from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()

    original_type = field.type_
    if is_dataclass(original_type) and hasattr(original_type, "__pydantic_model__"):
        original_type = original_type.__pydantic_model__
    use_type = original_type
    if lenient_issubclass(original_type, BaseModel):
        original_type = cast(Type[BaseModel], original_type)
        use_type = cloned_types.get(original_type)
        if use_type is None:

There are some scenarios where you might want to override a dependency during testing.

You don't want the original dependency to run (nor any of the sub-dependencies it might have).

Instead, you want to provide a different dependency that will be used only during tests (possibly only some specific tests), and will provide a value that can be used where the value of the original dependency was used.

### Use cases: external service

from fastapi.routing import APIRoute


class TimedRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            before = time.time()
            response: Response = await original_route_handler(request)
            duration = time.time() - before
            response.headers["X-Response-Time"] = str(duration)

        with:
          token: ${{ secrets.FASTAPI_ISSUE_MANAGER }}
          config: >
            {
              "answered": {
                "delay": 864000,
                "message": "Assuming the original need was handled, this will be automatically closed now. But feel free to add more comments or create new issues or PRs."
              },
              "changes-requested": {
                "delay": 2628000,

This time, it will overwrite the method `APIRoute.get_route_handler()`.

This method returns a function. And that function is what will receive a request and return a response.

Here we use it to create a `GzipRequest` from the original request.

```Python hl_lines="18-26"
{!../../../docs_src/custom_request_and_route/tutorial001.py!}
```

!!! note "Technical Details"

We can declare all that without having to modify the original `APIRouter` by passing those parameters to `app.include_router()`:

```Python hl_lines="14-17" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

            dependency_overrides_provider
            and dependency_overrides_provider.dependency_overrides
        ):
            original_call = sub_dependant.call
            call = getattr(
                dependency_overrides_provider, "dependency_overrides", {}
            ).get(original_call, original_call)
            use_path: str = sub_dependant.path  # type: ignore
            use_sub_dependant = get_dependant(

### Features

* ⚡ Update `create_cloned_field` to use a global cache and improve startup performance. PR [#4645](https://github.com/tiangolo/fastapi/pull/4645) by [@madkinsz](https://github.com/madkinsz) and previous original PR by [@huonw](https://github.com/huonw).

### Docs

### Always `raise` in Dependencies with `yield` and `except`

If you catch an exception in a dependency with `yield`, unless you are raising another `HTTPException` or similar, you should re-raise the original exception.

You can re-raise the same exception using `raise`:

=== "Python 3.9+"

    ```Python hl_lines="17"
    {!> ../../../docs_src/dependencies/tutorial008d_an_py39.py!}
    ```