These docs are about to be updated. 🎉

    The current version assumes Pydantic v1.

    The new docs will include Pydantic v2 and will use <a href="https://sqlmodel.tiangolo.com/" class="external-link" target="_blank">SQLModel</a> once it is updated to use Pydantic v2 as well.

!!! warning "Deprecated"
    This tutorial is deprecated and will be removed in a future version.

    ```

The files and form fields will be uploaded as form data and you will receive the files and form fields.

And you can declare some of the files as `bytes` and some as `UploadFile`.

!!! warning

Similar to the way you can [add `dependencies` to the *path operation decorators*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, you can add them to the `FastAPI` application.

In that case, they will be applied to all the *path operations* in the application:

=== "Python 3.9+"

    ```Python hl_lines="16"
    {!> ../../../docs_src/dependencies/tutorial012_an_py39.py!}
    ```

=== "Python 3.8+"

```

By declaring a *path operation function* parameter with the type being the `Request` **FastAPI** will know to pass the `Request` in that parameter.

!!! tip
    Note that in this case, we are declaring a path parameter beside the request parameter.

    So, the path parameter will be extracted, validated, converted to the specified type and annotated with OpenAPI.

    'ignore:The loop argument is deprecated since Python 3\.8, and scheduled for removal in Python 3\.10:DeprecationWarning:asyncio',
    'ignore:starlette.middleware.wsgi is deprecated and will be removed in a future release\..*:DeprecationWarning:starlette',
    # TODO: remove after upgrading HTTPX to a version newer than 0.23.0
    # Including PR: https://github.com/encode/httpx/pull/2309

    * This will be done by sending a POST request (from *your API*) to some *external API* provided by that external developer (this is the "callback").

## The normal **FastAPI** app

Let's first see how the normal API app would look like before adding the callback.

It will have a *path operation* that will receive an `Invoice` body, and a query parameter `callback_url` that will contain the URL for the callback.

## `fastapi dev`

When you run `fastapi dev`, it will run on development mode.

By default, it will have **auto-reload** enabled, so it will automatically reload the server when you make changes to your code. This is resource intensive and could be less stable than without it, you should only use it for development.

!!! tip
    All this might not seem as useful with these simple examples.

    But you will see how useful it is in the chapters about **security**.

    ```

=== "Python 3.8+"

    ```Python hl_lines="3  17"
    {!> ../../../docs_src/path_operation_configuration/tutorial001.py!}
    ```

That status code will be used in the response and will be added to the OpenAPI schema.

!!! note "Technical Details"
    You could also use `from starlette import status`.

You will see a simple page like:

<img src="/img/tutorial/websockets/image01.png">

You can type messages in the input box, and send them:

<img src="/img/tutorial/websockets/image02.png">

And your **FastAPI** application with WebSockets will respond back:

<img src="/img/tutorial/websockets/image03.png">