"""
            The OpenAPI URL that Swagger UI should load and use.

            This is normally done automatically by FastAPI using the default URL
            `/openapi.json`.
            """
        ),
    ],
    title: Annotated[
        str,
        Doc(
            """
            The HTML `<title>` content, normally shown in the browser tab.
            """
        ),
    ],
    swagger_js_url: Annotated[

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 { #webhooks-steps }

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

But there are specific cases where it's useful to get the `Request` object.

* `refactor`: Refactors
    * This is normally for changes to the internal code that don't change the behavior. Normally it improves maintainability, or enables future features, etc.
* `upgrade`: Upgrades

And then you can set the `status_code` in that *temporal* response object.

{* ../../docs_src/response_change_status_code/tutorial001_py39.py hl[1,9,12] *}

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

And if you declared a `response_model`, it will still be used to filter and convert the object you returned.

# FastAPI in Containers - Docker { #fastapi-in-containers-docker }

When deploying FastAPI applications a common approach is to build a **Linux container image**. It's normally done using <a href="https://www.docker.com/" class="external-link" target="_blank">**Docker**</a>. You can then deploy that container image in one of a few possible ways.

Using Linux containers has several advantages including **security**, **replicability**, **simplicity**, and others.

/// tip

## About "Form Fields" { #about-form-fields }

The way HTML forms (`<form></form>`) sends the data to the server normally uses a "special" encoding for that data, it's different from JSON.

**FastAPI** will make sure to read that data from the right place instead of JSON.

/// note | Technical Details

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

## Security - HTTPS { #security-https }

In the [previous chapter about HTTPS](https.md){.internal-link target=_blank} we learned about how HTTPS provides encryption for your API.

We also saw that HTTPS is normally provided by a component **external** to your application server, a **TLS Termination Proxy**.

Also, HTTP headers are case-insensitive, so, you can declare them with standard Python style (also known as "snake_case").

So, you can use `user_agent` as you normally would in Python code, instead of needing to capitalize the first letters as `User_Agent` or something similar.

* `HEAD`
* `PATCH`
* `TRACE`

In the HTTP protocol, you can communicate to each path using one (or more) of these "methods".

---

When building APIs, you normally use these specific HTTP methods to perform a specific action.

Normally you use:

* `POST`: to create data.
* `GET`: to read data.
* `PUT`: to update data.
* `DELETE`: to delete data.