Or it might be the case that you just prefer to take other courses because they adapt better to your learning style.

That's what makes it possible to have multiple automatic interactive documentation interfaces, code generation, etc.

OpenAPI has a way to define multiple security "schemes".

By using them, you can take advantage of all these standard-based tools, including these interactive documentation systems.

OpenAPI defines the following security schemes:

* `apiKey`: an application specific key that can come from:

## Instalacja

<div class="termy">

```console
$ pip install fastapi

---> 100%
```

</div>

Na serwerze produkcyjnym będziesz także potrzebował serwera ASGI, np. <a href="https://www.uvicorn.org" class="external-link" target="_blank">Uvicorn</a> lub <a href="https://gitlab.com/pgjones/hypercorn" class="external-link" target="_blank">Hypercorn</a>.

But this way we can focus on how the **Dependency Injection** system works.

### Create a dependency, or "dependable"

Let's first focus on the dependency.

It is just a function that can take all the same parameters that a *path operation function* can take:

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="8-11"

You will see the JSON response as:

```JSON
{"item_id": 5, "q": "somequery"}
```

You already created an API that:

* Receives HTTP requests in the _paths_ `/` and `/items/{item_id}`.
* Both _paths_ take `GET` operations (also known as HTTP _methods_).
* The _path_ `/items/{item_id}` has a _path parameter_ `item_id` that should be an `int`.
* The _path_ `/items/{item_id}` has an optional `str` _query parameter_ `q`.

# 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.

**BARDZO zalecamy** pisanie bądź kopiowanie kodu, edycję, a następnie wykonywanie go lokalnie.

Użycie w Twoim edytorze jest tym, co pokazuje prawdziwe korzyści z FastAPI, pozwala zobaczyć jak mało kodu musisz napisać, wszystkie funkcje, takie jak kontrola typów, <abbr title="auto-complete, autocompletion, IntelliSense">automatyczne uzupełnianie</abbr>, itd.

---

## Instalacja FastAPI

Jako pierwszy krok zainstaluj FastAPI.