{* ../../docs_src/extending_openapi/tutorial001_py310.py hl[1,4,7:9] *}

### Generate the OpenAPI schema { #generate-the-openapi-schema }

Then, use the same utility function to generate the OpenAPI schema, inside a `custom_openapi()` function:

{* ../../docs_src/extending_openapi/tutorial001_py310.py hl[2,15:21] *}

### Modify the OpenAPI schema { #modify-the-openapi-schema }

{* ../../docs_src/dependencies/tutorial007_py310.py hl[2:4] *}

The yielded value is what is injected into *path operations* and other dependencies:

{* ../../docs_src/dependencies/tutorial007_py310.py hl[4] *}

The code following the `yield` statement is executed after the response:

{* ../../docs_src/dependencies/tutorial007_py310.py hl[5:6] *}

/// tip

You can use `async` or regular functions.

## Add regular expressions { #add-regular-expressions }

You can define a <dfn title="A regular expression, regex or regexp is a sequence of characters that define a search pattern for strings.">regular expression</dfn> `pattern` that the parameter should match:

{* ../../docs_src/query_params_str_validations/tutorial004_an_py310.py hl[11] *}

**FastAPI** supports that the same way as with plain strings:

{* ../../docs_src/path_operation_configuration/tutorial002b_py310.py hl[1,8:10,13,18] *}

## Summary and description { #summary-and-description }

You can add a `summary` and `description`:

{* ../../docs_src/path_operation_configuration/tutorial003_py310.py hl[17:18] *}

## Description from docstring { #description-from-docstring }

{* ../../docs_src/security/tutorial002_an_py310.py hl[25] *}

## 取得使用者 { #get-the-user }

`get_current_user` 會使用我們建立的（假的）工具函式，它接收一個作為 `str` 的 token，並回傳我們的 Pydantic `User` 模型：

{* ../../docs_src/security/tutorial002_an_py310.py hl[19:22,26:27] *}

## 注入目前使用者 { #inject-the-current-user }

現在我們可以在*路徑操作*中用相同的 `Depends` 來使用 `get_current_user`：

{* ../../docs_src/security/tutorial002_an_py310.py hl[31] *}

パラメータ`min_length`も追加することができます:

{* ../../docs_src/query_params_str_validations/tutorial003_an_py310.py hl[10] *}

## 正規表現の追加 { #add-regular-expressions }

パラメータが一致するべき <dfn title="正規表現、regex、regexp は、文字列に対する検索パターンを定義する文字の並びです。">正規表現</dfn> `pattern` を定義することができます:

{* ../../docs_src/query_params_str_validations/tutorial004_an_py310.py hl[11] *}

この特定の正規表現パターンは受け取ったパラメータの値をチェックします:

* `^`: は、これ以降の文字で始まり、これより以前には文字はありません。

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[3] *}

## Declare `Header` parameters { #declare-header-parameters }

Then declare the header parameters using the same structure as with `Path`, `Query` and `Cookie`.

You can define the default value as well as all the extra validation or annotation parameters:

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[9] *}

/// note | Technical Details

{* ../../docs_src/path_params/tutorial001_py310.py hl[6:7] *}

路径参数 `item_id` 的值会作为参数 `item_id` 传递给你的函数。

运行示例并访问 [http://127.0.0.1:8000/items/foo](http://127.0.0.1:8000/items/foo)，可获得如下响应：

```JSON
{"item_id":"foo"}
```

## 声明路径参数的类型 { #path-parameters-with-types }

使用 Python 标准类型注解，声明路径操作函数中路径参数的类型：

{* ../../docs_src/path_params/tutorial002_py310.py hl[7] *}

本例把 `item_id` 的类型声明为 `int`。

/// check | 检查

{* ../../docs_src/path_params_numeric_validations/tutorial002_py310.py hl[7] *}

But keep in mind that if you use `Annotated`, you won't have this problem, it won't matter as you're not using the function parameter default values for `Query()` or `Path()`.

{* ../../docs_src/path_params_numeric_validations/tutorial002_an_py310.py *}

## Order the parameters as you need, tricks { #order-the-parameters-as-you-need-tricks }

{* ../../docs_src/background_tasks/tutorial001_py310.py hl[6:9] *}

## Add the background task { #add-the-background-task }

Inside of your *path operation function*, pass your task function to the *background tasks* object with the method `.add_task()`:

{* ../../docs_src/background_tasks/tutorial001_py310.py hl[14] *}

`.add_task()` receives as arguments: