Configuration API for Python SDK

Python complete API reference for building real-time applications on PubNub, including basic usage and sample code.

Configuration​

PNConfiguration instance is storage for user-provided information which describe further PubNub client behavior. Configuration instance contain additional set of properties which allow to perform precise PubNub client configuration.

Method(s)​

To create configuration instance you can use the following function in the Python SDK:

pnconfig = PNConfiguration()
PropertiesTypeRequiredDefaultDescription
subscribe_key
String
Yes
subscribe_key from Admin Portal.
publish_key
String
Optional
None
publish_key from Admin Portal (only required if publishing).
secret_key
String
Optional
None
secret_key (only required for modifying/revealing access permissions)
user_id
String
Yes
user_id to use. You should set a unique user_id to identify the user or the device that connects to PubNub.

It's a UTF-8 encoded string of up to 92 alphanumeric characters.

If you don't set the user_id, you won't be able to connect to PubNub.
auth_key
String
Optional
None
If Access Manager is utilized, client will use this authKey in all restricted requests.
ssl
Boolean
Optional
True
Use SSL.
connect_timeout
Int
Optional
5
How long to wait before giving up connection to client.The value is in seconds.
subscribe_request_timeout
Int
Optional
310
How long to keep the subscribe loop running before disconnect. The value is in seconds.
non_subscribe_request_timeout
Int
Optional
10
On non subscribe operations, how long to wait for server response. The value is in seconds.
filter_expression
String
Optional
None
Feature to subscribe with a custom filter expression.
heartbeat_notification_options
PNHeartbeatNotificationOptions
Optional
PNHeartbeatNotificationOptions.FAILURES
Heartbeat notifications, by default, the SDK will alert on failed heartbeats (equivalent to: PNHeartbeatNotificationOptions.FAILURES).
Other options such as all heartbeats (PNHeartbeatNotificationOptions.ALL) or no heartbeats (PNHeartbeatNotificationOptions.NONE) are supported.
reconnect_policy
PNReconnectionPolicy
Optional
PNReconnectionPolicy.EXPONENTIAL (subscribe only)
Custom reconnection configuration parameters. PNReconnectionPolicy is the type of policy to be used.

Available values:
  • PNReconnectionPolicy.NONE
  • PNReconnectionPolicy.LINEAR (see maximum_reconnection_retries and reconnection_interval below)
  • PNReconnectionPolicy.EXPONENTIAL


For more information, refer to SDK connection lifecycle.
maximum_reconnection_retries
int
Optional
10
Number of times a request can be retried. Only applicable to PNReconnectionPolicy.LINEAR.
reconnection_interval
float
Optional
2.0
The delay in seconds between failed retry attempts. Only applicable to PNReconnectionPolicy.LINEAR.
suppress_leave_events
Boolean
Optional
False
If True, the client doesn't send presence leave events during the unsubscribe process.
enable_subscribe
Boolean
Optional
True
You can disable the subscribe loop if you don't need to perform subscribe operations. By default, subscribe loop is enabled and extra threads/loops are started. They should be explicitly stopped by pubnub.stop() method invocation.
daemon
Boolean
Optional
False
When set to True, spawned thread won't keep the application running after SIGTERM. (ctrl-c from command line, for example)
disable_token_manager
Boolean
Optional
False
When set to True, the Token Manager System (TMS) will be disabled. Even if there are applicable tokens, no requests will be authorized.
cipher_mode
AES.MODE_CBC or AES.MODE_GCM
Optional
AES.MODE_CBC
The cipher method to be used for message encryption for the legacy crypto module. By default, all PubNub SDKs use CBC.

⚠️Warning!
If you set the Python SDK's cipher_mode to GCM, ensure that all other clients can decode the message.
fallback_cipher_mode
AES.MODE_CBC or AES.MODE_GCM
Optional
None
The secondary cipher method used for message decryption for the legacy crypto module. It is used if the method set in the cipher_mode parameter fails to decrypt the messages.
cipher_key
String
Optional
None
If cipher_key is passed, all communications to/from PubNub will be encrypted.
use_random_initialization_vector
Boolean
Optional
True
When True the initialization vector (IV) is random for all requests (not just for file upload). When False the IV is hard-coded for all requests except for file upload.
crypto_module
PubNubCryptoModule
Optional
None
The cryptography module used for encryption and decryption of messages and files. Takes the config (PNConfiguration instance with cipher_key and use_random_initialization_vector) parameter as argument.

