# OpenAPI

There are several utilities to handle OpenAPI.

---

"_Honestly, what you've built looks super solid and polished. In many ways, it's what I wanted **Hug** to be - it's really inspiring to see someone build that._"

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"_Honestly, what you've built looks super solid and polished. In many ways, it's what I wanted **Hug** to be - it's really inspiring to see someone build that._"

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

You could still use most of the features in **FastAPI** with the knowledge from the main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank}.

And the next sections assume you already read it, and assume that you know those main ideas.

## External Courses

- <a href="https://github.com/Kludex/python-multipart" target="_blank"><code>python-multipart</code></a> - আপনি যদি ফর্ম সহায়তা করতে চান তাহলে প্রয়োজন <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>, `request.form()` সহ।
- <a href="https://pythonhosted.org/itsdangerous/" target="_blank"><code>itsdangerous</code></a> - `SessionMiddleware` সহায়তার জন্য প্রয়োজন।

# Abhängigkeiten

**FastAPI** hat ein sehr mächtiges, aber intuitives **<abbr title="Dependency Injection – Einbringen von Abhängigkeiten: Auch bekannt als Komponenten, Ressourcen, Provider, Services, Injectables">Dependency Injection</abbr>** System.

Es ist so konzipiert, sehr einfach zu verwenden zu sein und es jedem Entwickler sehr leicht zu machen, andere Komponenten mit **FastAPI** zu integrieren.

## Was ist „Dependency Injection“

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"_Honestly, what you've built looks super solid and polished. In many ways, it's what I wanted **Hug** to be - it's really inspiring to see someone build that._"

<div class="termy">

```console
$ pip install "fastapi[all]"

---> 100%
```

</div>

...that also includes `uvicorn`, that you can use as the server that runs your code.

!!! note
    You can also install it part by part.

    This is what you would probably do once you want to deploy your application to production:

    ```
    pip install fastapi
    ```

# Deployment

Deploying a **FastAPI** application is relatively easy.

## What Does Deployment Mean

To **deploy** an application means to perform the necessary steps to make it **available to the users**.

For a **web API**, it normally involves putting it in a **remote machine**, with a **server program** that provides good performance, stability, etc, so that your **users** can **access** the application efficiently and without interruptions or problems.

* For `PUT` requests to `/items/{item_id}`, Read the body as JSON:
    * Check that it has a required attribute `name` that should be a `str`.
    * Check that it has a required attribute `price` that has to be a `float`.
    * Check that it has an optional attribute `is_offer`, that should be a `bool`, if present.
    * All this would also work for deeply nested JSON objects.