"schema": {
                        "$ref": "#/components/schemas/Message"
                    }
                }
            }
        },
        "200": {
            "description": "Successful Response",
            "content": {
                "application/json": {
                    "schema": {
                        "$ref": "#/components/schemas/Item"
                    }
                }

                    "schema": {
                        "$ref": "#/components/schemas/Message"
                    }
                }
            }
        },
        "200": {
            "description": "Successful Response",
            "content": {
                "application/json": {
                    "schema": {
                        "$ref": "#/components/schemas/Item"
                    }
                }

At first, it didn't have an automatic API documentation web UI, but I knew I could add Swagger UI to it.

It had a dependency injection system. It required pre-registration of components, as other tools discussed above. But still, it was a great feature.

### Dependency Injection

FastAPI bao gồm một hệ thống <abbr title='cũng biết đến như là "components", "resources", "services", "providers"'><strong>Dependency Injection</strong></abbr> vô cùng dễ sử dụng nhưng vô cùng mạnh mẽ.

    But this example is still valid and it shows how to interact with the internal components.

We can also use this same approach to access the request body in an exception handler.

All we need to do is handle the request inside a `try`/`except` block:

```Python hl_lines="13  15"

* Come stabilire **vincoli di validazione** come `maximum_length` o `regex`.
* Un sistema di **<abbr title="detto anche components, resources, providers, services, injectables">Dependency Injection</abbr>** facile da usare e molto potente.
e potente.

**剧透警告**： 教程 - 用户指南中的内容有：

* 对来自不同地方的参数进行声明，如：**请求头**、**cookies**、**form 表单**以及**上传的文件**。
* 如何设置**校验约束**如 `maximum_length` 或者 `regex`。
* 一个强大并易于使用的 **<abbr title="也被称为 components, resources, providers, services, injectables">依赖注入</abbr>** 系统。
* 安全性和身份验证，包括通过 **JWT 令牌**和 **HTTP 基本身份认证**来支持 **OAuth2**。
* 更进阶（但同样简单）的技巧来声明 **多层嵌套 JSON 模型** （借助 Pydantic）。
* 许多额外功能（归功于 Starlette）比如：
    * **WebSockets**

## Import Couchbase components

For now, don't pay attention to the rest, only the imports:

```Python hl_lines="3-5"
{!../../../docs_src/nosql_databases/tutorial001.py!}
```

## Define a constant to use as a "document type"

- 🚀 [React](https://react.dev) for the frontend.
    - 💃 Using TypeScript, hooks, Vite, and other parts of a modern frontend stack.
    - 🎨 [Chakra UI](https://chakra-ui.com) for the frontend components.
    - 🤖 An automatically generated frontend client.
    - 🦇 Dark mode support.
- 🐋 [Docker Compose](https://www.docker.com) for development and production.
- 🔒 Secure password hashing by default.

# Dependencies

**FastAPI** has a very powerful but intuitive **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection"