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Refactor and improve MQTT listener a bit

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This commit is contained in:
Mads Marquart
2020-01-25 14:34:20 +01:00
parent 588c93467e
commit 2da8369c70
1 changed files with 106 additions and 98 deletions
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422
fbchat/_mqtt.py
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@@ -8,210 +8,9 @@ from . import _util, _exception, _session, _graphql, _events
from typing import Iterable, Optional
def get_cookie_header(session: requests.Session, url: str) -> str:
"""Extract a cookie header from a requests session."""
# The cookies are extracted this way to make sure they're escaped correctly
return requests.cookies.get_cookie_header(
session.cookies, requests.Request("GET", url),
)
HOST = "edge-chat.facebook.com"
def generate_session_id() -> int:
"""Generate a random session ID between 1 and 9007199254740991."""
return random.randint(1, 2 ** 53)
@attr.s(slots=True, kw_only=kw_only, repr=False, eq=False)
class Listener:
"""Helper, to listen for incoming Facebook events."""
session = attr.ib(type=_session.Session)
_mqtt = attr.ib(type=paho.mqtt.client.Client)
_chat_on = attr.ib(type=bool)
_foreground = attr.ib(type=bool)
_sequence_id = attr.ib(type=int)
_sync_token = attr.ib(None, type=str)
_tmp_events = attr.ib(None, type=Optional[Iterable[_events.Event]])
_HOST = "edge-chat.facebook.com"
def __repr__(self) -> str:
# An alternative repr, to illustrate that you can't create the class directly
return "<fbchat.Listener session={} chat_on={} foreground={}>".format(
self.session, self._chat_on, self._foreground
)
@classmethod
def connect(cls, session: _session.Session, chat_on: bool, foreground: bool):
"""Initialize a connection to the Facebook MQTT service.
Args:
session: The session to use when making requests.
chat_on: Whether ...
foreground: Whether ...
Example:
>>> listener = fbchat.Listener.connect(session, chat_on=True, foreground=True)
"""
mqtt = paho.mqtt.client.Client(
client_id="mqttwsclient",
clean_session=True,
protocol=paho.mqtt.client.MQTTv31,
transport="websockets",
)
mqtt.enable_logger()
# mqtt.max_inflight_messages_set(20) # The rest will get queued
# mqtt.max_queued_messages_set(0) # Unlimited messages can be queued
# mqtt.message_retry_set(20) # Retry sending for at least 20 seconds
# mqtt.reconnect_delay_set(min_delay=1, max_delay=120)
# TODO: Is region (lla | atn | odn | others?) important?
mqtt.tls_set()
self = cls(
session=session,
mqtt=mqtt,
chat_on=chat_on,
foreground=foreground,
sequence_id=cls._fetch_sequence_id(session),
)
# Configure callbacks
mqtt.on_message = self._on_message_handler
mqtt.on_connect = self._on_connect_handler
self._configure_connect_options()
# Attempt to connect
try:
rc = mqtt.connect(self._HOST, 443, keepalive=10)
except (
# Taken from .loop_forever
paho.mqtt.client.socket.error,
OSError,
paho.mqtt.client.WebsocketConnectionError,
) as e:
raise _exception.FacebookError("MQTT connection failed") from e
# Raise error if connecting failed
if rc != paho.mqtt.client.MQTT_ERR_SUCCESS:
err = paho.mqtt.client.error_string(rc)
raise _exception.FacebookError("MQTT connection failed: {}".format(err))
return self
def _on_message_handler(self, client, userdata, message):
# Parse payload JSON
try:
j = _util.parse_json(message.payload.decode("utf-8"))
except (_exception.FacebookError, UnicodeDecodeError):
log.debug(message.payload)
log.exception("Failed parsing MQTT data on %s as JSON", message.topic)
return
log.debug("MQTT payload: %s, %s", message.topic, j)
if message.topic == "/t_ms":
