from fastapi.testclient import TestClient


class CustomError(Exception):
    pass


def catching_dep() -> Any:
    try:
        yield "s"
    except CustomError as err:
        raise HTTPException(status_code=418, detail="Session error") from err


def broken_dep() -> Any:
    yield "s"
    raise ValueError("Broken after yield")


app = FastAPI()


@app.get("/catching")

        self.name = name


app = FastAPI()


@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":

app.include_router(users.router)
app.include_router(items.router)
app.include_router(
    admin.router,
    prefix="/admin",
    tags=["admin"],
    dependencies=[Depends(get_token_header)],
    responses={418: {"description": "I'm a teapot"}},
)


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

    return await request_validation_exception_handler(request, exc)


@app.get("/items/{item_id}")
async def read_item(item_id: int):
    if item_id == 3:
        raise HTTPException(status_code=418, detail="Nope! I don't like 3.")

Here, if you request `/unicorns/yolo`, the *path operation* will `raise` a `UnicornException`.

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

The result is that in our app, each of the *path operations* from the `admin` module will have:

* The prefix `/admin`.
* The tag `admin`.
* The dependency `get_token_header`.
* The response `418`. 🍵

But that will only affect that `APIRouter` in our app, not in any other code that uses it.

So, for example, other projects could use the same `APIRouter` with a different authentication method.

{* ../../docs_src/handling_errors/tutorial003_py310.py hl[5:7,13:18,24] *}

ここで、`/unicorns/yolo`をリクエストすると、*path operation*は`UnicornException`を`raise`します。

しかし、これは`unicorn_exception_handler`で処理されます。

そのため、HTTPステータスコードが`418`で、JSONの内容が以下のような明確なエラーを受け取ることになります:

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

/// note | 技術詳細

这样，原始的 `APIRouter` 将保持不变，因此我们仍然可以与组织中的其他项目共享相同的 `app/internal/admin.py` 文件。

结果是在我们的应用程序中，来自 `admin` 模块的每个*路径操作*都将具有：

* `/admin` 前缀 。
* `admin` 标签。
* `get_token_header` 依赖项。
* `418` 响应。 🍵

但这只会影响我们应用中的 `APIRouter`，而不会影响使用它的任何其他代码。

因此，举例来说，其他项目能够以不同的身份认证方法使用相同的 `APIRouter`。

### 包含一个*路径操作* { #include-a-path-operation }

我们还可以直接将*路径操作*添加到 `FastAPI` 应用中。

    return PlainTextResponse(message, status_code=400)


@app.get("/items/{item_id}")
async def read_item(item_id: int):
    if item_id == 3:
        raise HTTPException(status_code=418, detail="Nope! I don't like 3.")

                                "description": "Successful Response",
                                "content": {"application/json": {"schema": {}}},
                            },
                            "418": {"description": "I'm a teapot"},
                            "422": {
                                "description": "Validation Error",
                                "content": {