* [Better with `Annotated`](https://fastapi.tiangolo.com/tutorial/path-params-numeric-validations/#better-with-annotated)
    * [Dependencies - First Steps - Share `Annotated` dependencies](https://fastapi.tiangolo.com/tutorial/dependencies/#share-annotated-dependencies)

This is very useful when you need to:

* Have shared logic (the same code logic again and again).
* Share database connections.
* Enforce security, authentication, role requirements, etc.
* And many other things...

All these, while minimizing code repetition.

## First Steps

                    <mxGeometry x="140" y="430" width="360" height="100" as="geometry"/>
                </mxCell>

                </mxCell>
                <mxCell id="32" value="" style="pointerEvents=1;shadow=0;dashed=0;html=1;fillColor=#505050;labelPosition=center;verticalLabelPosition=bottom;verticalAlign=top;outlineConnect=0;align=center;shape=mxgraph.office.devices.laptop;strokeColor=none;" parent="33" vertex="1">
                    <mxGeometry width="500" height="350" as="geometry"/>
                </mxCell>

# Copyright (c) 2016-2023 Martin Donath <******@****.***>

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is

## Create a Pull Request

You can [contribute](contributing.md){.internal-link target=_blank} to the source code with Pull Requests, for example:

* To fix a typo you found on the documentation.
* To share an article, video, or podcast you created or found about FastAPI by <a href="https://github.com/tiangolo/fastapi/edit/master/docs/en/data/external_links.yml" class="external-link" target="_blank">editing this file</a>.

                </mxCell>
                <mxCell id="32" value="" style="pointerEvents=1;shadow=0;dashed=0;html=1;fillColor=#505050;labelPosition=center;verticalLabelPosition=bottom;verticalAlign=top;outlineConnect=0;align=center;shape=mxgraph.office.devices.laptop;strokeColor=none;" parent="33" vertex="1">
                    <mxGeometry width="500" height="350" as="geometry"/>
                </mxCell>

* Un **<abbr title="aussi connu sous le nom de composants, ressources, fournisseurs, services, injectables">système d'injection de dépendance </abbr>** très puissant et facile à utiliser .
* Sécurité et authentification, y compris la prise en charge de **OAuth2** avec les **<abbr title="en anglais : JWT tokens">jetons <abbr title="JSON Web Tokens">JWT</abbr></abbr>** et l'authentification **HTTP Basic**.

Vous pouvez ensuite continuer avec les instructions précédentes, pour une "langue existante".

##### Nouvelle langue non prise en charge

Si, lors de l'exécution du script du serveur en direct, vous obtenez une erreur indiquant que la langue n'est pas prise en charge, quelque chose comme :

```
 raise TemplateNotFound(template)
jinja2.exceptions.TemplateNotFound: partials/language/xx.html
```

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="105  107-115"
    {!> ../../../docs_src/security/tutorial005.py!}
    ```

## Verify the `username` and data shape

We verify that we get a `username`, and extract the scopes.