# Update sync_token when received
# This is received in the first message after we've created a messenger
# sync queue.
if "syncToken" in j and "firstDeltaSeqId" in j:
self._sync_token = j["syncToken"]
self._sequence_id = j["firstDeltaSeqId"]
return
if "errorCode" in j:
error = j["errorCode"]
# TODO: 'F\xfa\x84\x8c\x85\xf8\xbc-\x88 FB_PAGES_INSUFFICIENT_PERMISSION\x00'
if error in ("ERROR_QUEUE_NOT_FOUND", "ERROR_QUEUE_OVERFLOW"):
# ERROR_QUEUE_NOT_FOUND means that the queue was deleted, since too
# much time passed, or that it was simply missing
# ERROR_QUEUE_OVERFLOW means that the sequence id was too small, so
# the desired events could not be retrieved
log.error(
"The MQTT listener was disconnected for too long,"
" events may have been lost"
)
self._sync_token = None
self._sequence_id = self._fetch_sequence_id(self.session)
self._messenger_queue_publish()
# TODO: Signal to the user that they should reload their data!
return
log.error("MQTT error code %s received", error)
return
# Update last sequence id when received
if "lastIssuedSeqId" in j:
self._sequence_id = j["lastIssuedSeqId"]
else:
log.error("Missing last sequence id: %s", j)
try:
# TODO: Don't handle this in a callback
self._tmp_events = list(
_events.parse_events(self.session, message.topic, j)
)
except _exception.ParseError:
log.exception("Failed parsing MQTT data")
@staticmethod
def _fetch_sequence_id(session: _session.Session) -> int:
"""Fetch sequence ID."""
params = {
"limit": 0,
"tags": ["INBOX"],
"before": None,
"includeDeliveryReceipts": False,
"includeSeqID": True,
}
log.debug("Fetching MQTT sequence ID")
# Same request as in `Client.fetch_threads`
(j,) = session._graphql_requests(
_graphql.from_doc_id("1349387578499440", params)
)
sequence_id = j["viewer"]["message_threads"]["sync_sequence_id"]
if not sequence_id:
raise _exception.NotLoggedIn("Failed fetching sequence id")
return int(sequence_id)
def _on_connect_handler(self, client, userdata, flags, rc):
if rc == 21:
raise _exception.FacebookError(
"Failed connecting. Maybe your cookies are wrong?"
)
if rc != 0:
return # Don't try to send publish if the connection failed
self._messenger_queue_publish()
def _messenger_queue_publish(self):
# configure receiving messages.
payload = {
"sync_api_version": 10,
"max_deltas_able_to_process": 1000,
"delta_batch_size": 500,
"encoding": "JSON",
"entity_fbid": self.session.user.id,
}
# If we don't have a sync_token, create a new messenger queue
# This is done so that across reconnects, if we've received a sync token, we
# SHOULD receive a piece of data in /t_ms exactly once!
if self._sync_token is None:
topic = "/messenger_sync_create_queue"
payload["initial_titan_sequence_id"] = str(self._sequence_id)
payload["device_params"] = None
else:
topic = "/messenger_sync_get_diffs"
payload["last_seq_id"] = str(self._sequence_id)
payload["sync_token"] = self._sync_token
self._mqtt.publish(topic, _util.json_minimal(payload), qos=1)
def _configure_connect_options(self):
# Generate a new session ID on each reconnect
session_id = generate_session_id()
topics = [
TOPICS = [
# Things that happen in chats (e.g. messages)
"/t_ms",
# Group typing notifications
@@ -248,6 +47,216 @@ class Listener:
"/webrtc_response",
]
def get_cookie_header(session: requests.Session, url: str) -> str:
"""Extract a cookie header from a requests session."""
