Continue work on the basic bot code

core.py

@@ -2,11 +2,13 @@ import os
 import sys
 import configparser
 import telegram
-import threading
 import time
 import strings
 import worker
 
+def main():
+    """The core code of the program. Should be run only in the main process!"""
+
     # Check if a configuration file exists, create one if it doesn't and get the template version number.
     with open("config/template_config.ini") as template_file:
         # Check if the config file exists
@@ -61,10 +63,10 @@ chat_workers = {}
     # Current update offset; if None it will get the last 100 unparsed messages
     next_update = None
 
-
     # Main loop of the program
     while True:
         # Get a new batch of 100 updates and mark the last 100 parsed as read
+        # TODO: handle possible errors
         updates = bot.get_updates(offset=next_update)
         # Parse all the updates
         for update in updates:
@@ -97,19 +99,30 @@ while True:
                 if receiving_worker is None:
                     # Suggest that the user restarts the chat with /start
                     bot.send_message(update.message.chat.id, strings.error_no_worker_for_chat)
+                    # Skip the update
+                    continue
                 # Forward the update to the worker
                 receiving_worker.pipe.send(update)
             # If the update is a inline keyboard press...
             if update.inline_query is not None:
                 # Forward the update to the corresponding worker
-            receiving_worker = chat_workers.get(update.message.chat.id)
+                receiving_worker = chat_workers.get(update.inline_query.chat.id)
                 # Ensure a worker exists for the chat
                 if receiving_worker is None:
                     # Suggest that the user restarts the chat with /start
-                bot.send_message(update.message.chat.id, strings.error_no_worker_for_chat)
+                    bot.send_message(update.inline_query.chat.id, strings.error_no_worker_for_chat)
+                    # Skip the update
+                    continue
                 # Forward the update to the worker
                 receiving_worker.pipe.send(update)
-        # Mark the update as read by increasing the update_offset
-        next_update = update.update_id + 1
+        # If there were any updates...
+        if len(updates):
+            # Mark them as read by increasing the update_offset
+            next_update = updates[-1].update_id + 1
         # Temporarily prevent rate limits (remove this later)
         time.sleep(5)
+
+
+# Run the main function only in the main process
+if __name__ == "__main__":
+    main()

strings.py

@@ -1,5 +1,10 @@
 # Strings / localization file for greed
 # Can be edited, but DON'T REMOVE THE REPLACEMENT FIELDS (words surrounded by {curly braces})
+# TODO: maybe add a preformat to all strings in this file
+
+# Answer: the start command was sent and the bot should welcome the user
+conversation_after_start = "Ciao!\n" \
+                           "Benvenuto su greed!"
 
 # Error: message received not in a private chat
 error_nonprivate_chat = "⚠️ Questo bot funziona solo in chat private."

worker.py

@@ -1,12 +1,20 @@
 import multiprocessing
 import telegram
+import strings
+
+class StopSignal:
+    """A data class that should be sent to the worker when the conversation has to be stopped abnormally."""
+
+    def __init__(self, reason: str=""):
+        self.reason = reason
+
 
 class ChatWorker:
     """A worker for a single conversation. A new one should be created every time the /start command is sent."""
 
     def __init__(self, bot: telegram.Bot, chat: telegram.Chat):
         # A pipe connecting the main process to the chat process is created
-        in_pipe, out_pipe = multiprocessing.Pipe(duplex=False)
+        out_pipe, in_pipe = multiprocessing.Pipe(duplex=False)
         # The sending pipe is stored in the ChatWorker class, allowing the forwarding of messages to the chat process
         self.pipe = in_pipe
         # A new process running the conversation handler is created, and the receiving pipe is passed to its arguments to enable the receiving of messages
@@ -16,13 +24,40 @@ class ChatWorker:
         """Start the worker process."""
         self.process.start()
 
-    def stop(self):
-        # Gracefully stop the worker process
-        # TODO: send a stop message to the process
-        raise NotImplementedError()
+    def stop(self, reason: str=""):
+        """Gracefully stop the worker process"""
+        # Send a stop message to the process
+        self.pipe.send(StopSignal(reason))
         # Wait for the process to stop
         self.process.join()
 
 
-def conversation_handler(bot: telegram.Bot, chat: telegram.Chat, pipe: multiprocessing.Connection):
+def receive_next_update(pipe) -> telegram.Update:
+    """Get the next update from a pipe.
+    If no update is found, block the process until one is received.
+    If a stop signal is sent, try to gracefully stop the process."""
+    # Receive data from the pipe
+    data = pipe.recv()
+    # Check if the data is a stop signal instance
+    if isinstance(data, StopSignal):
+        # Gracefully stop the process
+        graceful_stop()
+    # Return the received update
+    return data
+
+
+def graceful_stop():
+    """Handle the graceful stop of the process."""
     raise NotImplementedError()
+
+
+def conversation_handler(bot: telegram.Bot, chat: telegram.Chat, pipe):
+    """This function is ran once for every conversation (/start command) by a separate process."""
+    # TODO: catch all the possible exceptions
+    # Welcome the user to the bot
+    bot.send_message(chat.id, strings.conversation_after_start)
+    # TODO: Send a command list or something
+    while True:
+        # For now, echo the sent message
+        update = receive_next_update(pipe)
+        bot.send_message(chat.id, update.message.text)