typing: avoid protocols for handlers

falcon/http_error.py

@@ -26,9 +26,9 @@
 from falcon.util.deprecation import deprecated_args
 
 if TYPE_CHECKING:
+    from falcon.media import BaseHandler
     from falcon.typing import HeaderList
     from falcon.typing import Link
-    from falcon.typing import Serializer
     from falcon.typing import Status
 
 
@@ -191,7 +191,7 @@ def to_dict(
 
         return obj
 
-    def to_json(self, handler: Optional[Serializer] = None) -> bytes:
+    def to_json(self, handler: Optional[BaseHandler] = None) -> bytes:
         """Return a JSON representation of the error.
 
         Args:
@@ -241,6 +241,6 @@ def to_xml(self) -> bytes:
 # NOTE: initialized in falcon.media.json, that is always imported since Request/Response
 # are imported by falcon init.
 if TYPE_CHECKING:
-    _DEFAULT_JSON_HANDLER: Serializer
+    _DEFAULT_JSON_HANDLER: BaseHandler
 else:
     _DEFAULT_JSON_HANDLER = None

falcon/media/handlers.py

@@ -1,12 +1,13 @@
 from collections import UserDict
 import functools
-import typing
+from typing import Mapping
 
 from falcon import errors
 from falcon.constants import MEDIA_JSON
 from falcon.constants import MEDIA_MULTIPART
 from falcon.constants import MEDIA_URLENCODED
 from falcon.constants import PYPY
+from falcon.media.base import BaseHandler
 from falcon.media.base import BinaryBaseHandlerWS
 from falcon.media.json import JSONHandler
 from falcon.media.multipart import MultipartFormHandler
@@ -16,11 +17,6 @@
 from falcon.util import misc
 from falcon.vendor import mimeparse
 
-if typing.TYPE_CHECKING:  # pragma: no cover
-    from typing import Mapping
-
-    from falcon.typing import Serializer
-
 
 class MissingDependencyHandler(BinaryBaseHandlerWS):
     """Placeholder handler that always raises an error.
@@ -41,13 +37,13 @@ def _raise(self, *args, **kwargs):
     serialize = deserialize = _raise
 
 
-class Handlers(UserDict):
+class Handlers(UserDict[str, BaseHandler]):
     """A :class:`dict`-like object that manages Internet media type handlers."""
 
     def __init__(self, initial=None):
         self._resolve = self._create_resolver()
 
-        handlers: Mapping[str, Serializer] = initial or {
+        handlers: Mapping[str, BaseHandler] = initial or {
             MEDIA_JSON: JSONHandler(),
             MEDIA_MULTIPART: MultipartFormHandler(),
             MEDIA_URLENCODED: URLEncodedFormHandler(),

falcon/response.py

@@ -18,7 +18,7 @@
 
 import functools
 import mimetypes
-from typing import Optional, TYPE_CHECKING
+from typing import Dict, Optional
 
 from falcon.constants import _DEFAULT_STATIC_MEDIA_TYPES
 from falcon.constants import _UNSET
@@ -41,9 +41,6 @@
 from falcon.util.uri import encode_check_escaped as uri_encode
 from falcon.util.uri import encode_value_check_escaped as uri_encode_value
 
-if TYPE_CHECKING:
-    from falcon.typing import MediaHandlers
-
 GMT_TIMEZONE = TimezoneGMT()
 
 _STREAM_LEN_REMOVED_MSG = (
@@ -1256,8 +1253,8 @@ class ResponseOptions:
 
     secure_cookies_by_default: bool
     default_media_type: Optional[str]
-    media_handlers: MediaHandlers
-    static_media_types: dict
+    media_handlers: Handlers
+    static_media_types: Dict[str, str]
 
     __slots__ = (
         'secure_cookies_by_default',

falcon/typing.py

@@ -21,32 +21,16 @@
     Callable,
     Dict,
     List,
-    MutableMapping,
-    Optional,
     Pattern,
     Tuple,
     TYPE_CHECKING,
     Union,
 )
 
 if TYPE_CHECKING:
-    from typing import Protocol
-
     from falcon.request import Request
     from falcon.response import Response
 
-    class Serializer(Protocol):
-        def serialize(
-            self,
-            media: MutableMapping[str, Union[str, int, None, Link]],
-            content_type: str,
-        ) -> bytes: ...
-
-    class MediaHandlers(Protocol):
-        def _resolve(
-            self, media_type: str, default: str, raise_not_found: bool = False
-        ) -> Tuple[Serializer, Optional[Callable], Optional[Callable]]: ...
-
 
 Link = Dict[str, str]