Dazu verwenden Sie `app.add_middleware()` (wie schon im Beispiel für CORS gesehen).

```Python
from fastapi import FastAPI
from unicorn import UnicornMiddleware

app = FastAPI()

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

```

✋️ FastAPI (🤙 💃) 🚚 🙅 🌌 ⚫️ 👈 ⚒ 💭 👈 🔗 🛠️ 🍵 💽 ❌ & 🛃 ⚠ 🐕‍🦺 👷 ☑.

👈, 👆 ⚙️ `app.add_middleware()` (🖼 ⚜).

```Python
from fastapi import FastAPI
from unicorn import UnicornMiddleware

app = FastAPI()

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

`app.add_middleware()` 📨 🛠️ 🎓 🥇 ❌ & 🙆 🌖 ❌ 🚶‍♀️ 🛠️.

## 🛠️ 🛠️

**FastAPI** 🔌 📚 🛠️ ⚠ ⚙️ 💼, 👥 🔜 👀 ⏭ ❔ ⚙️ 👫.

For that, you use `app.add_middleware()` (as in the example for CORS).

```Python
from fastapi import FastAPI
from unicorn import UnicornMiddleware

app = FastAPI()

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

```

但 FastAPI（实际上是 Starlette）提供了一种更简单的方式，能让内部中间件在处理服务器错误的同时，还能让自定义异常处理器正常运作。

为此，要使用 `app.add_middleware()` （与 CORS 中的示例一样）。

```Python
from fastapi import FastAPI
from unicorn import UnicornMiddleware

app = FastAPI()

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

`app.add_middleware()` 的第一个参数是中间件的类，其它参数则是要传递给中间件的参数。

## 集成中间件

**FastAPI** 为常见用例提供了一些中间件，下面介绍怎么使用这些中间件。

from fastapi import FastAPI
from fastapi.middleware.trustedhost import TrustedHostMiddleware

app = FastAPI()

app.add_middleware(
    TrustedHostMiddleware, allowed_hosts=["example.com", "*.example.com"]
)


@app.get("/")
async def main():

from fastapi import FastAPI
from fastapi.middleware.gzip import GZipMiddleware

app = FastAPI()

app.add_middleware(GZipMiddleware, minimum_size=1000)


@app.get("/")
async def main():

from fastapi import FastAPI
from fastapi.middleware.httpsredirect import HTTPSRedirectMiddleware

app = FastAPI()

app.add_middleware(HTTPSRedirectMiddleware)


@app.get("/")
async def main():

app = FastAPI()

origins = [
    "http://localhost.tiangolo.com",
    "https://localhost.tiangolo.com",
    "http://localhost",
    "http://localhost:8080",
]

app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.get("/")
async def main():

@router.post("/middleware")
def run_middleware(file: UploadFile = File(..., description="Big File")):
    return {"message": "OK"}


app.include_router(router)
app.add_middleware(ContentSizeLimitMiddleware, max_content_size=2**8)


client = TestClient(app)


def test_custom_middleware_exception(tmp_path: Path):
    default_pydantic_max_size = 2**16
    path = tmp_path / "test.txt"

            Doc(
                """
                List of middleware to be added when creating the application.

                In FastAPI you would normally do this with `app.add_middleware()`
                instead.

                Read more in the
                [FastAPI docs for Middleware](https://fastapi.tiangolo.com/tutorial/middleware/).
                """
            ),