Do not apply double slash to Blueprint and static dirs (#2515)

sanic/blueprints.py

@@ -308,7 +308,7 @@ class Blueprint(BaseSanic):
             # prefixed properly in the router
             future.handler.__blueprintname__ = self.name
             # Prepend the blueprint URI prefix if available
-            uri = url_prefix + future.uri if url_prefix else future.uri
+            uri = self._setup_uri(future.uri, url_prefix)
 
             version_prefix = self.version_prefix
             for prefix in (
@@ -333,7 +333,7 @@ class Blueprint(BaseSanic):
 
             apply_route = FutureRoute(
                 future.handler,
-                uri[1:] if uri.startswith("//") else uri,
+                uri,
                 future.methods,
                 host,
                 strict_slashes,
@@ -363,7 +363,7 @@ class Blueprint(BaseSanic):
         # Static Files
         for future in self._future_statics:
             # Prepend the blueprint URI prefix if available
-            uri = url_prefix + future.uri if url_prefix else future.uri
+            uri = self._setup_uri(future.uri, url_prefix)
             apply_route = FutureStatic(uri, *future[1:])
 
             if (self, apply_route) in app._future_registry:
@@ -456,6 +456,18 @@ class Blueprint(BaseSanic):
                 break
         return value
 
+    @staticmethod
+    def _setup_uri(base: str, prefix: Optional[str]):
+        uri = base
+        if prefix:
+            uri = prefix
+            if base.startswith("/") and prefix.endswith("/"):
+                uri += base[1:]
+            else:
+                uri += base
+
+        return uri[1:] if uri.startswith("//") else uri
+
     @staticmethod
     def register_futures(
         apps: Set[Sanic], bp: Blueprint, futures: Sequence[Tuple[Any, ...]]

sanic/mixins/routes.py

@@ -958,6 +958,7 @@ class RouteMixin(metaclass=SanicMeta):
         # serve from the folder
         if not static.resource_type:
             if not path.isfile(file_or_directory):
+                uri = uri.rstrip("/")
                 uri += "/<__file_uri__:path>"
         elif static.resource_type == "dir":
             if path.isfile(file_or_directory):
@@ -965,6 +966,7 @@ class RouteMixin(metaclass=SanicMeta):
                     "Resource type improperly identified as directory. "
                     f"'{file_or_directory}'"
                 )
+            uri = uri.rstrip("/")
             uri += "/<__file_uri__:path>"
         elif static.resource_type == "file" and not path.isfile(
             file_or_directory