Create a custom.Forward class

telethon/tl/custom/forward.py

@@ -0,0 +1,123 @@
+from ...utils import get_input_peer
+
+
+class Forward:
+    """
+    Custom class that encapsulates a :tl:`MessageFwdHeader` providing an
+    abstraction to easily access information like the original sender.
+
+    Attributes:
+
+        original_fwd (:tl:`MessageFwdHeader`):
+            The original :tl:`MessageFwdHeader` instance.
+
+        Any other attribute:
+            Attributes not described here are the same as those available
+            in the original :tl:`MessageFwdHeader`.
+    """
+    def __init__(self, client, original, entities):
+        self.__dict__ = original.__dict__
+        self._client = client
+        self.original_fwd = original
+        self._sender = entities.get(original.from_id)
+        self._chat = entities.get(original.channel_id)
+
+        self._input_sender =\
+            get_input_peer(self._sender) if self._sender else None
+        self._input_chat =\
+            get_input_peer(self._chat) if self._chat else None
+
+    # TODO The pattern to get sender and chat is very similar
+    # and copy pasted in/to several places. Reuse the code.
+    #
+    # It could be an ABC with some ``resolve_sender`` abstract,
+    # so every subclass knew what tricks it can make to get
+    # the sender.
+
+    @property
+    def sender(self):
+        """
+        The :tl:`User` that sent the original message. This may be ``None``
+        if it couldn't be found or the message wasn't forwarded from an user
+        but instead was forwarded from e.g. a channel.
+        """
+        return self._sender
+
+    async def get_sender(self):
+        """
+        Returns `sender` but will make an API if necessary.
+        """
+        if not self.sender and self.original_fwd.from_id:
+            try:
+                self._sender = await self._client.get_entity(
+                    await self.get_input_sender())
+            except ValueError:
+                # TODO We could reload the message
+                pass
+
+        return self._sender
+
+    @property
+    def input_sender(self):
+        """
+        Returns the input version of `user`.
+        """
+        if not self._input_sender and self.original_fwd.from_id:
+            try:
+                self._input_sender = self._client.session.get_input_entity(
+                    self.original_fwd.from_id)
+            except ValueError:
+                pass
+
+        return self._input_sender
+
+    async def get_input_sender(self):
+        """
+        Returns `input_sender` but will make an API call if necessary.
+        """
+        # TODO We could reload the message
+        return self.input_sender
+
+    @property
+    def chat(self):
+        """
+        The :tl:`Channel` where the original message was sent. This may be
+        ``None`` if it couldn't be found or the message wasn't forwarded
+        from a channel but instead was forwarded from e.g. an user.
+        """
+        return self._chat
+
+    async def get_chat(self):
+        """
+        Returns `chat` but will make an API if necessary.
+        """
+        if not self.chat and self.original_fwd.channel_id:
+            try:
+                self._chat = await self._client.get_entity(
+                    await self.get_input_chat())
+            except ValueError:
+                # TODO We could reload the message
+                pass
+
+        return self._chat
+
+    @property
+    def input_chat(self):
+        """
+        Returns the input version of `chat`.
+        """
+        if not self._input_chat and self.original_fwd.channel_id:
+            try:
+                self._input_chat = self._client.session.get_input_entity(
+                    self.original_fwd.channel_id)
+            except ValueError:
+                pass
+
+        return self._input_chat
+
+    async def get_input_chat(self):
+        """
+        Returns `input_chat` but will make an API call if necessary.
+        """
+        # TODO We could reload the message
+        return self.input_chat