"schema": {
                                        "$ref": "#/components/schemas/HTTPValidationError"
                                    }
                                }
                            },
                        },
                    },
                },
            },
        },
        "components": {
            "schemas": {
                "HTTPValidationError": {

### OpenAPI

**FastAPI** 使用定義 API 的 **OpenAPI** 標準來生成一個 「schema」 與你的所有 API。

#### 「Schema」

「schema」是對某個事物的定義或描述。它並不是實作它的程式碼，而僅僅是一個抽象的描述。

#### API 「schema」

在這種情況下，<a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank">OpenAPI</a> 是一個規範，它規定了如何定義 API 的 schema。

這個 schema 定義包含了你的 API 路徑、可能接收的參數等內容。

#### 資料 「schema」

「schema」這個術語也可能指某些資料的結構，比如 JSON 內容的結構。

                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {
                                        "$ref": "#/components/schemas/HTTPValidationError"

### Das OpenAPI-Schema generieren { #generate-the-openapi-schema }

Verwenden Sie dann dieselbe Hilfsfunktion, um das OpenAPI-Schema innerhalb einer `custom_openapi()`-Funktion zu generieren:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[2,15:21] *}

### Das OpenAPI-Schema ändern { #modify-the-openapi-schema }

                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {
                                        "$ref": "#/components/schemas/HTTPValidationError"

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[22:24] *}

### Cache the OpenAPI schema { #cache-the-openapi-schema }

You can use the property `.openapi_schema` as a "cache", to store your generated schema.

That way, your application won't have to generate the schema every time a user opens your API docs.

It will be generated only once, and then the same cached schema will be used for the next requests.

                                "application/json": {
                                    "schema": {
                                        "oneOf": [
                                            {"$ref": "#/components/schemas/FirstItem"},
                                            {"$ref": "#/components/schemas/OtherItem"},
                                        ],
                                        "discriminator": {

                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {
                                        "$ref": "#/components/schemas/HTTPValidationError"

                                "description": "Successful Response",
                                "content": {
                                    "application/json": {
                                        "schema": {"$ref": "#/components/schemas/Token"}
                                    }
                                },
                            },
                            "422": {

                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {
                                        "$ref": "#/components/schemas/HTTPValidationError"