Apple DeviceCheck

Accessing and Modifying Per-Device Data

Use a token from your app to validate requests, query and modify two per-device binary digits stored on Apple servers.

Features

• Prevent API & Content abuse with validating requests via Apple device token
• Query and modify two bits of data to achieve up to four remote states saved on Apple servers
• Easy to use configuration
• Examples
• Integrations with modern web frameworks

Prepare

Visit https://developer.apple.com/account/resources/authkeys/list and create new Key with DeviceCheck permission

Install

pip install devicecheck

Usage (Python)

Setup

from devicecheck import DeviceCheck

device_check = DeviceCheck(
    team_id="XX7AN23E0Z",  # https://developer.apple.com/account/#/membership/
    bundle_id="com.akentev.app",
    key_id="JSAD983ENA",  # Generated at https://developer.apple.com/account/resources/authkeys/list
    private_key="/path/to/AuthKey_JSAD983ENA.p8",
    # Generated file at https://developer.apple.com/account/resources/authkeys/list
    dev_environment=True,  # True if using development Apple environment, False if using in production.
    # Remember to set dev_environment=False in production!
)

Asyncio setup

from devicecheck.asyncio import AsyncioDeviceCheck

The rest will be the same, except for network methods must be await'ed

Validate device

result = device_check.validate_device_token(device_token)

if result.is_ok:
    print('OK! Device is valid')
else:
    print('Bad news. Unable to validate device')

Update bits data

# Can use both integers, strings and booleans. Will be converted with bool(value)
result = device_check.update_two_bits(device_token, bit_0=1, bit_1=False)

# Can update bits separately
result = device_check.update_two_bits(device_token, bit_0=True)

if result.is_ok:
    print('Bits updated')
else:
    print(f'Something went wrong. {result}')

Query bits data

# Can use both integers, strings and booleans
result = device_check.query_two_bits(device_token)

if result.is_ok:
    print(f'First bit {result.bit_0}')  # True
    print(f'Second bit {result.bit_1}')  # False
    print(f'Last update time {result.bits_last_update_time}')  # 2020-04
else:
    print(f'Something went wrong. {result}')

Web server decorators

You can easily integrate devicecheck to your webserver using a decorator. Specify a supported framework, or leave None to try universal parser.

from devicecheck.decorators import validate_device  # for sync code
from devicecheck.decorators import DCSupportedFrameworks
from devicecheck import DeviceCheck

device_check = DeviceCheck(...)

# Set response that will be returned on invalid token
INVALID_TOKEN_RESPONSE = ('Invalid device_token', 403)


@app.route('/validate')
@validate_device(device_check, framework=DCSupportedFrameworks.flask, on_invalid_token=INVALID_TOKEN_RESPONSE)
def endpoint():
    return 'Content'

Sync code

Use sync decorator

from devicecheck.decorators import validate_device
from devicecheck.decorators import DCSupportedFrameworks

Flask

INVALID_TOKEN_RESPONSE = ('Invalid device_token', 403)
framework = DCSupportedFrameworks.flask

Async code

Use Async decorator

from devicecheck.decorators import async_validate_device
from devicecheck.decorators import DCSupportedAsyncFrameworks

Sanic

from sanic.response import text

INVALID_TOKEN_RESPONSE = text('Invalid device_token', status=403)
framework = DCSupportedAsyncFrameworks.sanic

FastAPI

from fastapi.responses import PlainTextResponse

INVALID_TOKEN_RESPONSE = PlainTextResponse('Invalid device_token', status_code=403)
framework = DCSupportedAsyncFrameworks.fastapi

Tests & Mock

Well, it's kinda hard to automate testing, because Devicecheck requires real device (Simulators won't work). In case you need to disable decorators, pass SKIP_DEVICE_CHECK_DECORATOR=True environment variable.

You can also mock validation, pass MOCK_DEVICE_CHECK_DECORATOR_TOKEN=XXXXXXXXXXXXX, it will be a hardcoded valid token value.

MOCK_DEVICE_CHECK_DECORATOR_TOKEN="device-check-token" python -m unittest tests/integrational/main.py

For Debug logs, including requests body, pass a DEBUG environment variable.

Exceptions

Library represents an AppleException class with attributes status_code and description Requires raise_on_error=True parameter for DeviceCheck instance.

Usage (Swift)

Generate device token

import DeviceCheck

public func getDeviceToken(completion: @escaping (String?) -> ()) {
    if #available(iOS 11.0, *) {
        let currentDevice = DCDevice.current
        if currentDevice.isSupported
        {
            currentDevice.generateToken(completionHandler: { (data, error) in
                if let tokenData = data {
                    let tokenString = tokenData.base64EncodedString()
                    print("Received device token")
                    completion(tokenString)
                } else{
                    print("Error generating token: \(error!.localizedDescription)")
                }
            })
        } else {
            print("Device is not supported") // Simulators or etc.
        }
    } else {
        print("Device OS is lower than iOS 11")
    }
}

Pass device token in HTTP request

Header or Body

getDeviceToken { deviceToken in
    var request = URLRequest(url: "...")
    request.httpMethod = "POST"
    
    // Header
    request.setValue(deviceToken, forHTTPHeaderField: "Device-Token")
    
    // Body
    request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
    let json = ["device_token": deviceToken] as [String : Any]
    let jsonData = try! JSONSerialization.data(withJSONObject: json)
    request.httpBody = jsonData as Data
    
    // Send it to server
    let downloadTask = URLSession.shared.dataTask(with: request, completionHandler: { data, response, error in
        ...
    })
}

License

MIT