app = SomeASGIApp()

new_app = UnicornMiddleware(app, 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")
```

```Python
from unicorn import UnicornMiddleware

app = SomeASGIApp()

new_app = UnicornMiddleware(app, some_config="rainbow")
```

```Python
from unicorn import UnicornMiddleware

app = SomeASGIApp()

new_app = UnicornMiddleware(app, some_config="rainbow")
```

Aber FastAPI (eigentlich Starlette) bietet eine einfachere Möglichkeit, welche sicherstellt, dass die internen Middlewares zur Behandlung von Serverfehlern und benutzerdefinierten Exceptionhandlern ordnungsgemäß funktionieren.

@app.exception_handler(UnicornException)
async def unicorn_exception_handler(request: Request, exc: UnicornException):
    return JSONResponse(
        status_code=418,
        content={"message": f"Oops! {exc.name} did something. There goes a rainbow..."},
    )


@app.get("/unicorns/{name}")
async def read_unicorn(name: str):
    if name == "yolo":
        raise UnicornException(name=name)

app = SomeASGIApp()

new_app = UnicornMiddleware(app, 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。

```Python
from unicorn import UnicornMiddleware

app = SomeASGIApp()

new_app = UnicornMiddleware(app, some_config="rainbow")
```

But FastAPI (actually Starlette) provides a simpler way to do it that makes sure that the internal middlewares handle server errors and custom exception handlers work properly.

def test_get_exception():
    response = client.get("/unicorns/yolo")
    assert response.status_code == 418, response.text
    assert response.json() == {
        "message": "Oops! yolo did something. There goes a rainbow..."
    }


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",

✋️ ⚫️ 🔜 🍵 `unicorn_exception_handler`.

, 👆 🔜 📨 🧹 ❌, ⏮️ 🇺🇸🔍 👔 📟 `418` & 🎻 🎚:

```JSON
{"message": "Oops! yolo did something. There goes a rainbow..."}
```

/// note | "📡 ℹ"

👆 💪 ⚙️ `from starlette.requests import Request` & `from starlette.responses import JSONResponse`.

Но оно будет обработано `unicorn_exception_handler`.

Таким образом, вы получите чистую ошибку с кодом состояния HTTP `418` и содержимым JSON:

```JSON
{"message": "Oops! yolo did something. There goes a rainbow..."}
```

/// note | "Технические детали"

Также можно использовать `from starlette.requests import Request` и `from starlette.responses import JSONResponse`.

But it will be handled by the `unicorn_exception_handler`.

So, you will receive a clean error, with an HTTP status code of `418` and a JSON content of:

```JSON
{"message": "Oops! yolo did something. There goes a rainbow..."}
```

/// note | "Technical Details"

You could also use `from starlette.requests import Request` and `from starlette.responses import JSONResponse`.