We are going to start from where we left in the previous chapter and increment it.

## About JWT

JWT means "JSON Web Tokens".

It's a standard to codify a JSON object in a long dense string without spaces. It looks like this:

```
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

For this example it will be super simple. But let's say that because it is shared with other projects in the organization, we cannot modify it and add a `prefix`, `dependencies`, `tags`, etc. directly to the `APIRouter`:

```Python hl_lines="3" title="app/internal/admin.py"
{!../../../docs_src/bigger_applications/app/internal/admin.py!}
```

To do that, and to accommodate different application needs, there are several ways it can do it. Some popular ways are:

* **Modify some DNS records**.
    * For this, the renewal program needs to support the APIs of the DNS provider, so, depending on the DNS provider you are using, this might or might not be an option.

But, sadly, you get nothing useful:

<img src="/img/python-types/image01.png">

### Add types

Let's modify a single line from the previous version.

We will change exactly this fragment, the parameters of the function, from:

```Python
    first_name, last_name
```

to:

```Python

    title: Inbetriebnahme eines scikit-learn-Modells mit ONNX und FastAPI
  - author: Felix Schürmeyer
    author_link: https://hellocoding.de/autor/felix-schuermeyer/
    link: https://hellocoding.de/blog/coding-language/python/fastapi
    title: REST-API Programmieren mittels Python und dem FastAPI Modul
  Japanese:
  - author: '@bee2'
    author_link: https://qiita.com/bee2

This is the same mechanism used when you give permissions while logging in with Facebook, Google, GitHub, etc:

<img src="/img/tutorial/security/image11.png">

## JWT token with scopes

Now, modify the token *path operation* to return the scopes requested.

We are still using the same `OAuth2PasswordRequestForm`. It includes a property `scopes` with a `list` of `str`, with each scope it received in the request.

### Set database state in the dependency `get_db()`

As `get_db()` is a normal `def` function, **FastAPI** will make it run in a threadpool, with a *copy* of the "context", holding the same value for the context variable (the `dict` with the reset database state). Then it can add database state to that `dict`, like the connection, etc.

![ReDoc](https://fastapi.tiangolo.com/img/index/index-02-redoc-simple.png)

## Example upgrade

Now modify the file `main.py` to receive a body from a `PUT` request.

Declare the body using standard Python types, thanks to Pydantic.

```Python hl_lines="4  9-12  25-27"
from typing import Union

Nevertheless, as this would mean waiting for the response to travel through the network while unnecessarily holding a resource in a dependency with yield (for example a database connection), this was changed in FastAPI 0.106.0.

!!! tip

```

...and adapt it with your database data and credentials (equivalently for MySQL, MariaDB or any other).

!!! tip

    This is the main line that you would have to modify if you wanted to use a different database.

### Create the SQLAlchemy `engine`

The first step is to create a SQLAlchemy "engine".

We will later use this `engine` in other places.