This package lets you trigger events to your client and query the state of your channels. When used with a server, you can validate webhooks and authenticate private-
or presence-
channels.
In order to use this library, you need to have a free account on https://pusher.com. After registering, you will need the application credentials for your app.
- Python - supports Python versions 2.7, 3.6 and above
- Adapters for various http libraries like requests, urlfetch, aiohttp (requires Python >= 3.5.3) and tornado.
- WebHook validation
- Signature generation for socket subscriptions
- Installation
- Getting started
- Configuration
- Triggering Events
- Querying Application State
- Authenticating Channel Subscription
- Terminating User Connections
- End-to-end Encryption
- Receiving Webhooks
- Request Library Configuration
- Feature Support
- Running the tests
- License
You can install this module using your package management method or choice,
normally easy_install
or pip
. For example:
pip install pusher
Users on Python 2.x and older versions of pip may get a warning, due to pip compiling the optional pusher.aiohttp
module, which uses Python 3 syntax. However, as pusher.aiohttp
is not used by default, this does not affect the library's functionality. See our Github issue, as well as this issue from Gunicorn for more details.
On Linux, you must ensure that OpenSSL is installed, e.g. on Debian/Ubuntu:
$ sudo apt-get install build-essential libssl-dev libffi-dev
The minimum configuration required to use the Pusher
object are the three
constructor arguments which identify your Pusher Channels app. You can find them by
going to "API Keys" on your app at https://app.pusher.com.
import pusher
pusher_client = pusher.Pusher(app_id=u'4', key=u'key', secret=u'secret', cluster=u'cluster')
You can then trigger events to channels. Channel and event names may only
contain alphanumeric characters, -
and _
:
pusher_client.trigger(u'a_channel', u'an_event', {u'some': u'data'})
import pusher
pusher_client = pusher.Pusher(app_id, key, secret, cluster=u'cluster')
Argument | Description |
---|---|
app_id String |
Required The Pusher Channels application ID |
key String |
Required The Pusher Channels application key |
secret String |
Required The Pusher Channels application secret token |
cluster String |
Default:mt1 The pusher application cluster. Will be overwritten if host is set |
host String |
Default:None The host to connect to |
port int |
Default:None Which port to connect to |
ssl bool |
Default:True Use HTTPS |
String |
Default:None Deprecated, see encryption_master_key_base64 |
encryption_master_key_base64 String |
Default:None The encryption master key for End-to-end Encryption |
backend Object |
an object that responds to the send_request(request) method. If none is provided, a pusher.requests.RequestsBackend instance is created. |
json_encoder Object |
Default: None Custom JSON encoder. |
json_decoder Object |
Default: None Custom JSON decoder. |
The constructor will throw a TypeError
if it is called with parameters that don’t match the types listed above.
import pusher
pusher_client = pusher.Pusher(app_id=u'4', key=u'key', secret=u'secret', ssl=True, cluster=u'cluster')
To trigger an event on one or more channels, use the trigger
method on the Pusher
object.
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. |
Pusher::trigger
will throw a TypeError
if called with parameters of the wrong type; or a ValueError
if called on more than 100 channels, with an event name longer than 200 characters, or with more than 10240 characters of data (post JSON serialisation).
This call will trigger to 'a_channel'
and 'another_channel'
, and exclude the recipient with socket_id "1234.12"
.
pusher_client.trigger([u'a_channel', u'another_channel'], u'an_event', {u'some': u'data'}, "1234.12")
It's also possible to send distinct messages in batches to limit the overhead of HTTP headers. There is a current limit of 10 events per batch on our multi-tenant clusters.
Argument | Description |
---|---|
batch Array of Dict |
Required A list of events to trigger |
Events are a Dict
with keys:
Argument | Description |
---|---|
channel String |
Required The name of the channel to publish to. |
name 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 |
---|---|
Dict |
An empty dict on success |
Pusher::trigger_batch
will throw a TypeError
if the data parameter is not JSONable.
pusher_client.trigger_batch([
{ u'channel': u'a_channel', u'name': u'an_event', u'data': {u'some': u'data'}, u'socket_id': '1234.12'},
{ u'channel': u'a_channel', u'name': u'an_event', u'data': {u'some': u'other data'}}
])
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. |
Pusher::channels_info
will throw a TypeError
if prefix_filter
is not a String
.
channels = pusher_client.channels_info(u"presence-", [u'user_count'])
#=> {u'channels': {u'presence-chatroom': {u'user_count': 2}, u'presence-notifications': {u'user_count': 1}}}
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" : Number of connections currently subscribed to the channel. Enable this feature in your Pusher dashboard's App Settings. |
Return Values | Description |
---|---|
channel Dict |
A parsed response from the HTTP API. See example. |
Pusher::channel_info
will throw a ValueError
if channel
is not a valid channel.
channel = pusher_client.channel_info(u'presence-chatroom', [u"user_count"])
#=> {u'user_count': 42, u'occupied': True}
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. |
Pusher::users_info
will throw a ValueError
if channel
is not a valid channel.
pusher_client.users_info(u'presence-chatroom')
#=> {u'users': [{u'id': u'1035'}, {u'id': u'4821'}]}
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. |
Pusher::authenticate
will throw a ValueError
if the channel
or socket_id
that it’s called with are invalid.
auth = pusher_client.authenticate(
channel=u"private-channel",
socket_id=u"1234.12"
)
# return `auth` as a response
auth = pusher_client.authenticate(
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
TIn order to terminate a user's connections, the user must have been authenticated. Check the Server user authentication docs for the information on how to create a user authentication endpoint.
To terminate all connections established by a given user, you can use the terminate_user_connections
function:
pusher_client.terminate_user_connections(userId)
Please note, that it only terminates the user's active connections. This means, if nothing else is done, the user will be able to reconnect. For more information see: Terminating user connections docs.
This library supports end to end encryption of your private channels. This means that only you and your connected clients will be able to read your messages. Pusher cannot decrypt them. You can enable this feature by following these steps:
-
You should first set up Private channels. This involves creating an authentication endpoint on your server.
-
Next, generate a 32 byte master encryption key, base64 encode it and store it securely.
This is secret and you should never share this with anyone. Not even Pusher.
To generate a suitable key from a secure random source, you could use:
openssl rand -base64 32
-
Pass your master key to the SDK constructor
import pusher pusher_client = pusher.Pusher( app_id='yourappid', key='yourkey', secret='yoursecret', encryption_master_key_base64='<output from command above>', cluster='yourclustername', ssl=True ) pusher_client.trigger('private-encrypted-my-channel', 'my-event', { 'message': 'hello world' })
-
Channels where you wish to use end to end encryption must be prefixed with
private-encrypted-
. -
Subscribe to these channels in your client, and you're done! You can verify it is working by checking out the debug console on the https://dashboard.pusher.com/ and seeing the scrambled ciphertext.
Important note: This will not encrypt messages on channels that are not prefixed by private-encrypted-.
More info on End-to-end Encrypted Channels here.
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.
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 . |
Pusher::validate_webhook
will raise a TypeError
if it is called with any parameters of the wrong type.
webhook = pusher_client.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"]
Users can configure the library to use different backends to send calls to our API. The HTTP libraries we support are:
- Requests (
pusher.requests.RequestsBackend
). This is used by default. - Tornado (
pusher.tornado.TornadoBackend
). - AsyncIO (
pusher.aiohttp.AsyncIOBackend
). - Google App Engine (
pusher.gae.GAEBackend
).
Upon initializing a Pusher
instance, pass in any of these options to the backend
keyword argument.
GAE users are advised to use the pusher.gae.GAEBackend
backend to ensure compatability.
Feature | Supported |
---|---|
Trigger event on single channel | ✔ |
Trigger event on multiple channels | ✔ |
Excluding recipients from events | ✔ |
Authenticating private channels | ✔ |
Authenticating presence channels | ✔ |
Get the list of channels in an application | ✔ |
Get the state of a single channel | ✔ |
Get a list of users in a presence channel | ✔ |
WebHook validation | ✔ |
Terminate user connections | ✔ |
Heroku add-on support | ✔ |
Debugging & Logging | ✔ |
Cluster configuration | ✔ |
Timeouts | ✔ |
HTTPS | ✔ |
End-to-end Encryption | ✔ |
HTTP Proxy configuration | ✘ |
HTTP KeepAlive | ✘ |
These are helpers that have been implemented to to ensure interactions with the HTTP API only occur if they will not be rejected e.g. channel naming conventions.
Helper Functionality | Supported |
---|---|
Channel name validation | ✔ |
Limit to 100 channels per trigger | ✔ |
Limit event name length to 200 chars | ✔ |
To run the tests run python setup.py test
Copyright (c) 2015 Pusher Ltd. See LICENSE for details.