Improve listening usability

Add Listener.register and Listener.run

docs/intro.rst

@@ -134,17 +134,18 @@ Listening & Events
 
 Now, we are finally at the point we have all been waiting for: Creating an automatic Facebook bot!
 
-To get started, you create your methods that will handle your events::
+To get started, you create a listener object::
 
-    def on_message(event):
+    listener = fbchat.Listener(session=session, chat_on=False, foreground=False)
+
+The you use that to register methods that will handle your events::
+
+    @listener.register
+    def on_message(event: fbchat.MessageEvent):
         print(f"Message from {event.author.id}: {event.message.text}")
 
-And then you create a listener object, and start handling the incoming events::
+And then you start handling the incoming events::
 
-    listener = fbchat.Listener.connect(session, False, False)
-
-    for event in listener.listen():
-        if isinstance(event, fbchat.MessageEvent):
-            on_message(event)
+    listener.run()
 
 View the :ref:`examples` to see some more examples illustrating the event system.

examples/echobot.py

@@ -1,17 +1,15 @@
 import fbchat
 
 session = fbchat.Session.login("<email>", "<password>")
-
-listener = fbchat.Listener.connect(session, chat_on=False, foreground=False)
+listener = fbchat.Listener(session=session, chat_on=False, foreground=False)
 
 
-def on_message(event):
+@listener.register
+def on_message(event: fbchat.MessageEvent):
     print(f"{event.message.text} from {event.author.id} in {event.thread.id}")
     # If you're not the author, echo
     if event.author.id != session.user.id:
         event.thread.send_text(event.message.text)
 
 
-for event in listener.listen():
-    if isinstance(event, fbchat.MessageEvent):
-        on_message(event)
+listener.run()

examples/keepbot.py

@@ -15,10 +15,10 @@ old_nicknames = {
 }
 
 session = fbchat.Session.login("<email>", "<password>")
-
-listener = fbchat.Listener.connect(session, chat_on=False, foreground=False)
+listener = fbchat.Listener(session=session, chat_on=False, foreground=False)
 
 
+@listener.register
 def on_color_set(event: fbchat.ColorSet):
     if old_thread_id != event.thread.id:
         return
@@ -27,6 +27,7 @@ def on_color_set(event: fbchat.ColorSet):
         event.thread.set_color(old_color)
 
 
+@listener.register
 def on_emoji_set(event: fbchat.EmojiSet):
     if old_thread_id != event.thread.id:
         return
@@ -35,6 +36,7 @@ def on_emoji_set(event: fbchat.EmojiSet):
         event.thread.set_emoji(old_emoji)
 
 
+@listener.register
 def on_title_set(event: fbchat.TitleSet):
     if old_thread_id != event.thread.id:
         return
@@ -43,6 +45,7 @@ def on_title_set(event: fbchat.TitleSet):
         event.thread.set_title(old_title)
 
 
+@listener.register
 def on_nickname_set(event: fbchat.NicknameSet):
     if old_thread_id != event.thread.id:
         return
@@ -55,6 +58,7 @@ def on_nickname_set(event: fbchat.NicknameSet):
         event.thread.set_nickname(event.subject.id, old_nickname)
 
 
+@listener.register
 def on_people_added(event: fbchat.PeopleAdded):
     if old_thread_id != event.thread.id:
         return
@@ -64,6 +68,7 @@ def on_people_added(event: fbchat.PeopleAdded):
             event.thread.remove_participant(added.id)
 
 
+@listener.register
 def on_person_removed(event: fbchat.PersonRemoved):
     if old_thread_id != event.thread.id:
         return
@@ -75,16 +80,4 @@ def on_person_removed(event: fbchat.PersonRemoved):
         event.thread.add_participants([removed.id])
 
 
-for event in listener.listen():
-    if isinstance(event, fbchat.ColorSet):
-        on_color_set(event)
-    elif isinstance(event, fbchat.EmojiSet):
-        on_emoji_set(event)
-    elif isinstance(event, fbchat.TitleSet):
-        on_title_set(event)
-    elif isinstance(event, fbchat.NicknameSet):
-        on_nickname_set(event)
-    elif isinstance(event, fbchat.PeopleAdded):
-        on_people_added(event)
-    elif isinstance(event, fbchat.PersonRemoved):
-        on_person_removed(event)
+listener.run()

examples/removebot.py

@@ -1,10 +1,10 @@
 import fbchat
 
 session = fbchat.Session.login("<email>", "<password>")
-
-listener = fbchat.Listener.connect(session, chat_on=False, foreground=False)
+listener = fbchat.Listener(session=session, chat_on=False, foreground=False)
 
