Require stricter object names (#2146)

sanic/app.py

@@ -135,13 +135,8 @@ class Sanic(BaseSanic):
         register: Optional[bool] = None,
         dumps: Optional[Callable[..., str]] = None,
     ) -> None:
-        super().__init__()
+        super().__init__(name=name)
 
-        if name is None:
-            raise SanicException(
-                "Sanic instance cannot be unnamed. "
-                "Please use Sanic(name='your_application_name') instead.",
-            )
         # logging
         if configure_logging:
             logging.config.dictConfig(log_config or LOGGING_CONFIG_DEFAULTS)
@@ -161,7 +156,6 @@ class Sanic(BaseSanic):
         self.is_running = False
         self.is_stopping = False
         self.listeners: Dict[str, List[ListenerType]] = defaultdict(list)
-        self.name = name
         self.named_request_middleware: Dict[str, Deque[MiddlewareType]] = {}
         self.named_response_middleware: Dict[str, Deque[MiddlewareType]] = {}
         self.request_class = request_class

sanic/base.py

@@ -1,6 +1,9 @@
+import re
+
 from typing import Any, Tuple
 from warnings import warn
 
+from sanic.exceptions import SanicException
 from sanic.mixins.exceptions import ExceptionMixin
 from sanic.mixins.listeners import ListenerMixin
 from sanic.mixins.middleware import MiddlewareMixin
@@ -8,6 +11,9 @@ from sanic.mixins.routes import RouteMixin
 from sanic.mixins.signals import SignalMixin
 
 
+VALID_NAME = re.compile(r"^[a-zA-Z][a-zA-Z0-9_\-]*$")
+
+
 class BaseSanic(
     RouteMixin,
     MiddlewareMixin,
@@ -17,7 +23,25 @@ class BaseSanic(
 ):
     __fake_slots__: Tuple[str, ...]
 
-    def __init__(self, *args, **kwargs) -> None:
+    def __init__(self, name: str = None, *args, **kwargs) -> None:
+        class_name = self.__class__.__name__
+
+        if name is None:
+            raise SanicException(
+                f"{class_name} instance cannot be unnamed. "
+                "Please use Sanic(name='your_application_name') instead.",
+            )
+
+        if not VALID_NAME.match(name):
+            warn(
+                f"{class_name} instance named '{name}' uses a format that is"
+                f"deprecated. Starting in version 21.12, {class_name} objects "
+                "be named only using alphanumeric characters, _, or -.",
+                DeprecationWarning,
+            )
+
+        self.name = name
+
         for base in BaseSanic.__bases__:
             base.__init__(self, *args, **kwargs)  # type: ignore
 
@@ -36,6 +60,7 @@ class BaseSanic(
                 f"Setting variables on {self.__class__.__name__} instances is "
                 "deprecated and will be removed in version 21.9. You should "
                 f"change your {self.__class__.__name__} instance to use "
-                f"instance.ctx.{name} instead."
+                f"instance.ctx.{name} instead.",
+                DeprecationWarning,
             )
         super().__setattr__(name, value)

sanic/blueprints.py

@@ -62,19 +62,20 @@ class Blueprint(BaseSanic):
         "strict_slashes",
         "url_prefix",
         "version",
+        "version_prefix",
         "websocket_routes",
     )
 
     def __init__(
         self,
-        name: str,
+        name: str = None,
         url_prefix: Optional[str] = None,
         host: Optional[str] = None,
         version: Optional[Union[int, str, float]] = None,
         strict_slashes: Optional[bool] = None,
         version_prefix: str = "/v",
     ):
-        super().__init__()
+        super().__init__(name=name)
 
         self._apps: Set[Sanic] = set()
         self.ctx = SimpleNamespace()
@@ -82,7 +83,6 @@ class Blueprint(BaseSanic):
         self.host = host
         self.listeners: Dict[str, List[ListenerType]] = {}
         self.middlewares: List[MiddlewareType] = []
-        self.name = name
         self.routes: List[Route] = []
         self.statics: List[RouteHandler] = []
         self.strict_slashes = strict_slashes

sanic/mixins/routes.py

@@ -26,10 +26,11 @@ from sanic.views import CompositionView
 
 
 class RouteMixin:
+    name: str
+
     def __init__(self, *args, **kwargs) -> None:
         self._future_routes: Set[FutureRoute] = set()
         self._future_statics: Set[FutureStatic] = set()
-        self.name = ""
         self.strict_slashes: Optional[bool] = False
 
     def _apply_route(self, route: FutureRoute) -> List[Route]: