Change the way iter_participants filters are specified

readthedocs/misc/v2-migration-guide.rst

@@ -240,6 +240,25 @@ The following ``utils`` methods no longer exist or have been made private:
 // TODO provide the new clean utils
 
 
+Changes on how to configure filters for certain client methods
+--------------------------------------------------------------
+
+Before, ``client.iter_participants`` (and ``get_participants``) would expect a type or instance
+of the raw Telegram definition as a ``filter``. Now, this ``filter`` expects a string.
+The supported values are:
+
+* ``'admin'``
+* ``'bot'``
+* ``'kicked'``
+* ``'banned'``
+* ``'contact'``
+
+If you prefer to avoid hardcoding strings, you may use ``telethon.enums.Participant``.
+
+// TODO maintain support for the old way of doing it?
+// TODO now that there's a custom filter, filter client-side for small chats?
+
+
 The custom.Message class and the way it is used has changed
 -----------------------------------------------------------
 
@@ -345,12 +364,14 @@ actually using. Now it returns an ``int`` value indicating the number of message
 and were deleted.
 
 
-The aggressive parameter hack has been removed
-----------------------------------------------
+Changes to the methods to retrieve participants
+-----------------------------------------------
 
 The "aggressive" hack in ``get_participants`` (and ``iter_participants``) is now gone.
 It was not reliable, and was a cause of flood wait errors.
 
+The ``search`` parameter is no longer ignored when ``filter`` is specified.
+
 
 The total value when getting participants has changed
 -----------------------------------------------------

telethon/_client/chats.py

@@ -5,7 +5,7 @@ import string
 import typing
 
 from .. import hints, errors, _tl
-from .._misc import helpers, utils, requestiter, tlobject
+from .._misc import helpers, utils, requestiter, tlobject, enums
 from ..types import _custom
 
 if typing.TYPE_CHECKING:
@@ -95,15 +95,25 @@ class _ChatAction:
 
 class _ParticipantsIter(requestiter.RequestIter):
     async def _init(self, entity, filter, search):
-        if isinstance(filter, type):
-            if filter in (_tl.ChannelParticipantsBanned,
-                          _tl.ChannelParticipantsKicked,
-                          _tl.ChannelParticipantsSearch,
-                          _tl.ChannelParticipantsContacts):
-                # These require a `q` parameter (support types for convenience)
-                filter = filter('')
+        if not filter:
+            if search:
+                filter = _tl.ChannelParticipantsSearch(search)
             else:
-                filter = filter()
+                filter = _tl.ChannelParticipantsRecent()
+        else:
+            filter = enums.parse_participant(filter)
+            if filter == enums.Participant.ADMIN:
+                filter = _tl.ChannelParticipantsAdmins()
+            elif filter == enums.Participant.BOT:
+                filter = _tl.ChannelParticipantsBots()
+            elif filter == enums.Participant.KICKED:
+                filter = _tl.ChannelParticipantsKicked(search)
+            elif filter == enums.Participant.BANNED:
+                filter = _tl.ChannelParticipantsBanned(search)
+            elif filter == enums.Participant.CONTACT:
+                filter = _tl.ChannelParticipantsContacts(search)
+            else:
+                raise RuntimeError('unhandled enum variant')
 
         entity = await self.client.get_input_entity(entity)
         ty = helpers._entity_type(entity)

telethon/_client/telegramclient.py

@@ -729,7 +729,7 @@ class TelegramClient:
             limit: float = (),
             *,
             search: str = '',
-            filter: '_tl.TypeChannelParticipantsFilter' = None) -> chats._ParticipantsIter:
+            filter: typing.Union[str, enums.Participant] = ()) -> chats._ParticipantsIter:
         """
         Iterator over the participants belonging to the specified chat.
 
@@ -749,16 +749,22 @@ class TelegramClient:
             search (`str`, optional):
                 Look for participants with this string in name/username.
 
-            filter (:tl:`ChannelParticipantsFilter`, optional):
+                Note that the search is only compatible with some ``filter``
+                when fetching members from a channel or megagroup. This may
+                change in the future.
+
+            filter (`str`, optional):
                 The filter to be used, if you want e.g. only admins
                 Note that you might not have permissions for some filter.
                 This has no effect for normal chats or users.
 
-                .. note::
+                The available filters are:
 
-                    The filter :tl:`ChannelParticipantsBanned` will return
-                    *restricted* users. If you want *banned* users you should
-                    use :tl:`ChannelParticipantsKicked` instead.
+                * ``'admin'``
+                * ``'bot'``
+                * ``'kicked'``
+                * ``'banned'``
+                * ``'contact'``
 
         Yields
             The :tl:`User` objects returned by :tl:`GetParticipants`

telethon/_misc/enums.py

@@ -9,14 +9,29 @@ class ConnectionMode(Enum):
     HTTP = 'http'
 
 
-def parse_conn_mode(mode):
-    if isinstance(mode, ConnectionMode):
-        return mode
-    elif isinstance(mode, str):
-        for cm in ConnectionMode:
-            if mode == cm.value:
-                return cm
+class Participant(Enum):
+    ADMIN = 'admin'
+    BOT = 'bot'
+    KICKED = 'kicked'
+    BANNED = 'banned'
+    CONTACT = 'contact'
 
-        raise ValueError(f'unknown connection mode: {mode!r}')
-    else:
-        raise TypeError(f'not a valid connection mode: {type(mode).__name__!r}')
+
+def _mk_parser(cls):
+    def parser(value):
+        if isinstance(value, cls):
+            return value
+        elif isinstance(value, str):
+            for variant in cls:
+                if value == variant.value:
+                    return variant
+
+            raise ValueError(f'unknown {cls.__name__}: {value!r}')
+        else:
+            raise TypeError(f'not a valid {cls.__name__}: {type(value).__name__!r}')
+
+    return parser
+
+
+parse_conn_mode = _mk_parser(ConnectionMode)
+parse_participant = _mk_parser(Participant)

telethon/enums.py

@@ -1,3 +1,4 @@
 from ._misc.enums import (
     ConnectionMode,
+    Participant,
 )