# JSON Compatible Encoder

There are some cases where you might need to convert a data type (like a Pydantic model) to something compatible with JSON (like a `dict`, `list`, etc).

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder`

Let's imagine that you have a database `fake_db` that only receives JSON compatible data.

* The **input model** needs to be able to have a password.
* The **output model** should not have a password.
* The **database model** would probably need to have a hashed password.

!!! danger
    Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.

    If you don't know, you will learn what a "password hash" is in the [security chapters](security/simple-oauth2.md#password-hashing){.internal-link target=_blank}.

    ```

### Использование параметра `update` в Pydantic

Теперь можно создать копию существующей модели, используя `.copy()`, и передать параметр `update` с `dict`, содержащим данные для обновления.

Например, `stored_item_model.copy(update=update_data)`:

=== "Python 3.10+"

    ```Python hl_lines="33"
    {!> ../../../docs_src/body_updates/tutorial002_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="35"

And it will save the returned value in a <abbr title="A utility/system to store computed/generated values, to re-use them instead of computing them again.">"cache"</abbr> and pass it to all the "dependants" that need it in that specific request, instead of calling the dependency multiple times for the same request.

If you have a big application, you might end up accumulating **several tags**, and you would want to make sure you always use the **same tag** for related *path operations*.

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

```Python hl_lines="1  8-10  13  18"
{!../../../docs_src/path_operation_configuration/tutorial002b.py!}
```

    * Query parameters.
    * Cookies, etc.

Plus all the security features from Starlette (including **session cookies**).

All built as reusable tools and components that are easy to integrate with your systems, data stores, relational and NoSQL databases, etc.

### Dependency Injection

    * Les cookies, etc.

Plus toutes les fonctionnalités de sécurités venant de Starlette (incluant les **cookies de sessions**).

Le tout conçu en composant réutilisable facilement intégrable à vos systèmes, data stores, base de données relationnelle ou NoSQL, etc.

### Injection de dépendances

```Python
commons: Annotated[dict, Depends(common_parameters)]
```

But because we are using `Annotated`, we can store that `Annotated` value in a variable and use it in multiple places:

=== "Python 3.10+"

    ```Python hl_lines="12  16  21"
    {!> ../../../docs_src/dependencies/tutorial001_02_an_py310.py!}
    ```

```Python hl_lines="22-24"
{!../../../docs_src/extending_openapi/tutorial001.py!}
```

### Cache the OpenAPI schema

You can use the property `.openapi_schema` as a "cache", to store your generated schema.

That way, your application won't have to generate the schema every time a user opens your API docs.

It will be generated only once, and then the same cached schema will be used for the next requests.

```

## ⚙️ 🎏 🔗 💗 🕰

🚥 1️⃣ 👆 🔗 📣 💗 🕰 🎏 *➡ 🛠️*, 🖼, 💗 🔗 ✔️ ⚠ 🎧-🔗, **FastAPI** 🔜 💭 🤙 👈 🎧-🔗 🕴 🕐 📍 📨.

&amp; ⚫️ 🔜 🖊 📨 💲 <abbr title="A utility/system to store computed/generated values, to re-use them instead of computing them again.">"💾"</abbr> &amp; 🚶‍♀️ ⚫️ 🌐 "⚓️" 👈 💪 ⚫️ 👈 🎯 📨, ↩️ 🤙 🔗 💗 🕰 🎏 📨.