Add iter_history method

For #170

docs/source/pyrogram/Client.rst

@@ -62,6 +62,7 @@ Messages
     delete_messages
     get_messages
     get_history
+    iter_history
     send_poll
     vote_poll
     retract_vote

pyrogram/client/methods/messages/__init__.py

@@ -25,6 +25,7 @@ from .edit_message_text import EditMessageText
 from .forward_messages import ForwardMessages
 from .get_history import GetHistory
 from .get_messages import GetMessages
+from .iter_history import IterHistory
 from .retract_vote import RetractVote
 from .send_animation import SendAnimation
 from .send_audio import SendAudio
@@ -70,6 +71,7 @@ class Messages(
     SendPoll,
     VotePoll,
     RetractVote,
-    DownloadMedia
+    DownloadMedia,
+    IterHistory
 ):
     pass

pyrogram/client/methods/messages/iter_history.py

@@ -0,0 +1,93 @@
+# Pyrogram - Telegram MTProto API Client Library for Python
+# Copyright (C) 2017-2019 Dan Tès <https://github.com/delivrance>
+#
+# This file is part of Pyrogram.
+#
+# Pyrogram is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Pyrogram is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Pyrogram.  If not, see <http://www.gnu.org/licenses/>.
+
+from typing import Union, Generator
+
+import pyrogram
+from ...ext import BaseClient
+
+
+class IterHistory(BaseClient):
+    def iter_history(self,
+                     chat_id: Union[int, str],
+                     limit: int = 0,
+                     offset: int = 0,
+                     offset_id: int = 0,
+                     offset_date: int = 0,
+                     reverse: bool = False) -> Generator["pyrogram.Message", None, None]:
+        """Use this method to iterate through a chat history sequentially.
+
+        This convenience method does the same as repeatedly calling :meth:`get_history` in a loop, thus saving you from
+        the hassle of setting up boilerplate code. It is useful for getting the whole chat history with a single call.
+
+        Args:
+            chat_id (``int`` | ``str``):
+                Unique identifier (int) or username (str) of the target chat.
+                For your personal cloud (Saved Messages) you can simply use "me" or "self".
+                For a contact that exists in your Telegram address book you can use his phone number (str).
+
+            limit (``int``, *optional*):
+                Limits the number of messages to be retrieved.
+                By default, no limit is applied and all messages are returned.
+
+            offset (``int``, *optional*):
+                Sequential number of the first message to be returned..
+                Negative values are also accepted and become useful in case you set offset_id or offset_date.
+
+            offset_id (``int``, *optional*):
+                Identifier of the first message to be returned.
+
+            offset_date (``int``, *optional*):
+                Pass a date in Unix time as offset to retrieve only older messages starting from that date.
+
+            reverse (``bool``, *optional*):
+                Pass True to retrieve the messages in reversed order (from older to most recent).
+
+        Returns:
+            A generator yielding :obj:`Message <pyrogram.Message>` objects.
+
+        Raises:
+            :class:`Error <pyrogram.Error>` in case of a Telegram RPC error.
+        """
+        offset_id = offset_id or (1 if reverse else 0)
+        current = 0
+        total = limit or (1 << 31) - 1
+        limit = min(100, total)
+
+        while True:
+            messages = self.get_history(
+                chat_id=chat_id,
+                limit=limit,
+                offset=offset,
+                offset_id=offset_id,
+                offset_date=offset_date,
+                reverse=reverse
+            ).messages
+
+            if not messages:
+                return
+
+            offset_id = messages[-1].message_id + (1 if reverse else 0)
+
+            for message in messages:
+                yield message
+
+                current += 1
+
+                if current >= total:
+                    return