Implemented register_for_reply. Closes #26

telebot/__init__.py

@@ -95,6 +95,9 @@ class TeleBot:
         self.num_threads = num_threads
         self.__create_threads = create_threads
 
+        self.message_subscribers_messages = []
+        self.message_subscribers_callbacks = []
+
         self.message_handlers = []
         if self.__create_threads:
             self.worker_pool = ThreadPool(num_threads)
@@ -119,6 +122,7 @@ class TeleBot:
     def process_new_messages(self, new_messages):
         self.__notify_update(new_messages)
         self._notify_command_handlers(new_messages)
+        self._notify_message_subscribers(new_messages)
 
     def __notify_update(self, new_messages):
         for listener in self.update_listener:
@@ -234,7 +238,7 @@ class TeleBot:
     def send_document(self, chat_id, data, reply_to_message_id=None, reply_markup=None):
         """
         Use this method to send general files.
-        :param chat_id:
+        :param c.append()hat_id:
         :param data:
         :param reply_to_message_id:
         :param reply_markup:
@@ -293,8 +297,41 @@ class TeleBot:
         return apihelper.send_chat_action(self.token, chat_id, action)
 
     def reply_to(self, message, text, **kwargs):
+        """
+        Convenience function for `send_message(message.chat.id, text, reply_to_message_id=message.message_id, **kwargs)`
+        """
         return self.send_message(message.chat.id, text, reply_to_message_id=message.message_id, **kwargs)
 
+    def register_for_reply(self, message, callback):
+        """
+        Registers a callback function to be notified when a reply to `message` arrives.
+
+        Warning: `message` must be sent with reply_markup=types.ForceReply(), otherwise TeleBot will not be able to see
+        the difference between a reply to `message` and an ordinary message.
+
+        :param message:     The message for which we are awaiting a reply.
+        :param callback:    The callback function to be called when a reply arrives. Must accept one `message`
+                            parameter, which will contain the replied message.
+        """
+        self.message_subscribers_messages.insert(0, message.message_id)
+        self.message_subscribers_callbacks.insert(0, callback)
+        if len(self.message_subscribers_messages) > 10000:
+            self.message_subscribers_messages.pop()
+            self.message_subscribers_callbacks.pop()
+
+    def _notify_message_subscribers(self, new_messages):
+        for message in new_messages:
+            if not hasattr(message, 'reply_to_message'):
+                continue
+
+            reply_msg_id = message.reply_to_message.message_id
+            if reply_msg_id in self.message_subscribers_messages:
+                index = self.message_subscribers_messages.index(reply_msg_id)
+                self.message_subscribers_callbacks[index](message)
+
+                del self.message_subscribers_messages[index]
+                del self.message_subscribers_callbacks[index]
+
     def message_handler(self, commands=None, regexp=None, func=None, content_types=['text']):
         """
         Message handler decorator.

tests/test_telebot.py

@@ -123,6 +123,18 @@ def test_reply_to():
     ret_msg = tb.reply_to(msg, text + ' REPLY')
     assert ret_msg.reply_to_message.message_id == msg.message_id
 
+def test_register_for_reply():
+    text = 'CI reply_to Test Message'
+    tb = telebot.TeleBot(TOKEN)
+    msg = tb.send_message(CHAT_ID, text, reply_markup=types.ForceReply())
+    reply_msg = tb.reply_to(msg, text + ' REPLY')
+
+    def process_reply(message):
+        assert msg.message_id == message.reply_to_message.message_id
+
+    tb.register_for_reply(msg, process_reply)
+
+    tb.process_new_messages([reply_msg])
 
 def test_send_location():
     tb = telebot.TeleBot(TOKEN)