# The cookies are extracted this way to make sure they're escaped correctly
return requests.cookies.get_cookie_header(
session.cookies, requests.Request("GET", url),
)
def generate_session_id() -> int:
"""Generate a random session ID between 1 and 9007199254740991."""
return random.randint(1, 2 ** 53)
def fetch_sequence_id(session: _session.Session) -> int:
"""Fetch sequence ID."""
params = {
"limit": 0,
"tags": ["INBOX"],
"before": None,
"includeDeliveryReceipts": False,
"includeSeqID": True,
}
log.debug("Fetching MQTT sequence ID")
# Same doc id as in `Client.fetch_threads`
(j,) = session._graphql_requests(_graphql.from_doc_id("1349387578499440", params))
sequence_id = j["viewer"]["message_threads"]["sync_sequence_id"]
if not sequence_id:
raise _exception.NotLoggedIn("Failed fetching sequence id")
return int(sequence_id)
@attr.s(slots=True, kw_only=kw_only, repr=False, eq=False)
class Listener:
"""Helper, to listen for incoming Facebook events."""
session = attr.ib(type=_session.Session)
_mqtt = attr.ib(type=paho.mqtt.client.Client)
_chat_on = attr.ib(type=bool)
_foreground = attr.ib(type=bool)
_sequence_id = attr.ib(type=int)
_sync_token = attr.ib(None, type=str)
_tmp_events = attr.ib(None, type=Optional[Iterable[_events.Event]])
def __repr__(self) -> str:
# An alternative repr, to illustrate that you can't create the class directly
return "<fbchat.Listener session={} chat_on={} foreground={}>".format(
self.session, self._chat_on, self._foreground
)
@classmethod
def connect(cls, session: _session.Session, chat_on: bool, foreground: bool):
"""Initialize a connection to the Facebook MQTT service.
Args:
session: The session to use when making requests.
chat_on: Whether ...
foreground: Whether ...
Example:
>>> listener = fbchat.Listener.connect(session, chat_on=True, foreground=True)
"""
mqtt = paho.mqtt.client.Client(
client_id="mqttwsclient",
clean_session=True,
protocol=paho.mqtt.client.MQTTv31,
transport="websockets",
)
mqtt.enable_logger()
# mqtt.max_inflight_messages_set(20) # The rest will get queued
# mqtt.max_queued_messages_set(0) # Unlimited messages can be queued
# mqtt.message_retry_set(20) # Retry sending for at least 20 seconds
# mqtt.reconnect_delay_set(min_delay=1, max_delay=120)
mqtt.tls_set()
self = cls(
session=session,
mqtt=mqtt,
chat_on=chat_on,
foreground=foreground,
sequence_id=fetch_sequence_id(session),
)
# Configure callbacks
mqtt.on_message = self._on_message_handler
mqtt.on_connect = self._on_connect_handler
self._configure_connect_options()
# Attempt to connect
try:
rc = mqtt.connect(HOST, 443, keepalive=10)
except (
# Taken from .loop_forever
paho.mqtt.client.socket.error,
OSError,
paho.mqtt.client.WebsocketConnectionError,
) as e:
raise _exception.FacebookError("MQTT connection failed") from e
# Raise error if connecting failed
if rc != paho.mqtt.client.MQTT_ERR_SUCCESS:
err = paho.mqtt.client.error_string(rc)
raise _exception.FacebookError("MQTT connection failed: {}".format(err))
return self
def _handle_ms(self, j):
"""Handle /t_ms special logic.
Returns whether to continue parsing the message.
"""
# TODO: Merge this with the parsing in _events
# Update sync_token when received
# This is received in the first message after we've created a messenger
# sync queue.
if "syncToken" in j and "firstDeltaSeqId" in j:
self._sync_token = j["syncToken"]
self._sequence_id = j["firstDeltaSeqId"]
return False
if "errorCode" in j:
error = j["errorCode"]
# TODO: 'F\xfa\x84\x8c\x85\xf8\xbc-\x88 FB_PAGES_INSUFFICIENT_PERMISSION\x00'
if error in ("ERROR_QUEUE_NOT_FOUND", "ERROR_QUEUE_OVERFLOW"):
# ERROR_QUEUE_NOT_FOUND means that the queue was deleted, since too
# much time passed, or that it was simply missing
# ERROR_QUEUE_OVERFLOW means that the sequence id was too small, so
# the desired events could not be retrieved
log.error(
"The MQTT listener was disconnected for too long,"
" events may have been lost"
)
self._sync_token = None
self._sequence_id = fetch_sequence_id(self.session)
self._messenger_queue_publish()
# TODO: Signal to the user that they should reload their data!
return False
log.error("MQTT error code %s received", error)
return False
# Update last sequence id
# Except for the two cases above, this is always received
self._sequence_id = j["lastIssuedSeqId"]
return True
def _on_message_handler(self, client, userdata, message):
# Parse payload JSON
try:
j = _util.parse_json(message.payload.decode("utf-8"))
except (_exception.FacebookError, UnicodeDecodeError):
log.debug(message.payload)
log.exception("Failed parsing MQTT data on %s as JSON", message.topic)
return
log.debug("MQTT payload: %s, %s", message.topic, j)
if message.topic == "/t_ms":
if not _handle_ms(j):
return
try:
# TODO: Don't handle this in a callback
self._tmp_events = list(
_events.parse_events(self.session, message.topic, j)
)
except _exception.ParseError:
log.exception("Failed parsing MQTT data")
def _on_connect_handler(self, client, userdata, flags, rc):
if rc == 21:
raise _exception.FacebookError(
"Failed connecting. Maybe your cookies are wrong?"
)
if rc != 0:
err = paho.mqtt.client.connack_string(rc)
log.error("MQTT Connection Error: %s", err)
return # Don't try to send publish if the connection failed
self._messenger_queue_publish()
def _messenger_queue_publish(self):
# configure receiving messages.
payload = {
"sync_api_version": 10,
"max_deltas_able_to_process": 1000,
"delta_batch_size": 500,
"encoding": "JSON",
"entity_fbid": self.session.user.id,
}
# If we don't have a sync_token, create a new messenger queue
# This is done so that across reconnects, if we've received a sync token, we
# SHOULD receive a piece of data in /t_ms exactly once!
if self._sync_token is None:
topic = "/messenger_sync_create_queue"
payload["initial_titan_sequence_id"] = str(self._sequence_id)
payload["device_params"] = None
else:
topic = "/messenger_sync_get_diffs"
payload["last_seq_id"] = str(self._sequence_id)
payload["sync_token"] = self._sync_token
self._mqtt.publish(topic, _util.json_minimal(payload), qos=1)
def _configure_connect_options(self):
# Generate a new session ID on each reconnect
session_id = generate_session_id()
username = {
# The user ID
"u": self.session.user.id,
@@ -262,7 +271,7 @@ class Listener:
# Application ID, taken from facebook.com
"aid": 219994525426954,
# MQTT extension by FB, allows making a SUBSCRIBE while CONNECTing
"st": topics,
"st": TOPICS,
# MQTT extension by FB, allows making a PUBLISH while CONNECTing
# Using this is more efficient, but the same can be acheived with:
# def on_connect(*args):
@@ -288,19 +297,18 @@ class Listener:
"pack": [],
}
# TODO: Make this thread safe
self._mqtt.username_pw_set(_util.json_minimal(username))
headers = {
# TODO: Make this access thread safe
"Cookie": get_cookie_header(
self.session._session, "https://edge-chat.facebook.com/chat"
),
"User-Agent": self.session._session.headers["User-Agent"],
"Origin": "https://www.facebook.com",
"Host": self._HOST,
"Host": HOST,
}
# TODO: Is region (lla | atn | odn | others?) important?
self._mqtt.ws_set_options(
path="/chat?sid={}".format(session_id), headers=headers
)