Add initial MQTT helper

fbchat/_mqtt.py

@@ -0,0 +1,108 @@
+import attr
+import random
+import paho.mqtt.client
+from . import _util, _graphql
+
+
+@attr.s(slots=True)
+class Mqtt:
+    _state = attr.ib()
+    _mqtt = attr.ib()
+
+    @classmethod
+    def connect(cls, state, foreground):
+        mqtt = paho.mqtt.client.Client(
+            client_id="mqttwsclient",
+            clean_session=True,
+            protocol=paho.mqtt.client.MQTTv31,
+            transport="websockets",
+        )
+        mqtt.enable_logger()
+
+        # Generate a random session ID between 1 and 9007199254740991
+        session_id = random.randint(1, 2 ** 53)
+
+        username = {
+            # The user ID
+            "u": state.user_id,
+            # Session ID
+            "s": session_id,
+            # Active status setting
+            "chat_on": True,
+            # foreground_state - Whether the window is focused
+            "fg": foreground,
+            # Can be any random ID
+            "d": state._client_id,
+            # Application ID, taken from facebook.com
+            "aid": 219994525426954,
+            # MQTT extension by FB, allows making a SUBSCRIBE while CONNECTing
+            "st": [
+                # TODO: Investigate the result from these
+                # "/inbox",
+                # "/mercury",
+                # "/messaging_events",
+                # "/orca_message_notifications",
+                # "/pp",
+                # "/t_p",
+                # "/t_rtc",
+                # "/webrtc_response",
+                "/legacy_web",
+                "/webrtc",
+                "/onevc",
+                # Things that happen in chats (e.g. messages)
+                "/t_ms",
+                # Group typing notifications
+                "/thread_typing",
+                # Private chat typing notifications
+                "/orca_typing_notifications",
+                "/notify_disconnect",
+                # Active notifications
+                "/orca_presence",
+                "/br_sr",
+                "/sr_res",
+            ],
+            # MQTT extension by FB, allows making a PUBLISH while CONNECTing
+            "pm": [],
+            # Unknown parameters
+            "cp": 3,
+            "ecp": 10,
+            "ct": "websocket",
+            "mqtt_sid": "",
+            "dc": "",
+            "no_auto_fg": True,
+            "gas": None,
+            "pack": [],
+        }
+        mqtt.username_pw_set(_util.json_minimal(username))
+
+        headers = {
+            "Cookie": _util.get_cookie_header(state._session, "edge-chat.facebook.com"),
+            "User-Agent": state._session.headers["User-Agent"],
+            "Origin": "https://www.facebook.com",
+            "Host": "edge-chat.facebook.com",
+        }
+
+        # TODO: Is region (lla | atn | odn | others?) important?
+        mqtt.ws_set_options(path="/chat?sid={}".format(session_id), headers=headers)
+        mqtt.tls_set()
+        response_code = mqtt.connect("edge-chat.facebook.com", 443, keepalive=10)
+        # TODO: Handle response code
+
+        return cls(state=state, mqtt=mqtt)
+
+    def listen(self, on_message):
+        def real_on_message(client, userdata, message):
+            on_message(message.topic, message.payload)
+
+        self._mqtt.on_message = real_on_message
+
+        self._mqtt.loop_forever()  # TODO: retry_first_connection=True?
+
+    def disconnect(self):
+        self._mqtt.disconnect()
+
+    def set_foreground(self, state):
+        payload = _util.json_minimal({"foreground": state})
+        info = self._mqtt.publish("/foreground_state", payload=payload, qos=1)
+        # TODO: We can't wait for this, since the loop is running with .loop_forever()
+        # info.wait_for_publish()

fbchat/_util.py

@@ -57,6 +57,11 @@ def now():
     return int(time() * 1000)
 
 
+def json_minimal(data):
+    """Get JSON data in minimal form."""
+    return json.dumps(data, separators=(",", ":"))
+
+
 def strip_json_cruft(text):
     """Removes `for(;;);` (and other cruft) that preceeds JSON responses."""
     try:
@@ -65,6 +70,13 @@ def strip_json_cruft(text):
         raise FBchatException("No JSON object found: {!r}".format(text))
 
 
+def get_cookie_header(session, host):
+    """Extract a cookie header from a requests session."""
+    return requests.cookies.get_cookie_header(
+        session.cookies, requests.Request("GET", host),
+    )
+
+
 def get_decoded_r(r):
     return get_decoded(r._content)