There have been many tools created before that have helped inspire its creation.

I have been avoiding the creation of a new framework for several years. First I tried to solve all the features covered by **FastAPI** using many different frameworks, plug-ins, and tools.

        self.call = call
        self.use_cache = use_cache
        # Store the path to be able to re-generate a dependable from it in overrides
        self.path = path
        # Save the cache key at creation to optimize performance

There have been many tools created before that have helped inspire its creation.

I have been avoiding the creation of a new framework for several years. First I tried to solve all the features covered by **FastAPI** using many different frameworks, plug-ins, and tools.

## The normal process

The normal (default) process, is as follows.

A `FastAPI` application (instance) has an `.openapi()` method that is expected to return the OpenAPI schema.

As part of the application object creation, a *path operation* for `/openapi.json` (or for whatever you set your `openapi_url`) is registered.

It just returns a JSON response with the result of the application's `.openapi()` method.

<blockquote markdown="1">

**FastAPI** n'existerait pas sans le travail antérieur d'autres personnes.

Il y a eu de nombreux outils créés auparavant qui ont contribué à inspirer sa création.

J'ai évité la création d'un nouveau framework pendant plusieurs années. J'ai d'abord essayé de résoudre toutes les fonctionnalités couvertes par **FastAPI** en utilisant de nombreux frameworks, plug-ins et outils différents.

<div style="text-align: right; margin-right: 10%;">Timothy Crosley - <strong><a href="https://www.hug.rest/" target="_blank">Hug</a> creator</strong> <a href="https://news.ycombinator.com/item?id=19455465" target="_blank"><small>(ref)</small></a></div>

---

Si vous avez une *fonction de chemin* qui reçoit un *paramètre de chemin*, mais que vous voulez que les valeurs possibles des paramètres soient prédéfinies, vous pouvez utiliser les <abbr title="Enumeration">`Enum`</abbr> de Python.

### Création d'un `Enum`

Importez `Enum` et créez une sous-classe qui hérite de `str` et `Enum`.

## FastAPI features

**FastAPI** gives you the following:

### Based on open standards

* <a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank"><strong>OpenAPI</strong></a> for API creation, including declarations of <abbr title="also known as: endpoints, routes">path</abbr> <abbr title="also known as HTTP methods, as POST, GET, PUT, DELETE">operations</abbr>, parameters, body requests, security, etc.

You can also use `response_model=None` to disable creating a response model for that *path operation*, you might need to do it if you are adding type annotations for things that are not valid Pydantic fields, you will see an example of that in one of the sections below.

You can use the same type declarations with `str`, `float`, `bool` and many other complex data types.

Several of these are explored in the next chapters of the tutorial.

## Order matters

When creating *path operations*, you can find situations where you have a fixed path.

Like `/users/me`, let's say that it's to get data about the current user.