Pusher REST Python library

status: Alpha

This is the new python library that will replace the "pusher" module once it becomes stable enough.

In order to use this library, you need to have an account on http://pusher.com. After registering, you will need the application credentials for your app.

Features

• Python 2.6, 2.7 and 3.3 support
• Adapters for various http libraries like requests, aiohttp and tornado
• WebHook validation
• Signature generation for socket subscriptions

Installation

You can install this module using your package management method or choice, normally easy_install or pip. For example:

pip install pusher-rest

Note: When 1.0 is reached pusher-rest will no longer be updated. Instead pusher should be used

Getting started

The minimum configuration required to use the Pusher object are the three constructor arguments which identify your Pusher app. You can find them by going to "API Keys" on your app at https://app.pusher.com.

from pusher import Pusher
pusher = Pusher(app_id=u'4', key=u'key', secret=u'secret')

You can then trigger events to channels. Channel and event names may only contain alphanumeric characters, - and _:

pusher.trigger(u'a_channel', u'an_event', {u'some': u'data'})

Configuration

from pusher import Pusher, Config
pusher = Pusher(app_id, key, secret, config=None, backend=None)

Argument	Description
app_id String	Required The Pusher application ID
key String	Required The Pusher application key
secret String	Required The Pusher application secret token
config Config	Default:None Additional Configuration via a Config object
config.ssl bool	Default:False Use HTTPS
config.host String	Default:None The host to connect to
config.port int	Default:None Which port to connect to
config.cluster String	Default:None Convention for other clusters than the main Pusher-one. Eg: 'eu' will resolve to the api-eu.pusherapp.com host
backend Object	an object that responds to the send_request(request) method. If none is provided, a python.sync.SynchronousBackend instance is created.

Example

from pusher import Pusher, Config
pusher = Pusher(app_id=u'4', key=u'key', secret=u'secret', Config(ssl=True, cluster=u'eu'))

Triggering Events

To trigger an event on one or more channels, use the trigger method on the Pusher object.

Pusher::trigger

Argument	Description
channels String or Collection	Required The name or list of names of the channel you wish to trigger events on
event String	Required The name of the event you wish to trigger.
data JSONable data	Required The event's payload
socket_id String	Default:None The socket_id of the connection you wish to exclude from receiving the event. You can read more here.

Return Values	Description
buffered_events Dict	A parsed response that includes the event_id for each event published to a channel. See example.

Example

This call will trigger to 'a_channel' and 'another_channel', and exclude the recipient with socket_id "1234.12".

pusher.trigger([u'a_channel', u'another_channel'], u'an_event', {u'some': u'data'}, "1234.12")

Event Buffer

Version 1.0.0 of the library introduced support for event buffering. The purpose of this functionality is to ensure that events that are triggered during whilst a client is offline for a short period of time will still be delivered upon reconnection.

Note: this requires your Pusher application to be on a cluster that has the Event Buffer capability.

As part of this the trigger function now returns a set of event_id values for each event triggered on a channel. These can then be used by the client to tell the Pusher service the last event it has received. If additional events have been triggered after that event ID the service has the opportunity to provide the client with those IDs.

Example

events = pusher.trigger([u'a_channel', u'another_channel'], u'an_event', {u'some': u'data'}, "1234.12")

#=> {'event_ids': {'another_channel': 'eudhq17zrhfbwc', 'a_channel': 'eudhq17zrhfbtn'}}

Querying Application State

Getting Information For All Channels

Pusher::channels_info

Argument	Description
prefix_filter String	Default: None Filter the channels returned by their prefix
attributes Collection	Default: [] A collection of attributes which should be returned for each channel. If empty, an empty dictionary of attributes will be returned for each channel. Available attributes: "user_count".

Return Values	Description
channels Dict	A parsed response from the HTTP API. See example.

Example

channels = pusher.channels_info(u"presence-", [u'user_count'])

#=> {u'channels': {u'presence-chatroom': {u'user_count': 2}, u'presence-notifications': {u'user_count': 1}}}

Getting Information For A Specific Channel

Pusher::channel_info

Argument	Description
channel String	Required The name of the channel you wish to query
attributes Collection	Default: [] A collection of attributes to be returned for the channel. Available attributes: "user_count" : Number of distinct users currently subscribed. Applicable only to presence channels. "subscription_count": [BETA]: Number of connections currently subscribed to the channel. Please contact us to enable this feature.

Return Values	Description
channel Dict	A parsed response from the HTTP API. See example.

Example

channel = pusher.channel_info(u'presence-chatroom', [u"user_count"])
#=> {u'user_count': 42, u'occupied': True}

Getting User Information For A Presence Channel

Pusher::users_info

Argument	Description
channel String	Required The name of the presence channel you wish to query

Return Values	Description
users Dict	A parsed response from the HTTP API. See example.

Example

pusher.users_info(u'presence-chatroom')
#=> {u'users': [{u'id': u'1035'}, {u'id': u'4821'}]}

Authenticating Channel Subscription

Pusher::authenticate

In order for users to subscribe to a private- or presence-channel, they must be authenticated by your server.

The client will make a POST request to an endpoint (either "/pusher/auth" or any which you specify) with a body consisting of the channel's name and socket_id.

Using your Pusher instance, with which you initialized Pusher, you can generate an authentication signature. Having responded to the request with this signature, the subscription will be authenticated.

Argument	Description
channel String	Required The name of the channel, sent to you in the POST request
socket_id String	Required The channel's socket_id, also sent to you in the POST request
custom_data Dict	Required for presence channels This will be a dictionary containing the data you want associated with a member of a presence channel. A "user_id" key is required, and you can optionally pass in a "user_info" key. See the example below.

Return Values	Description
response Dict	A dictionary to send as a response to the authentication request.

Example

Private Channels

auth = pusher.authenticate_subscription(

  channel=u"private-channel",

  socket_id=u"1234.12"
)
# return `auth` as a response

Presence Channels

auth = pusher.authenticate_subscription(

  channel=u"presence-channel",

  socket_id=u"1234.12",

  custom_data={
    u'user_id': u'1',
    u'user_info': {
      u'twitter': '@pusher'
    }
  }
)
# return `auth` as a response

Receiving Webhooks

If you have webhooks set up to POST a payload to a specified endpoint, you may wish to validate that these are actually from Pusher. The Pusher object achieves this by checking the authentication signature in the request body using your application credentials.

Pusher::validate_webhook

Argument	Description
key String	Required Pass in the value sent in the request headers under the key "X-PUSHER-KEY". The method will check this matches your app key.
signature String	Required This is the value in the request headers under the key "X-PUSHER-SIGNATURE". The method will verify that this is the result of signing the request body against your app secret.
body String	Required The JSON string of the request body received.

Return Values	Description
body_data Dict	If validation was successful, the return value will be the parsed payload. Otherwise, it will be None.

Example

webhook = pusher.validate_webhook(

  key="key_sent_in_header",

  signature="signature_sent_in_header",

  body="{ \"time_ms\": 1327078148132  \"events\": [ { \"name\": \"event_name\", \"some\": \"data\" }  ]}"
)

print webhook["events"]

Running the tests

To run the tests run python setup.py test

License

Copyright (c) 2015 Pusher Ltd. See LICENSE for details.