diff --git a/nitric/resources/buckets.py b/nitric/resources/buckets.py
index c2e2d72..2db40f1 100644
--- a/nitric/resources/buckets.py
+++ b/nitric/resources/buckets.py
@@ -22,7 +22,7 @@
 from dataclasses import dataclass
 from datetime import timedelta
 from enum import Enum
-from typing import Callable, List, Literal, Optional, Union
+from typing import Callable, List, Literal, Optional, Union, cast
 from warnings import warn
 
 import betterproto
@@ -146,20 +146,40 @@ async def delete(self):
         except GRPCError as grpc_err:
             raise exception_from_grpc_error(grpc_err) from grpc_err
 
-    async def upload_url(self, expiry: Optional[timedelta] = None):
-        """Get a temporary writable URL to this file."""
-        return await self.sign_url(mode=FileMode.WRITE, expiry=expiry)
+    async def upload_url(self, expiry: Optional[Union[timedelta, int]] = None):
+        """
+        Get a temporary writable URL to this file.
 
-    async def download_url(self, expiry: Optional[timedelta] = None):
-        """Get a temporary readable URL to this file."""
-        return await self.sign_url(mode=FileMode.READ, expiry=expiry)
+        Parameters:
 
-    async def sign_url(self, mode: FileMode = FileMode.READ, expiry: Optional[timedelta] = None):
-        """Generate a signed URL for reading or writing to a file."""
-        warn("File.sign_url() is deprecated, use upload_url() or download_url() instead", DeprecationWarning)
+        expiry (timedelta or int, optional): The expiry time for the signed URL.
+        If an integer is provided, it is treated as seconds. Default is 600 seconds.
 
+        Returns:
+        str: The signed URL.
+        """
+        return await self._sign_url(mode=FileMode.WRITE, expiry=expiry)
+
+    async def download_url(self, expiry: Optional[Union[timedelta, int]] = None):
+        """
+        Get a temporary readable URL to this file.
+
+        Parameters:
+
+        expiry (timedelta or int, optional): The expiry time for the signed URL.
+        If an integer is provided, it is treated as seconds. Default is 600 seconds.
+
+        Returns:
+        str: The signed URL.
+        """
+        return await self._sign_url(mode=FileMode.READ, expiry=expiry)
+
+    async def _sign_url(self, mode: FileMode = FileMode.READ, expiry: Optional[Union[timedelta, int]] = None):
+        """Generate a signed URL for reading or writing to a file."""
         if expiry is None:
             expiry = timedelta(seconds=600)
+        if not isinstance(expiry, timedelta):
+            expiry = timedelta(seconds=expiry)
 
         try:
             response = await self._bucket._storage_stub.pre_sign_url(  # type: ignore pylint: disable=protected-access
@@ -172,7 +192,25 @@ async def sign_url(self, mode: FileMode = FileMode.READ, expiry: Optional[timede
             raise exception_from_grpc_error(grpc_err) from grpc_err
 
 
-BucketPermission = Literal["reading", "writing", "deleting"]
+LegacyBucketPermission = Literal["reading", "writing", "deleting"]
+BucketPermission = Literal["read", "write", "delete"]
+
+legacy_perms: List[LegacyBucketPermission] = ["reading", "writing", "deleting"]
+new_perms: List[BucketPermission] = ["read", "write", "delete"]
+
+
+def check_permission(permission: Union[LegacyBucketPermission, BucketPermission]) -> BucketPermission:
+    """Check if the permission is valid and return the new permission if it is a legacy permission."""
+    if permission in legacy_perms:
+        new_perm = new_perms[legacy_perms.index(cast(LegacyBucketPermission, permission))]
+        warn(
+            f"The permission '{permission}' is deprecated. Use '{new_perm}' instead.", DeprecationWarning, stacklevel=2
+        )
+        return new_perm
+    elif permission in new_perms:
+        return cast(BucketPermission, permission)
+    else:
+        raise ValueError("Invalid permission value, must be one of 'read', 'write', or 'delete'.")
 
 
 class BucketNotificationWorkerOptions:
@@ -211,9 +249,9 @@ async def _register(self) -> None:
 
     def _perms_to_actions(self, *args: BucketPermission) -> List[Action]:
         permission_actions_map: dict[BucketPermission, List[Action]] = {
-            "reading": [Action.BucketFileGet, Action.BucketFileList],
-            "writing": [Action.BucketFilePut],
-            "deleting": [Action.BucketFileDelete],
+            "read": [Action.BucketFileGet, Action.BucketFileList],
+            "write": [Action.BucketFilePut],
+            "delete": [Action.BucketFileDelete],
         }
 
         return [action for perm in args for action in permission_actions_map[perm]]
@@ -221,9 +259,15 @@ def _perms_to_actions(self, *args: BucketPermission) -> List[Action]:
     def _to_resource_id(self) -> ResourceIdentifier:
         return ResourceIdentifier(name=self.name, type=ResourceType.Bucket)  # type:ignore
 
-    def allow(self, perm: BucketPermission, *args: BucketPermission) -> BucketRef:
+    def allow(
+        self,
+        perm: Union[LegacyBucketPermission, BucketPermission],
+        *args: Union[LegacyBucketPermission, BucketPermission],
+    ) -> BucketRef:
         """Request the required permissions for this resource."""
-        str_args = [str(perm)] + [str(permission) for permission in args]
+        all_perms: List[BucketPermission] = [check_permission(perm)] + [check_permission(p) for p in args]
+
+        str_args = [str(permission) for permission in all_perms]
         self._register_policy(*str_args)
 
         return BucketRef(self.name)