:
pass
# This is expected for a subscribe, this means there is no error or issue whatsoever
elif status.category == PNStatusCategory.PNReconnectedCategory:
show all 58 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 the PubNub Data Stream Network. 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. |
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:
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.
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)
show all 16 linesHere 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:
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.