Reuse code to get chat and sender

telethon/tl/custom/sendergetter.py

@@ -0,0 +1,74 @@
+import abc
+
+
+class SenderGetter(abc.ABC):
+    """
+    Helper base class that introduces the `sender`, `input_sender`
+    and `sender_id` properties and `get_sender` and `get_input_sender`
+    methods.
+
+    Subclasses **must** have the following private members: `_sender`,
+    `_input_sender`, `_sender_id` and `_client`. As an end user, you
+    should not worry about this.
+    """
+    @property
+    def sender(self):
+        """
+        Returns the :tl:`User` that created this object. It may be ``None``
+        if the object has no sender or if Telegram didn't send the sender.
+
+        If you're using `telethon.events`, use `get_sender` instead.
+        """
+        return self._sender
+
+    async def get_sender(self):
+        """
+        Returns `sender`, but will make an API call to find the
+        sender unless it's already cached.
+        """
+        if self._sender is None and await self.get_input_sender():
+            try:
+                self._sender =\
+                    await self._client.get_entity(self._input_sender)
+            except ValueError:
+                await self._reload_message()
+        return self._sender
+
+    @property
+    def input_sender(self):
+        """
+        This :tl:`InputPeer` is the input version of the user who
+        sent the message. Similarly to `input_chat`, this doesn't have
+        things like username or similar, but still useful in some cases.
+
+        Note that this might not be available if the library can't
+        find the input chat, or if the message a broadcast on a channel.
+        """
+        if self._input_sender is None and self._sender_id:
+            try:
+                self._input_sender = self._client.session\
+                    .get_input_entity(self._sender_id)
+            except ValueError:
+                pass
+        return self._input_sender
+
+    async def get_input_sender(self):
+        """
+        Returns `input_sender`, but will make an API call to find the
+        input sender unless it's already cached.
+        """
+        if self.input_sender is None and self._sender_id:
+            await self._refetch_sender()
+        return self._input_sender
+
+    @property
+    def sender_id(self):
+        """
+        Returns the marked sender integer ID, if present.
+        """
+        return self._sender_id
+
+    async def _refetch_sender(self):
+        """
+        Re-fetches sender information through other means.
+        """