 
+@listener.register
 def on_message(event):
     # We can only kick people from group chats, so no need to try if it's a user chat
     if not isinstance(event.thread, fbchat.Group):
@@ -14,6 +14,4 @@ def on_message(event):
         event.thread.remove_participant(event.author.id)
 
 
-for event in listener.listen():
-    if isinstance(event, fbchat.MessageEvent):
-        on_message(event)
+listener.run()

fbchat/_listen.py

@@ -1,11 +1,12 @@
 import attr
+import inspect
 import random
 import paho.mqtt.client
 import requests
 from ._common import log, kw_only
 from . import _util, _exception, _session, _graphql, _events
 
-from typing import Iterable, Optional
+from typing import Iterable, Optional, Mapping, Callable
 
 
 HOST = "edge-chat.facebook.com"
@@ -97,6 +98,9 @@ def fetch_sequence_id(session: _session.Session) -> int:
     return int(sequence_id)
 
 
+HandlerT = Callable[[_events.Event], None]
+
+
 @attr.s(slots=True, kw_only=kw_only, eq=False)
 class Listener:
     """Helper, to listen for incoming Facebook events.
@@ -119,6 +123,7 @@ class Listener:
     _sync_token = attr.ib(None, type=Optional[str])
     _sequence_id = attr.ib(None, type=Optional[int])
     _tmp_events = attr.ib(factory=list, type=Iterable[_events.Event])
+    _handlers = attr.ib(factory=dict, type=Mapping[HandlerT, _events.Event])
 
     def __attrs_post_init__(self):
         # Configure callbacks
@@ -302,7 +307,8 @@ class Listener:
 
         Yields events when they arrive.
 
-        This will automatically reconnect on errors.
+        This will automatically reconnect on errors, except if the errors are one of
+        `PleaseRefresh` or `NotLoggedIn`.
 
         Example:
             Print events continually.
@@ -398,3 +404,57 @@ class Listener:
     #
     # def browser_close(self):
     #     info = self._mqtt.publish("/browser_close", payload=b"{}", qos=1)
+
+    def register(func: HandlerT) -> HandlerT:
+        """Register a function that will be called when .run is called.
+
+        The input function must take a single annotated argument.
+
+        Should be used as a function decorator.
+
+        Example:
+            >>> @listener.register
+            >>> def my_handler(event: fbchat.Event):
+            ...     print(f"New event: {event}")
+        """
+        try:
+            parameter = next(iter(inspect.signature(func).parameters.values()))
+        except Exception as e:  # TODO: More precise exceptions
+            raise ValueError("Invalid function. Must have at least an argument") from e
+
+        if parameter.annotation is parameter.empty:
+            raise ValueError("Invalid function. Must be annotated")
+
+        if not issubclass(parameter.annotation, _events.Event):
+            raise ValueError("Invalid function. Annotation must be an event class")
+
+        # TODO: More error checks, e.g. kw_only parameters
+
+        self._handlers[func] = parameter.annotation
+
+    def unregister(func: HandlerT):
+        """Unregister a previously registered function."""
+        try:
+            self._handlers.pop(func)
+        except KeyError:
+            raise ValueError("Tried to unregister a function that was not registered")
+
+    def run(self) -> None:
+        """Run the listening loop, and dispatch incoming events to registered handlers.
+
+        This uses `.listen`, which reconnect on errors, except if the errors are one of
+        `PleaseRefresh` or `NotLoggedIn`.
+
+        Example:
+            Print incoming messages.
+
+            >>> @listener.register
+            >>> def print_msg(event: fbchat.MessageEvent):
+            ...     print(event.message.text)
+            ...
+            >>> listener.run()
+        """
+        for event in self.listen():
+            for handler, event_cls in self._handlers.items():
+                if isinstance(event, event_cls):
+                    handler(event)