It's common that each authentication provider names their flows in a different way, to make it part of their brand.

But in the end, they are implementing the same OAuth2 standard.

///

**FastAPI** includes utilities for all these OAuth2 authentication flows in `fastapi.security.oauth2`.

## `Security` in decorator `dependencies`

/**
 * Manages multiple ArtifactTransformation instances and applies them in succession.
 */
@Deprecated
public interface ArtifactTransformationManager {
    String ROLE = ArtifactTransformationManager.class.getName();

    /**
     * Take in an artifact and return the transformed artifact for locating in the remote repository. If no
     * transformation has occurred the original artifact is returned.
     *

# Additional Responses in OpenAPI

/// warning

This is a rather advanced topic.

If you are starting with **FastAPI**, you might not need this.

///

You can declare additional responses, with additional status codes, media types, descriptions, etc.

Those additional responses will be included in the OpenAPI schema, so they will also appear in the API docs.

# Custom Request and APIRoute class

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.

///

And they send a request with a username `johndoe` and a password `love123`.

Then the Python code in your application would be equivalent to something like:

```Python
if "johndoe" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

    # via -r ci/official/requirements_updater/requirements.in

# The following packages are considered to be unsafe in a requirements file:
setuptools==70.0.0 \
    --hash=sha256:54faa7f2e8d2d11bcd2c07bed282eef1046b5c080d1c32add737d7b5817b1ad4 \
    --hash=sha256:f211a66637b8fa059bb28183da127d4e86396c991a942b028c6650d4319c3fd0
    # via
    #   -r ci/official/requirements_updater/requirements.in

    # via -r ci/official/requirements_updater/requirements.in
astunparse==1.6.3 \
    --hash=sha256:5ad93a8456f0d084c3456d059fd9a92cce667963232cbf763eac3bc5b7940872 \
    --hash=sha256:c2652417f2c8b5bb325c885ae329bdf3f86424075c4fd1a128674bc6fba4b8e8
    # via -r ci/official/requirements_updater/requirements.in
certifi==2024.7.4 \
    --hash=sha256:5a1e7645bc0ec61a09e26c36f6106dd4cf40c6db3a1fb6352b0244e7fb057c7b \

    # via -r ci/official/requirements_updater/requirements.in

# The following packages are considered to be unsafe in a requirements file:
setuptools==70.0.0 \
    --hash=sha256:54faa7f2e8d2d11bcd2c07bed282eef1046b5c080d1c32add737d7b5817b1ad4 \
    --hash=sha256:f211a66637b8fa059bb28183da127d4e86396c991a942b028c6650d4319c3fd0
    # via
    #   -r ci/official/requirements_updater/requirements.in

## Parameterize the instance

And now, we can use `__init__` to declare the parameters of the instance that we can use to "parameterize" the dependency:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[9] *}

In this case, **FastAPI** won't ever touch or care about `__init__`, we will use it directly in our code.

## Create an instance

This is normally called a **webhook**.

## Webhooks steps

The process normally is that **you define** in your code what is the message that you will send, the **body of the request**.

You also define in some way at which **moments** your app will send those requests or events.

And **your users** define in some way (for example in a web dashboard somewhere) the **URL** where your app should send those requests.