For more information, refer to the crypto_module section.
uuid
String
Yes
This parameter is deprecated, use user_id instead. UUID to use. You should set a unique UUID to identify the user or the device that connects to PubNub.
If you don't set the UUID, you won't be able to connect to PubNub.
Disabling random initialization vector

Disable random initialization vector (IV) only for backward compatibility (<5.1.0) with existing applications. Never disable random IV on new applications.

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Working with cipher mode

example

crypto_module​

crypto_module provides encrypt/decrypt functionality for messages and files. From the 7.2.0 release on, you can configure how the actual encryption/decryption algorithms work.

Each PubNub SDK is bundled with two ways of encryption: the legacy encryption with 128-bit cipher key entropy and the recommended 256-bit AES-CBC encryption. For more general information on how encryption works, refer to the Message Encryption and File Encryption sections.

If you do not explicitly set the crypto_module in your app and have the cipher_key and use_random_initialization_vector params set in PubNub config, the client defaults to using the legacy encryption.

Legacy encryption with 128-bit cipher key entropy

You don't have to change your encryption configuration if you want to keep using the legacy encryption. If you want to use the recommended 256-bit AES-CBC encryption, you must explicitly set that in PubNub config.

crypto_module configuration​

To configure the crypto_module to encrypt all messages/files, you can use the following methods in the Python SDK:

#  encrypts using 256-bit AES-CBC cipher (recommended)
#  decrypts data encrypted with the legacy (AES and GCM) and the 256-bit AES-CBC ciphers
config = PNConfiguration()
...
# all necessary config options
config.cipher_key = "my_cipher_key"
config.cipher_mode = AES.MODE_GCM # optional, used for the legacy module only
config.fallback_cipher_mode = AES.MODE_CBC # optional, used for the legacy module only
config.crypto_module = AesCbcCryptoModule(config)
pubnub = PubNub(config)

#  encrypts with 128-bit cipher key entropy (legacy) with GCM
#  decrypts data encrypted with the legacy (AES and GCM) and the 256-bit AES-CBC ciphers
config = PNConfiguration()
...
show all 33 lines

Your client can decrypt content encrypted using either of the modules. This way, you can interact with historical messages or messages sent from older clients while encoding new messages using the more secure 256-bit AES-CBC cipher.

Older SDK versions

Apps built using the SDK versions lower than 7.2.0 will not be able to decrypt data encrypted using the 256-bit AES-CBC cipher. Make sure to update your clients or encrypt data using the legacy algorithm.

Basic Usage​

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.pnconfiguration import PNConfiguration
from pubnub.enums import PNHeartbeatNotificationOptions

pn_configuration = PNConfiguration()
# subscribe_key from Admin Portal
pn_configuration.subscribe_key = "my_subscribe_key"
# publish_key from Admin Portal (only required if publishing)
pn_configuration.publish_key = "my_publish_key"
# secret_key (only required for modifying/revealing access permissions)
pn_configuration.secret_key = "my_secret_key"
# if cipher_key is passed, all communicatons to/from pubnub will be encrypted
pn_configuration.cipher_key = "my_cipher_key"
# the cryptography module used for encryption and decryption
pn_configuration.crypto_module = AesCbcCryptoModule(pn_configuration)
# user ID to be used as a device identifier, won't connect if not set
show all 32 lines

Initialization​

Add PubNub to your project using one of the procedures defined in the Getting Started guide.

Description​

This function is used for initializing the PubNub Client API context. This function must be called before attempting to utilize any API functionality in order to establish account level credentials such as publish_key and subscribe_key.

Method(s)​

To Initialize PubNub you can use the following method(s) in the Python SDK:

pubnub = PubNub(pn_configuration, custom_request_handler)
* required
ParameterDescription
pn_configuration *
Default:
n/a
The configuration object. For more details, refer to Configuration.
custom_request_handler
Type: subclass of BaseRequestHandler
Default:
HttpxRequestHandler
The optional custom HTTP request handler. For more information, refer to Custom request handler.

Custom request handler​

The custom_request_handler optional configuration option allows you to select the library for sending HTTP requests.

If you don't specify this parameter, the Python SDK first checks the value of the PUBNUB_REQUEST_HANDLER environment variable. If you don't set the variables or their value is not a subclass of BaseRequestHandler, the PubNub Python SDK defaults to HttpxRequestHandler.

ClassDescription
HttpxRequestHandler
Python SDK synchronous requests handler based on the httpx HTTP library.
RequestsRequestHandler
Python SDK synchronous requests handler based on the requests HTTP library.

