Generate deserializers for requests

client/src/telethon/_impl/tl/core/__init__.py

@@ -1,5 +1,24 @@
-from .reader import Reader
+from .reader import (
+    Reader,
+    deserialize_bool,
+    deserialize_i32_list,
+    deserialize_i64_list,
+    deserialize_identity,
+    list_deserializer,
+    single_deserializer,
+)
 from .request import Request
 from .serializable import Serializable, serialize_bytes_to
 
-__all__ = ["Reader", "Request", "Serializable", "serialize_bytes_to"]
+__all__ = [
+    "Reader",
+    "deserialize_bool",
+    "deserialize_i32_list",
+    "deserialize_i64_list",
+    "deserialize_identity",
+    "list_deserializer",
+    "single_deserializer",
+    "Request",
+    "Serializable",
+    "serialize_bytes_to",
+]

client/src/telethon/_impl/tl/core/reader.py

@@ -1,5 +1,6 @@
+import functools
 import struct
-from typing import TYPE_CHECKING, Any, Optional, Type, TypeVar
+from typing import TYPE_CHECKING, Any, Callable, List, Optional, Type, TypeVar
 
 if TYPE_CHECKING:
     from .serializable import Serializable
@@ -85,3 +86,47 @@ class Reader:
             raise ValueError(f"No type found for constructor ID: {cid:x}")
         assert issubclass(ty, cls)
         return ty._read_from(self)
+
+
+@functools.cache
+def single_deserializer(cls: Type[T]) -> Callable[[bytes], T]:
+    def deserializer(body: bytes) -> T:
+        return Reader(body).read_serializable(cls)
+
+    return deserializer
+
+
+@functools.cache
+def list_deserializer(cls: Type[T]) -> Callable[[bytes], List[T]]:
+    def deserializer(body: bytes) -> List[T]:
+        reader = Reader(body)
+        vec_id, length = reader.read_fmt("<ii", 8)
+        assert vec_id == 0x1CB5C415 and length >= 0
+        return [reader.read_serializable(cls) for _ in range(length)]
+
+    return deserializer
+
+
+def deserialize_i64_list(body: bytes) -> List[int]:
+    reader = Reader(body)
+    vec_id, length = reader.read_fmt("<ii", 8)
+    assert vec_id == 0x1CB5C415 and length >= 0
+    return [*reader.read_fmt(f"<{length}q", length * 8)]
+
+
+def deserialize_i32_list(body: bytes) -> List[int]:
+    reader = Reader(body)
+    vec_id, length = reader.read_fmt("<ii", 8)
+    assert vec_id == 0x1CB5C415 and length >= 0
+    return [*reader.read_fmt(f"<{length}i", length * 4)]
+
+
+def deserialize_identity(body: bytes) -> bytes:
+    return body
+
+
+def deserialize_bool(body: bytes) -> bool:
+    reader = Reader(body)
+    bool_id = reader.read_fmt("<I", 4)[0]
+    assert isinstance(bool_id, int) and bool_id in (0x997275B5, 0xBC799737)
+    return bool_id == 0x997275B5

client/src/telethon/_impl/tl/core/request.py

@@ -1,9 +1,28 @@
 import struct
-from typing import Generic, TypeVar
+from typing import Any, Callable, Generic, Optional, TypeVar
 
 Return = TypeVar("Return")
 
 
+def _bootstrap_get_deserializer(
+    constructor_id: int,
+) -> Optional[Callable[[bytes], Any]]:
+    # Similar to Reader's bootstrapping.
+    if Request._get_deserializer is _bootstrap_get_deserializer:
+        from ..layer import RESPONSE_MAPPING as API_DESER
+        from ..mtproto.layer import RESPONSE_MAPPING as MTPROTO_DESER
+
+        if API_DESER.keys() & MTPROTO_DESER.keys():
+            raise RuntimeError(
+                "generated api and mtproto schemas cannot have colliding constructor identifiers"
+            )
+        ALL_DESER = API_DESER | MTPROTO_DESER
+
+        Request._get_deserializer = ALL_DESER.get  # type: ignore [assignment]
+
+    return Request._get_deserializer(constructor_id)
+
+
 class Request(bytes, Generic[Return]):
     __slots__ = ()
 
@@ -16,5 +35,12 @@ class Request(bytes, Generic[Return]):
         except struct.error:
             return 0
 
+    _get_deserializer = staticmethod(_bootstrap_get_deserializer)
+
+    def deserialize_response(self, response: bytes) -> Return:
+        deserializer = self._get_deserializer(self.constructor_id)
+        assert deserializer is not None
+        return deserializer(response)  # type: ignore [no-any-return]
+
     def debug_name(self) -> str:
         return f"request#{self.constructor_id:x}"