Implemented receive timeout (#6) and fixed error string

telethon/errors.py

@@ -4,7 +4,7 @@ import re
 class ReadCancelledError(Exception):
     """Occurs when a read operation was cancelled"""
     def __init__(self):
-        super().__init__(self, 'You must run `python3 tl_generator.py` first. #ReadTheDocs!')
+        super().__init__(self, 'The read operation was cancelled.')
 
 
 class InvalidParameterError(Exception):

telethon/network/mtproto_sender.py

@@ -1,6 +1,7 @@
 import gzip
 from telethon.errors import *
 from time import sleep
+from datetime import timedelta
 from threading import Thread, RLock
 
 import telethon.helpers as utils
@@ -104,14 +105,16 @@ class MtProtoSender:
             # And update the saved session
             self.session.save()
 
-    def receive(self, request):
+    def receive(self, request, timeout=timedelta(seconds=5)):
         """Receives the specified MTProtoRequest ("fills in it"
-           the received data). This also restores the updates thread"""
+           the received data). This also restores the updates thread.
+           An optional timeout can be specified to cancel the operation
+           if no data has been read after its time delta"""
 
         with self.lock:
             # Don't stop trying to receive until we get the request we wanted
             while not request.confirm_received:
-                seq, body = self.transport.receive()
+                seq, body = self.transport.receive(timeout)
                 message, remote_msg_id, remote_sequence = self.decode_msg(body)
 
                 with BinaryReader(message) as reader:
@@ -326,19 +329,23 @@ class MtProtoSender:
 
     def updates_thread_method(self):
         """This method will run until specified and listen for incoming updates"""
+
+        # Set a reasonable timeout when checking for updates
+        timeout = timedelta(minutes=1)
+
         while self.updates_thread_running:
             # Only try to receive updates if we're not waiting to receive a request
             if not self.waiting_receive:
                 with self.lock:
                     try:
                         self.updates_thread_receiving = True
-                        seq, body = self.transport.receive()
+                        seq, body = self.transport.receive(timeout)
                         message, remote_msg_id, remote_sequence = self.decode_msg(body)
 
                         with BinaryReader(message) as reader:
                             self.process_msg(remote_msg_id, remote_sequence, reader)
 
-                    except ReadCancelledError:
+                    except (ReadCancelledError, TimeoutError):
                         pass
 
                 self.updates_thread_receiving = False

telethon/network/tcp_client.py

@@ -1,6 +1,7 @@
 # Python rough implementation of a C# TCP client
 import socket
 import time
+from datetime import datetime, timedelta
 from threading import Lock
 
 from telethon.errors import ReadCancelledError
@@ -37,8 +38,11 @@ class TcpClient:
             self.socket.setblocking(True)
             self.socket.sendall(data)
 
-    def read(self, buffer_size):
-        """Reads (receives) the specified bytes from the connected peer"""
+    def read(self, buffer_size, timeout=timedelta(seconds=5)):
+        """Reads (receives) the specified bytes from the connected peer.
+           A timeout can be specified, which will cancel the operation if no data
+           has been read in the specified time. If data was read and it's waiting
+           for more, the timeout will NOT cancel the operation. Set to None for no timeout"""
 
         # Ensure that only one thread can receive data at once
         with self.lock:
@@ -48,6 +52,10 @@ class TcpClient:
             # Set non-blocking so it can be cancelled
             self.socket.setblocking(False)
 
+            # Set the starting time so we can calculate whether the timeout should fire
+            if timeout:
+                start_time = datetime.now()
+
             with BinaryWriter() as writer:
                 while writer.written_count < buffer_size:
                     # Only do cancel if no data was read yet
@@ -66,6 +74,12 @@ class TcpClient:
                         # There was no data available for us to read. Sleep a bit
                         time.sleep(self.delay)
 
+                        # Check if the timeout finished
+                        if timeout:
+                            time_passed = datetime.now() - start_time
+                            if time_passed > timeout:
+                                raise TimeoutError('The read operation exceeded the timeout.')
+
                 # If everything went fine, return the read bytes
                 return writer.get_bytes()
 

telethon/network/tcp_transport.py

@@ -1,4 +1,6 @@
 from binascii import crc32
+from datetime import timedelta
+
 from telethon.network import TcpClient
 from telethon.errors import *
 from telethon.utils import BinaryWriter
@@ -29,19 +31,23 @@ class TcpTransport:
             self.tcp_client.write(writer.get_bytes())
             self.send_counter += 1
 
-    def receive(self):
-        """Receives a TCP message (tuple(sequence number, body)) from the connected peer"""
+    def receive(self, timeout=timedelta(seconds=5)):
+        """Receives a TCP message (tuple(sequence number, body)) from the connected peer.
+           There is a default timeout of 5 seconds before the operation is cancelled.
+           Timeout can be set to None for no timeout"""
 
         # First read everything we need
-        packet_length_bytes = self.tcp_client.read(4)
+        packet_length_bytes = self.tcp_client.read(4, timeout)
         packet_length = int.from_bytes(packet_length_bytes, byteorder='little')
 
-        seq_bytes = self.tcp_client.read(4)
+        seq_bytes = self.tcp_client.read(4, timeout)
         seq = int.from_bytes(seq_bytes, byteorder='little')
 
-        body = self.tcp_client.read(packet_length - 12)
+        body = self.tcp_client.read(packet_length - 12, timeout)
 
-        checksum = int.from_bytes(self.tcp_client.read(4), byteorder='little', signed=False)
+        checksum = int.from_bytes(self.tcp_client.read(4, timeout),
+                                  byteorder='little',
+                                  signed=False)
 
         # Then perform the checks
         rv = packet_length_bytes + seq_bytes + body

telethon/telegram_client.py

@@ -1,5 +1,5 @@
 import platform
-from datetime import datetime
+from datetime import datetime, timedelta
 from hashlib import md5
 from os import path, listdir
 from mimetypes import guess_extension, guess_type
@@ -126,13 +126,15 @@ class TelegramClient:
 
     # region Telegram requests functions
 
-    def invoke(self, request):
-        """Invokes a MTProtoRequest (sends and receives it) and returns its result"""
+    def invoke(self, request, timeout=timedelta(seconds=5)):
+        """Invokes a MTProtoRequest (sends and receives it) and returns its result.
+           An optional timeout can be given to cancel the operation after the time delta.
+           Timeout can be set to None for no timeout"""
         if not issubclass(type(request), MTProtoRequest):
             raise ValueError('You can only invoke MtProtoRequests')
 
         self.sender.send(request)
-        self.sender.receive(request)
+        self.sender.receive(request, timeout)
 
         return request.result