pyapns

A universal Apple Push Notification Service (APNS) provider.

Features:

• XML-RPC Based, works with any client in any language
• Native Python API with Django and Pylons support
• Native Ruby API with Rails/Rack support
• Scalable, fast and easy to distribute behind a proxy
• Based on Twisted
• Multi-application and dual environment support
• Simplified feedback interface

pyapns is an APNS provider that you install on your server and access through XML-RPC. To install you will need Python, Twisted and pyOpenSSL. It's also recommended to install python-epoll for best performance (if epoll is not available, like on Mac OS X, you may want to use another library, like py-kqueue). If you like easy_install try (it should take care of the dependancies for you):

$ sudo easy_install pyapns

pyapns is a service that runs persistently on your machine. To start it:

$ twistd -r epoll web --class=pyapns.server.APNSServer --port=7077

This will create a twistd.pid file in your current directory that can be used to kill the process. twistd is a launcher used for running network persistent network applications. It takes many more options that can be found by running man twistd or using a web man page.

To get started right away, use the included client:

$ python
>>> from pyapns import configure, provision, notify
>>> configure({'HOST': 'http://localhost:7077/'})
>>> provision('myapp', open('cert.pem').read(), 'sandbox')
>>> notify('myapp', 'hexlified_token_str', {'aps':{'alert': 'Hello!'}})

The Multi-Application Model

pyapns supports multiple applications. Before pyapns can send notifications, you must first provision the application with an Application ID, the environment (either 'sandbox' or 'production') and the certificate file. The provision method takes 4 arguments, app_id, path_to_cert_or_cert, environment and timeout. A connection is kept alive for each application provisioned for the fastest service possible. The application ID is an arbitrary identifier and is not used in communication with the APNS servers.

When a connection can not be made within the specified timeout a timeout error will be thrown by the server. This usually indicates that the wrong [type of] certification file is being used, a blocked port or the wrong environment.

Attempts to provision the same application id multiple times are ignored.

Sending Notifications

Calling notify will send the message immediately if a connection is already established. The first notification may be delayed a second while the server connects. notify takes app_id, token_or_token_list and notification_or_notification_list. Multiple notifications can be batched for better performance by using paired arrays of token/notifications. When performing batched notifications, the token and notification arrays must be exactly the same length.

The full notification dictionary must be included as the notification:

{'aps': {
    'sound': 'flynn.caf',
    'badge': 0,
    'message': 'Hello from pyapns :)'
  }
} # etc...

Retrieving Inactive Tokens

Call feedback with the app_id. A list of tuples will be retrieved from the APNS server that it deems inactive. These are returned as a list of 2-element lists with a Datetime object and the token string.

XML-RPC Methods

These methods can be called on the server you started the server on. Be sure you are not including /RPC2 in the URL.

provision

  Arguments
      app_id        String            the application id for the provided
                                      certification
      cert          String            a path to a .pem file or the a
                                      string with the entie file
      environment   String            the APNS server to use - either
                                      'production' or 'sandbox'
      timeout       Integer           timeout for connection attempts to
                                      the APS servers
  Returns
      None

notify

  Arguments
      app_id        String            the application id to send the
                                      message to
      tokens        String or Array   an Array of tokens or a single
                                      token string
      notifications String or Array   an Array of notification
                                      dictionaries or a single
                                      notification dictionary

  Returns
      None

feedback

  Arguments
      app_id        String            the application id to retrieve
                                      retrieve feedback for

  Returns
      Array(Array(Datetime(time_expired), String(token)), ...)

The Python API

pyapns also provides a Python API that makes the use of pyapns even simpler. The Python API must be configured before use but configuration files make it easier. The pyapns client module currently supports configuration from Django settings and Pylons config. To configure using Django, the following must be present in your settings file:

PYAPNS_CONFIG = {
  'HOST': 'http://localhost:8077/',
  'TIMEOUT': 15,                    # OPTIONAL, host timeout in seconds
  'INITIAL': [                      # OPTIONAL, see below
    ('craigsfish', '/home/samsutch/craigsfish/apscert.pem', 'sandbox'),
  ]
}

Optionally, with Django settings, you can skip manual provisioning by including a list of (name, path, environment) tuples that are guaranteed to be provisioned by the time you call notify or feedback.

Configuring for pylons is just as simple, but automatic provisioning isn't possible, in your configuration file include:

pyapns_host = http://localhost:8077/
pyapns_timeout = 15

For explanations of the configuration variables see the docs for pyapns.client.configure.

Each of these functions can be called synchronously and asynchronously. To make them perform asynchronously simply supply a callback and pass async=True to the function. The request will then be made in another thread and your callback will be executed with the results. When calling asynchronously no value will be returned:

def got_feedback(tuples):
  trim_inactive_tokens(tuples)
feedback('myapp', async=True, callback=got_feedback)

pyapns.client.configure(opts)

Takes a dictionary of options and configures the client. 
Currently configurable options are 'HOST', 'TIMEOUT' and 'INITIAL' 
the latter of which is only read once.

Config Options:
    HOST        - A full host name with port, ending with a forward slash
    TIMEOUT     - An integer specifying how many seconds to timeout a
                  connection to the pyapns server (prevents deadlocking
                  the parent thread).
    INITIAL     - A List of tuples to be supplied to provision when
                  the first configuration happens.

pyapns.client.provision(app_id, path_to_cert_or_cert, environment, timeout=15, async=False, callback=None, errback=None)

Provisions the app_id and initializes a connection to the APNS server.
Multiple calls to this function will be ignored by the pyapns daemon
but are still sent so pick a good place to provision your apps, optimally
once.

Arguments:
    app_id                 the app_id to provision for APNS
    path_to_cert_or_cert   absolute path to the APNS SSL cert or a 
                           string containing the .pem file
    environment            either 'sandbox' or 'production'
    timeout                number of seconds to timeout connection
                           attempts to the APPLE APS SERVER
    async                  pass something truthy to execute the request in a 
                           background thread
    callback               a function to be executed with the result
    errback                a function to be executed with the error in case of an error

Returns:
    None

pyapns.client.notify(app_id, tokens, notifications, async=False, callback=None, errback=None)

Sends push notifications to the APNS server. Multiple 
notifications can be sent by sending pairing the token/notification
arguments in lists [token1, token2], [notification1, notification2].

Arguments:
    app_id                 provisioned app_id to send to
    tokens                 token to send the notification or a 
                           list of tokens
    notifications          notification dict or a list of notification dicts
    async                  pass something truthy to execute the request in a 
                           background thread
    callback               a function to be executed with the result when done
    errback                a function to be executed with the error in case of an error

  Returns:
      None

pyapns.client.feedback(app_id, async=False, callback=None, errback=None)

Retrieves a list of inactive tokens from the APNS server and the times
it thinks they went inactive.

Arguments:
    app_id                 the app_id to query
    async                  pass something truthy to execute the request in 
                           a background thread
    callback               a function to be executed with the result when 
                           feedbacks are done fetching
    errback                a function to be executed with the error if there
                           is one during the request

Returns:
    List of feedback tuples like [(datetime_expired, token_str), ...]

The Ruby API

PYAPNS::Client

There's python in my ruby!

The ruby gem can be installed from here

This is a class used to send notifications, provision applications and retrieve feedback using the Apple Push Notification Service.

PYAPNS is a multi-application APS provider, meaning it is possible to send notifications to any number of different applications from the same application and same server. It is also possible to scale the client to any number of processes and servers, simply balanced behind a simple web proxy.

It may seem like overkill for such a bare interface - after all, the APS service is rather simplistic. However, PYAPNS takes no shortcuts when it comes to completeness/compliance with the APNS protocol and allows the user many optimization and scaling vectors not possible with other libraries. No bandwidth is wasted, connections are persistent and the server is asynchronous therefore notifications are delivered immediately.

PYAPNS takes after the design of 3rd party push notification service that charge a fee each time you push a notification, and charge extra for so-called 'premium' service which supposedly gives you quicker access to the APS servers. However, PYAPNS is free, as in beer and offers more scaling opportunities without the financial draw.

Provisioning

To add your app to the PYAPNS server, it must be provisioned at least once. Normally this is done once upon the start-up of your application, be it a web service, desktop application or whatever... It must be done at least once to the server you're connecting to. Multiple instances of PYAPNS will have to have their applications provisioned individually. To provision an application manually use the PYAPNS::Client#provision method.

require 'pyapns'
client = PYAPNS::Client.configure
client.provision :app_id => 'cf', :cert => '/home/ss/cert.pem', :env => 'sandbox', :timeout => 15

This basically says "add an app reference named 'cf' to the server and start a connection using the certification, and if it can't within 15 seconds, raise a PYAPNS::TimeoutException

That's all it takes to get started. Of course, this can be done automatically by using PYAPNS::ClientConfiguration middleware. PYAPNS::Client is a singleton class that is configured using the class method PYAPNS::Client#configure. It is sensibly configured by default, but can be customized by specifying a hash See the docs on PYAPNS::ClientConfiguration for a list of available configuration parameters (some of these are important, and you can specify initial applications) to be configured by default.

Sending Notifications

Once your client is configured, and application provisioned (again, these should be taken care of before you write notification code) you can begin sending notifications to users. If you're wondering how to acquire a notification token, you've come to the wrong place... I recommend using google. However, if you want to send hundreds of millions of notifications to users, here's how it's done, one at a time...

The PYAPNS::Client#notify is a sort of polymorphic method which can notify any number of devices at a time. It's basic form is as follows:

client.notify 'cf', 'long ass app token', {:aps=> {:alert => 'hello?'}}

However, as stated before, it is sort of polymorphic:

client.notify 'cf', ['token', 'token2', 'token3'], [alert, alert2, alert3]

client.notify :app_id => 'cf', :tokens => 'mah token', :notifications => alertHash

client.notify 'cf', 'token', PYAPNS::Notification('hello tits!')

As you can see, the method accepts paralell arrays of tokens and notifications meaning any number of notifications can be sent at once. Hashes will be automatically converted to PYAPNS::Notification objects so they can be optimized for the wire (nil values removed, etc...), and you can pass PYAPNS::Notification objects directly if you wish.

Retrieving Feedback

The APS service offers a feedback functionality that allows application servers to retrieve a list of device tokens it deems to be no longer in use, and the time it thinks they stopped being useful (the user uninstalled your app, better luck next time...) Sounds pretty straight forward, and it is. Apple recommends you do this at least once an hour. PYAPNS will return a list of 2-element lists with the date and the token:

feedbacks = client.feedback 'cf'

Asynchronous Calls

PYAPNS::Client will, by default, perform no funny stuff and operate entirely within the calling thread. This means that certain applications may hang when, say, sending a notification, if only for a fraction of a second. Obviously not a desirable trait, all provision, feedback and notify methods also take a block, which indicates to the method you want to call PYAPNS asynchronously, and it will be done so handily in another thread, calling back your block with a single argument when finished. Note that notify and provision return absolutely nothing (nil, for you rub--wait you are ruby developers!). It is probably wise to always use this form of operation so your calling thread is never blocked (especially important in UI-driven apps and asynchronous servers) Just pass a block to provision/notify/feedback like so:

PYAPNS::Client.instance.feedback do |feedbacks|
  feedbacks.each { |f| trim_token f }
end

PYAPNS::ClientConfiguration

A middleware class to make PYAPNS::Client easy to use in web contexts

Automates configuration of the client in Rack environments using a simple confiuration middleware. To use PYAPNS::Client in Rack environments with the least code possible use PYAPNS::ClientConfiguration (no, really, in some cases, that's all you need!) middleware with an optional hash specifying the client variables. Options are as follows:

 use PYAPNS::ClientConfiguration(
      :host => 'http://localhost/' 
      :port => 7077,
      :initial => [{
          :app_id => 'myapp',
          :cert => '/home/myuser/apps/myapp/cert.pem',
          :env => 'sandbox',
          :timeout => 15
 }])

Where the configuration variables are defined:

:host     String      the host where the server can be found
:port     Number      the port to which the client should connect
:initial  Array       OPTIONAL - an array of INITIAL hashes

INITIAL HASHES:

:app_id   String      the id used to send messages with this certification
                      can be a totally arbitrary value
:cert     String      a path to the certification or the certification file
                      as a string
:env      String      the environment to connect to apple with, always
                      either 'sandbox' or 'production'
:timoeut  Number      The timeout for the server to use when connecting
                      to the apple servers

PYAPNS::Notification

An APNS Notification

You can construct notification objects ahead of time by using this class. However unnecessary, it allows you to programmatically generate a Notification like so:

note = PYAPNS::Notification.new 'alert text', 9, 'flynn.caf', {:extra => 'guid'}

-- or --
note = PYAPNS::Notification.new 'alert text'

These can be passed to PYAPNS::Client#notify the same as hashes