}
	}

}

func TestReaderSize(t *testing.T) {
	if got, want := NewReader(nil).Size(), DefaultBufSize; got != want {
		t.Errorf("NewReader's Reader.Size = %d; want %d", got, want)
	}
	if got, want := NewReaderSize(nil, 1234).Size(), 1234; got != want {
		t.Errorf("NewReaderSize's Reader.Size = %d; want %d", got, want)
	}
}

You can check it at <a href="http://127.0.0.1:9999/api/v1/docs" class="external-link" target="_blank">http://127.0.0.1:9999/api/v1/docs</a>:

<img src="/img/tutorial/behind-a-proxy/image02.png">

Right as we wanted it. ✔️

This is because FastAPI uses this `root_path` to create the default `server` in OpenAPI with the URL provided by `root_path`.

## Additional servers

/// warning

* <a href="https://jinja.palletsprojects.com" target="_blank"><code>jinja2</code></a> - Required if you want to use the default template configuration.

   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  // DoNotCall wants this to be final, but we want to override it to return more specific types.
  // Inheritance is closed, and all subtypes are @DoNotCall, so this is safe to suppress.
  @SuppressWarnings("DoNotCall")

## Additional status codes

If you want to return additional status codes apart from the main one, you can do that by returning a `Response` directly, like a `JSONResponse`, and set the additional status code directly.

For example, let's say that you want to have a *path operation* that allows to update items, and returns HTTP status codes of 200 "OK" when successful.

     * @param result The artifact descriptor result, never {@code null}.
     * @param model The artifact model, never {@code null}.
     * @return The {@link Artifact} to relocate to, or {@code null} if no relocation wanted.
     */
    Artifact relocatedTarget(RepositorySystemSession session, ArtifactDescriptorResult result, Model model)
            throws ArtifactDescriptorException;

And it shows their true commitment to FastAPI and its **community** (you), as they not only want to provide you a **good service** but also want to make sure you have a **good and healthy framework**, FastAPI. 🙇

You might want to try their services and follow their guides:

All the dependencies we have seen are a fixed function or class.

But there could be cases where you want to be able to set parameters on the dependency, without having to declare many different functions or classes.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

But we want to be able to parameterize that fixed content.

## A "callable" instance

# OpenAPI Webhooks

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

## Webhooks steps

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

/// danger

This is an "advanced" feature.

If you are just starting with **FastAPI** you might want to skip this section.

///