From bb607e56be6e219582d96f28aa318b5a37cfa96c Mon Sep 17 00:00:00 2001
From: JosXa <joscha.goetzer@gmail.com>
Date: Mon, 30 Apr 2018 00:15:24 +0200
Subject: [PATCH 1/2] Added locks for modifying and iterating handlers Added
 `remove_handler` method Made `add_handler` return a (handler, group) tuple

---
 pyrogram/client/client.py                | 18 +++++++-
 pyrogram/client/dispatcher/dispatcher.py | 55 ++++++++++++++----------
 2 files changed, 50 insertions(+), 23 deletions(-)

diff --git a/pyrogram/client/client.py b/pyrogram/client/client.py
index 07679545..8fb3e500 100644
--- a/pyrogram/client/client.py
+++ b/pyrogram/client/client.py
@@ -245,7 +245,7 @@ class Client:
         return decorator
 
     def add_handler(self, handler, group: int = 0):
-        """Use this method to register an event handler.
+        """Use this method to register an update handler.
 
         You can register multiple handlers, but at most one handler within a group
         will be used for a single event. To handle the same event more than once, register
@@ -260,6 +260,22 @@ class Client:
         """
         self.dispatcher.add_handler(handler, group)
 
+    def remove_handler(self, handler, group: int = 0):
+        """Removes a previously-added update handler.
+
+        Make sure to provide the right group that the handler was added in. You can use
+        the return value of the ``add_handler`` method, a tuple of (handler, group), and
+        pass it directly.
+
+        Args:
+            handler (``Handler``):
+                The handler to be removed.
+
+            group (``int``, optional):
+                The group identifier, defaults to 0.
+        """
+        self.dispatcher.remove_handler(handler, group)
+
     def start(self, debug: bool = False):
         """Use this method to start the Client after creating it.
         Requires no parameters.
diff --git a/pyrogram/client/dispatcher/dispatcher.py b/pyrogram/client/dispatcher/dispatcher.py
index 6f96876c..cf6912f5 100644
--- a/pyrogram/client/dispatcher/dispatcher.py
+++ b/pyrogram/client/dispatcher/dispatcher.py
@@ -50,6 +50,8 @@ class Dispatcher:
         self.updates = Queue()
         self.groups = OrderedDict()
 
+        self._handler_lock = threading.Lock()
+
     def start(self):
         for i in range(self.workers):
             self.workers_list.append(
@@ -69,36 +71,45 @@ class Dispatcher:
             i.join()
 
     def add_handler(self, handler, group: int):
-        if group not in self.groups:
-            self.groups[group] = []
-            self.groups = OrderedDict(sorted(self.groups.items()))
+        with self._handler_lock:
+            if group not in self.groups:
+                self.groups[group] = []
+                self.groups = OrderedDict(sorted(self.groups.items()))
 
-        self.groups[group].append(handler)
+            self.groups[group].append(handler)
+
+    def remove_handler(self, handler, group: int):
+        with self._handler_lock:
+            if group not in self.groups:
+                raise ValueError("Group {} does not exist. "
+                                 "Handler was not removed.".format(group))
+            self.groups[group].remove(handler)
 
     def dispatch(self, update, users: dict = None, chats: dict = None, is_raw: bool = False):
-        for group in self.groups.values():
-            for handler in group:
-                if is_raw:
-                    if not isinstance(handler, RawUpdateHandler):
-                        continue
+        with self._handler_lock:
+            for group in self.groups.values():
+                for handler in group:
+                    if is_raw:
+                        if not isinstance(handler, RawUpdateHandler):
+                            continue
 
-                    args = (self.client, update, users, chats)
-                else:
-                    if not isinstance(handler, MessageHandler):
-                        continue
+                        args = (self.client, update, users, chats)
+                    else:
+                        if not isinstance(handler, MessageHandler):
+                            continue
 
-                    message = (update.message
-                               or update.channel_post
-                               or update.edited_message
-                               or update.edited_channel_post)
+                        message = (update.message
+                                   or update.channel_post
+                                   or update.edited_message
+                                   or update.edited_channel_post)
 
-                    if not handler.check(message):
-                        continue
+                        if not handler.check(message):
+                            continue
 
-                    args = (self.client, message)
+                        args = (self.client, message)
 
-                handler.callback(*args)
-                break
+                    handler.callback(*args)
+                    break
 
     def update_worker(self):
         name = threading.current_thread().name

From f824e69b5a2449fd01121f75b504235fc15c1a47 Mon Sep 17 00:00:00 2001
From: Dan <14043624+delivrance@users.noreply.github.com>
Date: Mon, 30 Apr 2018 10:15:34 +0200
Subject: [PATCH 2/2] Update client.py

---
 pyrogram/client/client.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/pyrogram/client/client.py b/pyrogram/client/client.py
index 8fb3e500..1a8b2578 100644
--- a/pyrogram/client/client.py
+++ b/pyrogram/client/client.py
@@ -243,12 +243,13 @@ class Client:
             return func
 
         return decorator
-
+    
+    # TODO: Maybe make add_handler return (handler, group)?
     def add_handler(self, handler, group: int = 0):
         """Use this method to register an update handler.
 
         You can register multiple handlers, but at most one handler within a group
-        will be used for a single event. To handle the same event more than once, register
+        will be used for a single update. To handle the same update more than once, register
         your handler using a different group id (lower group id == higher priority).
 
         Args:
@@ -264,7 +265,7 @@ class Client:
         """Removes a previously-added update handler.
 
         Make sure to provide the right group that the handler was added in. You can use
-        the return value of the ``add_handler`` method, a tuple of (handler, group), and
+        the return value of the :meth:`add_handler` method, a tuple of (handler, group), and
         pass it directly.
 
         Args: