Extract the document updating logic into a util

src/api/categories.py

@@ -11,7 +11,7 @@ from src.api.auth.dependencies import LoggedInDep
 from src.db.models.category import Category
 from src.db.models.event import Event
 from src.db.models.user import User
-from src.utils.db import MissingIdError
+from src.utils.db import MissingIdError, update_document
 from src.utils.logging import get_logger
 
 from .auth import CurrentUserDep
@@ -74,18 +74,11 @@ class CategoryCreateData(_BaseCategoryData):
 
     async def update_category(self, category: Category) -> Category:
         """Update an existing category, overwriting all relevant data."""
-        updated = False
-
-        if category.name != self.name:
-            category.name = self.name
-            updated = True
-        if category.color != self.color:
-            category.color = self.color.as_hex(format="long")
-            updated = True
-
-        if updated:
-            category = await category.replace()
-        return category
+        return await update_document(
+            category,
+            name=self.name,
+            color=self.color.as_hex(format="long"),
+        )
 
 
 @final
@@ -100,18 +93,12 @@ class PartialCategoryUpdateData(_BaseCategoryData):
 
     async def update_category(self, category: Category) -> Category:
         """Update an existing category, overwriting it with data that were specified."""
-        updated = False
-
-        if self.name and category.name != self.name:
-            category.name = self.name
-            updated = True
-        if self.color and category.color != self.color:
-            category.color = self.color.as_hex(format="long")
-            updated = True
-
-        if updated:
-            category = await category.replace()
-        return category
+        update_dct = {}
+        if self.name is not None:
+            update_dct["name"] = self.name
+        if self.color is not None:
+            update_dct["color"] = self.color.as_hex(format="long")
+        return await update_document(category, **update_dct)
 
 
 @base_router.get("/users/{user_id}/categories")

src/api/users.py

@@ -10,7 +10,7 @@ from src.api.auth.dependencies import LoggedInDep
 from src.api.auth.passwords import check_hashed_password, create_password_hash
 from src.db.models.token import Token
 from src.db.models.user import User
-from src.utils.db import MissingIdError
+from src.utils.db import MissingIdError, update_document
 from src.utils.logging import get_logger
 
 from .auth import CurrentUserDep
@@ -69,28 +69,22 @@ class UserUpdatable(BaseModel):
     password: Annotated[str, StringConstraints(min_length=1, max_length=50)] | None = None
     email: EmailStr | None = None
 
-    async def update_user(self, user: User) -> tuple[bool, User]:
-        """Update the user with data from this instance.
+    async def update_user(self, user: User) -> User:
+        """Update the user with data from this instance."""
+        update_dct: dict[str, object] = {}
 
-        :return: Was the user updated?
-        """
-        updated = False
-        if self.username and self.username != user.username:
-            user.username = self.username
-            updated = True
-
-        if self.email and self.email != user.email:
-            user.email = self.email
-            updated = True
+        if self.username:
+            update_dct["username"] = self.username
+        if self.email:
+            update_dct["email"] = self.email
 
+        # Password is a special case, as it requires a hash check
+        # (new hash will be different even if the plain-text matches due to salting
+        # so to avoid unnecessary updates we check the hash first)
         if self.password and check_hashed_password(self.password, user.password_hash):
-            user.password_hash = create_password_hash(self.password)
-            updated = True
+            update_dct["password_hash"] = create_password_hash(self.password)
 
-        if updated:
-            user = await user.replace()
-
-        return updated, user
+        return await update_document(user, **update_dct)
 
 
 @public_router.post("")
@@ -159,7 +153,7 @@ async def patch_user(
             detail="You're not authorized to update this user",
         )
 
-    _, user = await data.update_user(user)
+    user = await data.update_user(user)
 
     return UserData.from_user(user)
 

src/utils/db.py

@@ -85,3 +85,19 @@ async def from_id_list[T: Document](
             continue
         items.append(item)
     return items
+
+
+async def update_document[T: Document](document: T, **kwargs) -> T:
+    """Update a document with given fields.
+
+    This function will only update the document if at least one of the fields differs.
+    """
+    updated = False
+    for field_name, new_value in kwargs.items():
+        old_value = getattr(document, field_name)
+        if old_value != new_value:
+            setattr(document, field_name, new_value)
+            updated = True
+    if updated:
+        document = await document.replace()
+    return document