# Python Types Intro

Python has support for optional "type hints" (also called "type annotations").

These **"type hints"** or annotations are a special syntax that allow declaring the <abbr title="for example: str, int, float, bool">type</abbr> of a variable.

By declaring types for your variables, editors and tools can give you better support.

🚨 This is probably the last release (or one of the last releases) to support Python 3.6. 🔥

Python 3.6 reached the [end-of-life and is no longer supported by Python](https://www.python.org/downloads/release/python-3615/) since around a year ago.

You hopefully updated to a supported version of Python a while ago. If you haven't, you really should.

### Features

# Introduction aux Types Python

Python supporte des annotations de type (ou *type hints*) optionnelles.

Ces annotations de type constituent une syntaxe spéciale qui permet de déclarer le <abbr title="par exemple : str, int, float, bool">type</abbr> d'une variable.

En déclarant les types de vos variables, cela permet aux différents outils comme les éditeurs de texte d'offrir un meilleur support.

* <a href="https://pythonhosted.org/itsdangerous/" target="_blank"><code>itsdangerous</code></a> - Required for `SessionMiddleware` support.

!!! check "Inspired **FastAPI** to"
    Define extra validations for data types using the "default" value of model attributes. This improves editor support, and it was not available in Pydantic before.

    This actually inspired updating parts of Pydantic, to support the same validation declaration style (all this functionality is now already available in Pydantic).

エディターがどのように役立つかを以下に示します:

* <a href="https://code.visualstudio.com/" class="external-link" target="_blank">Visual Studio Code</a>の場合:

![editor support](https://fastapi.tiangolo.com/img/vscode-completion.png)

* <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a>の場合:

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

以前は不可能だと考えていたコードでさえ補完されます。例えば、リクエストからのJSONボディ（ネストされている可能性がある）内の `price`キーです。

    # to support it as a first class "feature"
    assert is_bytes_sequence_annotation(Union[List[str], List[bytes]])


def test_is_uploadfile_sequence_annotation():
    # For coverage
    # TODO: in theory this would allow declaring types that could be lists of UploadFile
    # and other types, but I'm not even sure it's a good idea to support it as a first
    # class "feature"

* <a href="https://code.visualstudio.com/" class="external-link" target="_blank">Visual Studio Code</a> ile:

![editor support](https://fastapi.tiangolo.com/img/vscode-completion.png)

* <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a> ile:

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

But you need `file_path` itself to contain a *path*, like `home/johndoe/myfile.txt`.

So, the URL for that file would be something like: `/files/home/johndoe/myfile.txt`.

### OpenAPI support

OpenAPI doesn't support a way to declare a *path parameter* to contain a *path* inside, as that could lead to scenarios that are difficult to test and define.

And an `APIRoute` subclass to use that custom request class.

### Create a custom `GzipRequest` class

!!! tip
    This is a toy example to demonstrate how it works, if you need Gzip support, you can use the provided [`GzipMiddleware`](../advanced/middleware.md#gzipmiddleware){.internal-link target=_blank}.