Merge pull request #331 from pyrogram/I329

Closes #329

pyrogram/client/client.py

@@ -328,12 +328,18 @@ class Client(Methods, BaseClient):
 
         self.is_initialized = True
 
-    def terminate(self):
+    def terminate(self, block: bool = True):
         """Terminate the client by shutting down workers.
 
         This method does the opposite of :meth:`~Client.initialize`.
         It will stop the dispatcher and shut down updates and download workers.
 
+        Parameters:
+            block (``bool``, *optional*):
+                Blocks the code execution until the client has been terminated. It is useful with ``block=False`` in
+                case you want to terminate the own client *within* an handler in order not to cause a deadlock.
+                Defaults to True.
+
         Raises:
             ConnectionError: In case you try to terminate a client that is already terminated.
         """
@@ -345,7 +351,7 @@ class Client(Methods, BaseClient):
             log.warning("Takeout session {} finished".format(self.takeout_id))
 
         Syncer.remove(self)
-        self.dispatcher.stop()
+        self.dispatcher.stop(block)
 
         for _ in range(self.DOWNLOAD_WORKERS):
             self.download_queue.put(None)
@@ -840,11 +846,17 @@ class Client(Methods, BaseClient):
             self.initialize()
             return self
 
-    def stop(self):
+    def stop(self, block: bool = True):
         """Stop the Client.
 
         This method disconnects the client from Telegram and stops the underlying tasks.
 
+        Parameters:
+            block (``bool``, *optional*):
+                Blocks the code execution until the client has been stopped. It is useful with ``block=False`` in case
+                you want to stop the own client *within* an handler in order not to cause a deadlock.
+                Defaults to True.
+
         Returns:
             :obj:`Client`: The stopped client itself.
 
@@ -864,17 +876,23 @@ class Client(Methods, BaseClient):
 
                 app.stop()
         """
-        self.terminate()
+        self.terminate(block)
         self.disconnect()
 
         return self
 
-    def restart(self):
+    def restart(self, block: bool = True):
         """Restart the Client.
 
         This method will first call :meth:`~Client.stop` and then :meth:`~Client.start` in a row in order to restart
         a client using a single method.
 
+        Parameters:
+            block (``bool``, *optional*):
+                Blocks the code execution until the client has been restarted. It is useful with ``block=False`` in case
+                you want to restart the own client *within* an handler in order not to cause a deadlock.
+                Defaults to True.
+
         Returns:
             :obj:`Client`: The restarted client itself.
 
@@ -898,7 +916,7 @@ class Client(Methods, BaseClient):
 
                 app.stop()
         """
-        self.stop()
+        self.stop(block)
         self.start()
 
         return self
@@ -985,7 +1003,7 @@ class Client(Methods, BaseClient):
         Client.idle()
         self.stop()
 
-    def add_handler(self, handler: Handler, group: int = 0):
+    def add_handler(self, handler: Handler, group: int = 0, block: bool = True):
         """Register an update handler.
 
         You can register multiple handlers, but at most one handler within a group will be used for a single update.
@@ -1000,6 +1018,11 @@ class Client(Methods, BaseClient):
             group (``int``, *optional*):
                 The group identifier, defaults to 0.
 
+            block (``bool``, *optional*):
+                Blocks the code execution until the handler has been added. It is useful with ``block=False`` in case
+                you want to register a new handler *within* another handler in order not to cause a deadlock.
+                Defaults to True.
+
         Returns:
             ``tuple``: A tuple consisting of *(handler, group)*.
 
@@ -1021,11 +1044,11 @@ class Client(Methods, BaseClient):
         if isinstance(handler, DisconnectHandler):
             self.disconnect_handler = handler.callback
         else:
-            self.dispatcher.add_handler(handler, group)
+            self.dispatcher.add_handler(handler, group, block)
 
         return handler, group
 
-    def remove_handler(self, handler: Handler, group: int = 0):
+    def remove_handler(self, handler: Handler, group: int = 0, block: bool = True):
         """Remove a previously-registered update handler.
 
         Make sure to provide the right group where the handler was added in. You can use the return value of the
@@ -1038,6 +1061,13 @@ class Client(Methods, BaseClient):
             group (``int``, *optional*):
                 The group identifier, defaults to 0.
 
+            block (``bool``, *optional*):
+                Blocks the code execution until the handler has been removed. It is useful with ``block=False`` in case
+                you want to remove a previously registered handler *within* another handler in order not to cause a
+                deadlock.
+                Defaults to True.
+
+
         Example:
             .. code-block:: python
                 :emphasize-lines: 11
@@ -1059,7 +1089,7 @@ class Client(Methods, BaseClient):
         if isinstance(handler, DisconnectHandler):
             self.disconnect_handler = None
         else:
-            self.dispatcher.remove_handler(handler, group)
+            self.dispatcher.remove_handler(handler, group, block)
 
     def stop_transmission(self):
         """Stop downloading or uploading a file.

pyrogram/client/ext/dispatcher.py

@@ -118,43 +118,61 @@ class Dispatcher:
 
             self.workers_list[-1].start()
 
-    def stop(self):
-        for _ in range(self.workers):
-            self.updates_queue.put(None)
+    def stop(self, block: bool = True):
+        def do_it():
+            for _ in range(self.workers):
+                self.updates_queue.put(None)
 
-        for worker in self.workers_list:
-            worker.join()
+            for worker in self.workers_list:
+                worker.join()
 
-        self.workers_list.clear()
-        self.locks_list.clear()
-        self.groups.clear()
+            self.workers_list.clear()
+            self.locks_list.clear()
+            self.groups.clear()
 
-    def add_handler(self, handler, group: int):
-        for lock in self.locks_list:
-            lock.acquire()
+        if block:
+            do_it()
+        else:
+            Thread(target=do_it).start()
 
-        try:
-            if group not in self.groups:
-                self.groups[group] = []
-                self.groups = OrderedDict(sorted(self.groups.items()))
-
-            self.groups[group].append(handler)
-        finally:
+    def add_handler(self, handler, group: int, block: bool = True):
+        def do_it():
             for lock in self.locks_list:
-                lock.release()
+                lock.acquire()
 
-    def remove_handler(self, handler, group: int):
-        for lock in self.locks_list:
-            lock.acquire()
+            try:
+                if group not in self.groups:
+                    self.groups[group] = []
+                    self.groups = OrderedDict(sorted(self.groups.items()))
 
-        try:
-            if group not in self.groups:
-                raise ValueError("Group {} does not exist. Handler was not removed.".format(group))
+                self.groups[group].append(handler)
+            finally:
+                for lock in self.locks_list:
+                    lock.release()
 
-            self.groups[group].remove(handler)
-        finally:
+        if block:
+            do_it()
+        else:
+            Thread(target=do_it).start()
+
+    def remove_handler(self, handler, group: int, block: bool = True):
+        def do_it():
             for lock in self.locks_list:
-                lock.release()
+                lock.acquire()
+
+            try:
+                if group not in self.groups:
+                    raise ValueError("Group {} does not exist. Handler was not removed.".format(group))
+
+                self.groups[group].remove(handler)
+            finally:
+                for lock in self.locks_list:
+                    lock.release()
+
+        if block:
+            do_it()
+        else:
+            Thread(target=do_it).start()
 
     def update_worker(self, lock):
         name = threading.current_thread().name