import collections import json import logging from enum import Enum from .errors import ConnectionFailed, exception_class_for_reason # We don't generally need to know about the Credentials subclasses except to # keep the old API, where APNsClient took a cert_file from .credentials import CertificateCredentials class NotificationPriority(Enum): Immediate = '10' Delayed = '5' RequestStream = collections.namedtuple('RequestStream', ['stream_id', 'token']) Notification = collections.namedtuple('Notification', ['token', 'payload']) DEFAULT_APNS_PRIORITY = NotificationPriority.Immediate CONCURRENT_STREAMS_SAFETY_MAXIMUM = 1000 MAX_CONNECTION_RETRIES = 3 logger = logging.getLogger(__name__) class APNsClient(object): SANDBOX_SERVER = 'api.development.push.apple.com' LIVE_SERVER = 'api.push.apple.com' DEFAULT_PORT = 443 ALTERNATIVE_PORT = 2197 def __init__(self, credentials, use_sandbox=False, use_alternative_port=False, proto=None, json_encoder=None, password=None, proxy_host=None, proxy_port=None): if credentials is None or isinstance(credentials, str): self.__credentials = CertificateCredentials(credentials, password) else: self.__credentials = credentials self._init_connection(use_sandbox, use_alternative_port, proto, proxy_host, proxy_port) self.__json_encoder = json_encoder self.__max_concurrent_streams = None self.__previous_server_max_concurrent_streams = None def _init_connection(self, use_sandbox, use_alternative_port, proto, proxy_host, proxy_port): server = self.SANDBOX_SERVER if use_sandbox else self.LIVE_SERVER port = self.ALTERNATIVE_PORT if use_alternative_port else self.DEFAULT_PORT self._connection = self.__credentials.create_connection(server, port, proto, proxy_host, proxy_port) def send_notification(self, token_hex, notification, topic=None, priority=NotificationPriority.Immediate, expiration=None, collapse_id=None): stream_id = self.send_notification_async(token_hex, notification, topic, priority, expiration, collapse_id) result = self.get_notification_result(stream_id) if result != 'Success': raise exception_class_for_reason(result) def send_notification_async(self, token_hex, notification, topic=None, priority=NotificationPriority.Immediate, expiration=None, collapse_id=None): json_str = json.dumps(notification.dict(), cls=self.__json_encoder, ensure_ascii=False, separators=(',', ':')) json_payload = json_str.encode('utf-8') headers = {} if topic is not None: headers['apns-topic'] = topic if priority != DEFAULT_APNS_PRIORITY: headers['apns-priority'] = priority.value if expiration is not None: headers['apns-expiration'] = '%d' % expiration auth_header = self.__credentials.get_authorization_header(topic) if auth_header is not None: headers['authorization'] = auth_header if collapse_id is not None: headers['apns-collapse-id'] = collapse_id url = '/3/device/{}'.format(token_hex) stream_id = self._connection.request('POST', url, json_payload, headers) return stream_id def get_notification_result(self, stream_id): with self._connection.get_response(stream_id) as response: if response.status == 200: return 'Success' else: raw_data = response.read().decode('utf-8') data = json.loads(raw_data) return data['reason'] def send_notification_batch(self, notifications, topic=None, priority=NotificationPriority.Immediate, expiration=None, collapse_id=None): """ Send a notification to a list of tokens in batch. Instead of sending a synchronous request for each token, send multiple requests concurrently. This is done on the same connection, using HTTP/2 streams (one request per stream). APNs allows many streams simultaneously, but the number of streams can vary depending on server load. This method reads the SETTINGS frame sent by the server to figure out the maximum number of concurrent streams. Typically, APNs reports a maximum of 500. The function returns a dictionary mapping each token to its result. The result is "Success" if the token was sent successfully, or the string returned by APNs in the 'reason' field of the response, if the token generated an error. """ notification_iterator = iter(notifications) next_notification = next(notification_iterator, None) # Make sure we're connected to APNs, so that we receive and process the server's SETTINGS # frame before starting to send notifications. self.connect() results = {} open_streams = collections.deque() # Loop on the tokens, sending as many requests as possible concurrently to APNs. # When reaching the maximum concurrent streams limit, wait for a response before sending # another request. while len(open_streams) > 0 or next_notification is not None: # Update the max_concurrent_streams on every iteration since a SETTINGS frame can be # sent by the server at any time. self.update_max_concurrent_streams() if self.should_send_notification(next_notification, open_streams): logger.info('Sending to token %s', next_notification.token) stream_id = self.send_notification_async(next_notification.token, next_notification.payload, topic, priority, expiration, collapse_id) open_streams.append(RequestStream(stream_id, next_notification.token)) next_notification = next(notification_iterator, None) if next_notification is None: # No tokens remaining. Proceed to get results for pending requests. logger.info('Finished sending all tokens, waiting for pending requests.') else: # We have at least one request waiting for response (otherwise we would have either # sent new requests or exited the while loop.) Wait for the first outstanding stream # to return a response. pending_stream = open_streams.popleft() result = self.get_notification_result(pending_stream.stream_id) logger.info('Got response for %s: %s', pending_stream.token, result) results[pending_stream.token] = result return results def should_send_notification(self, notification, open_streams): return notification is not None and len(open_streams) < self.__max_concurrent_streams def update_max_concurrent_streams(self): # Get the max_concurrent_streams setting returned by the server. # The max_concurrent_streams value is saved in the H2Connection instance that must be # accessed using a with statement in order to acquire a lock. # pylint: disable=protected-access with self._connection._conn as connection: max_concurrent_streams = connection.remote_settings.max_concurrent_streams if max_concurrent_streams == self.__previous_server_max_concurrent_streams: # The server hasn't issued an updated SETTINGS frame. return self.__previous_server_max_concurrent_streams = max_concurrent_streams # Handle and log unexpected values sent by APNs, just in case. if max_concurrent_streams > CONCURRENT_STREAMS_SAFETY_MAXIMUM: logger.warning('APNs max_concurrent_streams too high (%s), resorting to default maximum (%s)', max_concurrent_streams, CONCURRENT_STREAMS_SAFETY_MAXIMUM) self.__max_concurrent_streams = CONCURRENT_STREAMS_SAFETY_MAXIMUM elif max_concurrent_streams < 1: logger.warning('APNs reported max_concurrent_streams less than 1 (%s), using value of 1', max_concurrent_streams) self.__max_concurrent_streams = 1 else: logger.info('APNs set max_concurrent_streams to %s', max_concurrent_streams) self.__max_concurrent_streams = max_concurrent_streams def connect(self): """ Establish a connection to APNs. If already connected, the function does nothing. If the connection fails, the function retries up to MAX_CONNECTION_RETRIES times. """ retries = 0 while retries < MAX_CONNECTION_RETRIES: try: self._connection.connect() logger.info('Connected to APNs') return except Exception: # pylint: disable=broad-except # close the connnection, otherwise next connect() call would do nothing self._connection.close() retries += 1 logger.exception('Failed connecting to APNs (attempt %s of %s)', retries, MAX_CONNECTION_RETRIES) raise ConnectionFailed()