Basic Usage​

Initialize the PubNub client API​

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.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

pnconfig = PNConfiguration()
pnconfig.subscribe_key = "my_subkey"
pnconfig.publish_key = "my_pubkey"
pnconfig.ssl = True
pnconfig.user_id = "my_custom_user_id"
pubnub = PubNub(pnconfig)

Returns​

It returns the PubNub instance for invoking PubNub APIs like publish(), subscribe(), history(), here_now(), etc.

Other Examples​

Use a custom request handler​

You can set a custom request handler by specifying one of the available request handlers during the initialization of the PubNub client.

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.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub
from pubnub.request_handlers.requests_handler import RequestsRequestHandler

pnconfig = PNConfiguration()
pnconfig.subscribe_key = "my_subkey"
pnconfig.publish_key = "my_pubkey"
pnconfig.user_id = "my_custom_user_id"

pubnub = PubNub(pnconfig, custom_request_handler=RequestsRequestHandler)

Initialize a non-secure client​

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.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

pnconfig = PNConfiguration()
pnconfig.subscribe_key = "my_subkey"
pnconfig.publish_key = "my_pubkey"
pnconfig.ssl = False
pnconfig.user_id = "my_custom_user_id"
pubnub = PubNub(pnconfig)

Initialization for a Read-Only client​

In the case where a client will only read messages and never publish to a channel, you can simply omit the publish_key when initializing the client:

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.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

pnconfig = PNConfiguration()
pnconfig.subscribe_key = "my_subkey"

pubnub = PubNub(pnconfig)

Use a custom User ID​

Set a custom user_id to identify your users.

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.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

pnconfig = PNConfiguration()

pnconfig.subscribe_key = 'mySubscribeKey'
pnconfig.publish_key = 'myPublishKey'
pnconfig.user_id = "my_custom_user_id"

pubnub = PubNub(pnconfig)

Initializing with SSL Enabled​

This examples demonstrates how to enable PubNub Transport Layer Encryption with SSL. Just initialize the client with ssl set to True. The hard work is done, now the PubNub API takes care of the rest. Just subscribe and publish as usual and you are good to go.

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.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

pnconfig = PNConfiguration()
pnconfig.subscribe_key = "my_subkey"
pnconfig.publish_key = "my_pubkey"
pnconfig.ssl = True
pnconfig.user_id = "my_custom_user_id"
pubnub = PubNub(pnconfig)

Initializing with Access Manager​

Requires Access Manager add-on

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

Secure your secret_key

Anyone with the secret_key can grant and revoke permissions to your app. Never let your secret_key be discovered, and to only exchange it / deliver it securely. Only use the secret_key on secure server-side platforms.

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.

For applications that will administer Access Manager permissions, the API is initialized with the secret_key as in the following example:

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.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

pnconfig = PNConfiguration()
pnconfig.subscribe_key = "my_subkey"
pnconfig.publish_key = "my_pubkey"
pnconfig.secret_key = "my_secretkey"
pnconfig.user_id = "my_custom_user_id"
pnconfig.ssl = True

pubnub = PubNub(pnconfig)

Now that the pubnub object is instantiated the client will be able to access the Access Manager functions. The pubnub object will use the secret_key to sign all Access Manager messages to the PubNub Network.

Event Listeners​

PubNub SDKs provide several sources for real-time updates:

  • The PubNub client can receive updates from all subscriptions: all channels, channel groups, channel metadata, and users.
  • The Subscription object can receive updates only for the particular object for which it was created: channel, channel group, channel metadata, or user.
  • The SubscriptionsSet object can receive updates for all objects for which a list of subscription objects was created.

To facilitate working with those real-time update sources, PubNub SDKs use local representations of server entities that allow you to subscribe and add handlers on a per-entity basis. For more information, refer to Publish & Subscribe.

Filter Expression​

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.

Stream filtering allows a subscriber to apply a filter to only receive messages that satisfy the conditions of the filter. The message filter is set by the subscribing client(s) but it is applied on the server side thus preventing unwanted messages (those that do not meet the conditions of the filter) from reaching the subscriber.

To set or get message filters, you can use the following methods. To learn more about filtering, refer to the Publish Messages documentation.

Method(s)​

Set Filter Expression

The property accepts a string.

Get Filter Expression

The property returns a string.

Basic Usage​

Set Filter Expression​

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.pnconfiguration import PNConfiguration

pnconfig = PNConfiguration()
pnconfig.filter_expression = "such=wow"

Get Filter Expression​

filter = pnconfig.filter_expression
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