Il effectue également la validation des données (même imbriquées les unes dans les autres), et permet de les documenter correctement (schéma OpenAPI et documentation auto-générée).

## Valeurs scalaires dans le body

So, the frontend (that runs in the browser) would try to reach `/openapi.json` and wouldn't be able to get the OpenAPI schema.

Because we have a proxy with a path prefix of `/api/v1` for our app, the frontend needs to fetch the OpenAPI schema at `/api/v1/openapi.json`.

```mermaid
graph LR

package schema

import (
	"crypto/sha1"
	"encoding/hex"
	"regexp"
	"strings"
	"unicode/utf8"

	"github.com/jinzhu/inflection"
	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

// Namer namer interface
type Namer interface {
	TableName(table string) string
	SchemaName(table string) string
	ColumnName(table, column string) string
	JoinTableName(joinTable string) string
	RelationshipFKName(Relationship) string

Der beste Ansatz bestand außerdem darin, bereits bestehende Standards zu nutzen.

Bevor ich also überhaupt angefangen habe, **FastAPI** zu schreiben, habe ich mehrere Monate damit verbracht, die Spezifikationen für OpenAPI, JSON Schema, OAuth2, usw. zu studieren und deren Beziehungen, Überschneidungen und Unterschiede zu verstehen.

## Design { #design }

                "get": {
                    "responses": {
                        "200": {
                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "x-aperture-labs-portal": "blue",

        },
    }


@app.post(
    "/items/",
    openapi_extra={
        "requestBody": {
            "content": {
                "application/json": {
                    "schema": {
                        "required": ["name", "price"],
                        "type": "object",
                        "properties": {
                            "name": {"type": "string"},

* Documentación automática de modelos de datos con <a href="https://json-schema.org/" class="external-link" target="_blank"><strong>JSON Schema</strong></a> (ya que OpenAPI en sí mismo está basado en JSON Schema).
* Diseñado alrededor de estos estándares, tras un estudio meticuloso. En lugar de ser una capa adicional.

                    "responses": {
                        "200": {
                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                }
            }
        },
        "servers": [{"url": "/api/v1"}],

                "get": {
                    "responses": {
                        "200": {
                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Items",
                    "operationId": "read_items",
                }
            }
        },

注意，模型属性的类型、默认值及 `Field` 的代码结构与*路径操作函数*的参数相同，只不过是用 `Field` 替换了`Path`、`Query`、`Body`。

///

## 添加更多信息

`Field`、`Query`、`Body` 等对象里可以声明更多信息，并且 JSON Schema 中也会集成这些信息。

*声明示例*一章中将详细介绍添加更多信息的知识。

## 小结

Pydantic 的 `Field` 可以为模型属性声明更多校验和元数据。