{* ../../docs_src/path_operation_advanced_configuration/tutorial003_py39.py hl[6] *}

## Advanced description from docstring { #advanced-description-from-docstring }

You can limit the lines used from the docstring of a *path operation function* for OpenAPI.

Adding an `\f` (an escaped "form feed" character) causes **FastAPI** to truncate the output used for OpenAPI at this point.

## `summary` 和 `description` 参数

路径装饰器还支持 `summary` 和 `description` 这两个参数：

{* ../../docs_src/path_operation_configuration/tutorial003.py hl[20:21] *}

## 文档字符串（`docstring`）

描述内容比较长且占用多行时，可以在函数的 <abbr title="函数中作为第一个表达式，用于文档目的的一个多行字符串（并没有被分配个任何变量）">docstring</abbr> 中声明*路径操作*的描述，**FastAPI** 支持从文档字符串中读取描述内容。

    [TensorFlow Builds](https://github.com/tensorflow/tensorflow/tree/master/tensorflow/tools/ci_build)
    for details.

#### Running doctest for testable docstring

There are two ways to test the code in the docstring locally:

1.  If you are only changing the docstring of a class/function/method, then you
    can test it by passing that file's path to

{* ../../docs_src/path_operation_advanced_configuration/tutorial003.py hl[6] *}

## Description avancée de docstring

Vous pouvez limiter le texte utilisé de la docstring d'une *fonction de chemin* qui sera affiché sur OpenAPI.

L'ajout d'un `\f` (un caractère d'échappement "form feed") va permettre à **FastAPI** de tronquer la sortie utilisée pour OpenAPI à ce stade.

{* ../../docs_src/path_operation_advanced_configuration/tutorial003_py39.py hl[6] *}

## Descripción avanzada desde el docstring { #advanced-description-from-docstring }

Puedes limitar las líneas usadas del docstring de una *path operation function* para OpenAPI.

Añadir un `\f` (un carácter de separación de página escapado) hace que **FastAPI** trunque la salida usada para OpenAPI en este punto.

{* ../../docs_src/path_operation_advanced_configuration/tutorial003_py39.py hl[6] *}

## Descrição avançada a partir de docstring { #advanced-description-from-docstring }

Você pode limitar as linhas utilizadas a partir de uma docstring de uma *função de operação de rota* para o OpenAPI.

Вы можете добавить параметры `summary` и `description`:

{* ../../docs_src/path_operation_configuration/tutorial003_py310.py hl[18:19] *}

## Описание из строк документации { #description-from-docstring }

Le principe est le suivant : vous écrivez la définition du schéma au format YAML dans la docstring de chaque fonction gérant une route.

Et il génère des schémas OpenAPI.

C'est ainsi que cela fonctionne dans Flask, Starlette, Responder, etc.

Mais alors, nous avons à nouveau le problème d'avoir une micro-syntaxe, dans une docstring Python (un gros morceau de YAML).

            Optional[str],
            Doc(
                """
                A description for the *path operation*.

                If not provided, it will be extracted automatically from the docstring
                of the *path operation function*.

                It can contain Markdown.

                It will be added to the generated OpenAPI (e.g. visible at `/docs`).

It is a plug-in for many frameworks (and there's a plug-in for Starlette too).

The way it works is that you write the definition of the schema using YAML format inside the docstring of each function handling a route.

And it generates OpenAPI schemas.

That's how it works in Flask, Starlette, Responder, etc.