* <a href="https://github.com/tiangolo/full-stack" class="external-link" target="_blank">https://github.com/tiangolo/full-stack</a>
* <a href="https://github.com/tiangolo/full-stack-flask-couchbase" class="external-link" target="_blank">https://github.com/tiangolo/full-stack-flask-couchbase</a>

```Python hl_lines="2  6"
{!../../../docs_src/advanced_middleware/tutorial001.py!}
```

## `TrustedHostMiddleware`

Enforces that all incoming requests have a correctly set `Host` header, in order to guard against HTTP Host Header attacks.

```Python hl_lines="2  6-8"
{!../../../docs_src/advanced_middleware/tutorial002.py!}
```

The following arguments are supported:

* **👸**
* **✳**
* **🇸🇲**
* **✳**, ♒️.

!!! tip
    📤 🛂 🏗 🚂 ⏮️ **FastAPI** &amp; **🗄**, 🌐 ⚓️ 🔛 **☁**, 🔌 🕸 &amp; 🌖 🧰: <a href="https://github.com/tiangolo/full-stack-fastapi-couchbase" class="external-link" target="_blank">https://github.com/tiangolo/full-stack-fastapi-couchbase</a>

## 🗄 🗄 🦲

🔜, 🚫 💸 🙋 🎂, 🕴 🗄:

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

* Then it returns the **response**.

!!! note "Technical Details"
    If you have dependencies with `yield`, the exit code will run *after* the middleware.

    If there were any background tasks (documented later), they will run *after* all the middleware.

## Create a middleware

To create a middleware you use the decorator `@app.middleware("http")` on top of a function.

The middleware function receives:

稍后，对于您的产品级别的应用程序，您可能会要使用像**PostgreSQL**这样的数据库服务器。

!!! tip
    这儿有一个**FastAPI**和**PostgreSQL**的官方项目生成器，全部基于**Docker**，包括前端和更多工具：<a href="https://github.com/tiangolo/full-stack-fastapi-postgresql" class="external-link" target="_blank">https://github.com/tiangolo/full-stack-fastapi-postgresql</a>

!!! note
    请注意，大部分代码是`SQLAlchemy`的标准代码，您可以用于任何框架。FastAPI特定的代码和往常一样少。

## ORMs（对象关系映射）

**FastAPI**可与任何数据库在任何样式的库中一起与 数据库进行通信。

* Hỗ trợ **WebSocket**.
* In-process background tasks.
* Startup and shutdown events.
* Client cho kiểm thử xây dựng trên HTTPX.
* **CORS**, GZip, Static Files, Streaming responses.
* Hỗ trợ **Session and Cookie**.
* 100% test coverage.
* 100% type annotated codebase.

Usando essa combinação levou a criação de vários geradores Flask _full-stack_. Há muitas _stacks_ que eu (e vários times externos) estou utilizando até agora:

* <a href="https://github.com/tiangolo/full-stack" class="external-link" target="_blank">https://github.com/tiangolo/full-stack</a>

    ```Python hl_lines="13  15  22  25"
    {!> ../../../docs_src/background_tasks/tutorial002_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="13  15  22  25"
    {!> ../../../docs_src/background_tasks/tutorial002_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="14  16  23  26"
    {!> ../../../docs_src/background_tasks/tutorial002_an.py!}
    ```

=== "Python 3.10+ nicht annotiert"

```Python hl_lines="6-9"
{!../../../docs_src/background_tasks/tutorial001.py!}
```

## Adicionar a tarefa em segundo plano

Dentro de sua _função de operação de caminho_, passe sua função de tarefa para o objeto _tarefas em segundo plano_ com o método `.add_task()`:

```Python hl_lines="14"
{!../../../docs_src/background_tasks/tutorial001.py!}
```

`.add_task()` recebe como argumentos:

        self.websocket_param_name = websocket_param_name
        self.http_connection_param_name = http_connection_param_name
        self.response_param_name = response_param_name
        self.background_tasks_param_name = background_tasks_param_name
        self.security_scopes = security_scopes
        self.security_scopes_param_name = security_scopes_param_name
        self.name = name
        self.call = call
        self.use_cache = use_cache