AirPlay Support

Currently there is some AirPlay functionality supported in pyatv, but it is very limited. Only two features are supported:

  • Device authentication

  • Playing media via URL

Additional features will be added as needed.

Device Authentication

In tvOS 10.2, Apple started to enforce a feature called “device authentication”. This requires every device that streams content via AirPlay to enter a PIN code the first time before playback is started. Once done, the user will never have to do this again. The actual feature has been available for a while but as opt-in, so it would have to be explicitly enabled. Now it is enabled by default and cannot be disabled. Devices not running tvOS (e.g. Apple TV 2nd and 3rd generation) are not affected, even though device authentication can be enabled on theses devices as well.

The device authentication process is based on the Secure Remote Password protocol (SRP), with slight modifications. All the reverse engineering required for this process was made by funtax (GitHub username) and has merly been ported to python for usage in this library. Please see references at bottom of page for reference implementation.

Generating credentials

When performing device authentication, a device identifier and a private key is required. Once authenticated, they can be used to authenticate without using a PIN code. So they must be saved and re-used whenever something is to be played.

In this library, the device identifier and private key is called AirPlay credentials and are concatenated into a string, using : as separator. An example might look like this:

D9B75D737BE2F0F1:6A26D8EB6F4AE2408757D5CA5FF9C37E96BEBB22C632426C4A02AD4FA895A85B
       ^                       ^
  Identifier              Private key

New (random) credentials can be generated and loaded in the following way:

credentials = yield from atv.airplay.generate_credentials()
yield from atv.airplay.load_credentials(credentials)

It is important to load the newly created credentials as they are not automatically loaded when being generated. This is also how previously authenticated credentials are re-used.

Note

There is no builtin support for storing credentials. It is up to the application to handle this.

API Reference: pyatv.interface.AirPlay.generate_credentials(), pyatv.interface.AirPlay.load_credentials()

Authenticating credentials

Performing the authentication requires two steps. First, the process must be initiated with the device so that a PIN code is displayed. Then it can be completed by providing the PIN code back to the library:

yield from atv.airplay.start_authentication()
pin = ...  # Get PIN from user
yield from atv.airplay.finish_authentication(pin)

If the authentication process fails, a pyatv.exceptions.DeviceAuthenticationError is raised.

API Reference: pyatv.interface.AirPlay.start_authentication(), pyatv.interface.AirPlay.finish_authentication()

Verifying credentials

To verify if the loaded credentials are authenticated, verify_authenticated can be used:

credentials = ...
yield from atv.airplay.load_credentials(credentials)
yield from atv.airplay.verify_authenticated()

If the credentials are not properly authenticated, a pyatv.exceptions.DeviceAuthenticationError is raised.

API Reference: pyatv.interface.AirPlay.verify_authenticated()

Example

A complete code example of the authentication might look like this (it’s available under examples):

import sys
import asyncio
from pyatv import (exceptions, helpers)


@asyncio.coroutine
def authenticate_with_device(atv):
    """Perform device authentication and print credentials."""
    credentials = yield from atv.airplay.generate_credentials()
    yield from atv.airplay.load_credentials(credentials)

    try:
        yield from atv.airplay.start_authentication()
        pin = input('PIN Code: ')
        yield from atv.airplay.finish_authentication(pin)
        print('Credentials: {0}'.format(credentials))

    except exceptions.DeviceAuthenticationError:
        print('Failed to authenticate', file=sys.stderr)


helpers.auto_connect(authenticate_with_device)

Playing media

Playing a URL is as simple as passing the URL to play_url:

url = 'http://...'
yield from atv.airplay.play_url(url)

If the device requires device authentication, valid credentials must be loaded using pyatv.interface.AirPlay.load_credentials() first. Otherwise an error message will be shown on the screen.