Russ Cox <******@****.***> 1768661710 -0500

### Dependencies with `yield` and `except`, Technical Details { #dependencies-with-yield-and-except-technical-details }

## 含 `yield` 與 `except` 的相依 { #dependencies-with-yield-and-except }

如果你在含 `yield` 的相依中用 `except` 攔截了例外，且沒有再次拋出它（或拋出新的例外），FastAPI 將無法察覺有例外發生，就像在一般的 Python 中一樣：

{* ../../docs_src/dependencies/tutorial008c_an_py310.py hl[15:16] *}

在這種情況下，客戶端會如預期地看到一個 *HTTP 500 Internal Server Error* 回應（因為我們沒有拋出 `HTTPException` 或類似的東西），但伺服器將不會有任何日誌或其他錯誤線索。😱

/*
 * Copyright (C) 2011 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License

## Dependencies with `yield` and `except` { #dependencies-with-yield-and-except }

If you catch an exception using `except` in a dependency with `yield` and you don't raise it again (or raise a new exception), FastAPI won't be able to notice there was an exception, the same way that would happen with regular Python:

```

## `yield`, `HTTPException`, `except` 및 백그라운드 작업을 사용하는 의존성 { #dependencies-with-yield-httpexception-except-and-background-tasks }

`yield`를 사용하는 의존성은 시간이 지나면서 서로 다른 사용 사례를 다루고 일부 문제를 수정하기 위해 발전해 왔습니다.

FastAPI의 여러 버전에서 무엇이 바뀌었는지 보고 싶다면, 고급 가이드의 [고급 의존성 - `yield`, `HTTPException`, `except` 및 백그라운드 작업을 사용하는 의존성](../../advanced/advanced-dependencies.md#dependencies-with-yield-httpexception-except-and-background-tasks)에서 더 자세히 읽을 수 있습니다.

```

## 包含 `yield`、`HTTPException`、`except` 和后台任务的依赖项 { #dependencies-with-yield-httpexception-except-and-background-tasks }

带有 `yield` 的依赖项随着时间演进以涵盖不同的用例并修复了一些问题。

如果你想了解在不同 FastAPI 版本中发生了哪些变化，可以在进阶指南中阅读更多：[高级依赖项 —— 包含 `yield`、`HTTPException`、`except` 和后台任务的依赖项](../../advanced/advanced-dependencies.md#dependencies-with-yield-httpexception-except-and-background-tasks)。

## 上下文管理器 { #context-managers }

try:
    from fastapi_cli.cli import main as cli_main

except ImportError:  # pragma: no cover
    cli_main = None  # type: ignore


def main() -> None:
    if not cli_main:  # type: ignore[truthy-function]  # ty: ignore[unused-ignore-comment]
        message = 'To use the fastapi command, please install "fastapi[standard]":\n\n\tpip install "fastapi[standard]"\n'
        print(message)
        raise RuntimeError(message)  # noqa: B904

```

## `yield`、`HTTPException`、`except`、バックグラウンドタスクを持つ依存関係 { #dependencies-with-yield-httpexception-except-and-background-tasks }

`yield`を持つ依存関係は、さまざまなユースケースをカバーし、いくつかの問題を修正するために、時間とともに進化してきました。

FastAPIの異なるバージョンで何が変わったのかを知りたい場合は、上級ガイドの[上級の依存関係 - `yield`、`HTTPException`、`except`、バックグラウンドタスクを持つ依存関係](../../advanced/advanced-dependencies.md#dependencies-with-yield-httpexception-except-and-background-tasks)で詳しく読めます。

    "portal-gun": {"description": "Gun to create portals", "owner": "Rick"},
}


class OwnerError(Exception):
    pass


def get_username():
    try:
        yield "Rick"
    except OwnerError as e:
        raise HTTPException(status_code=400, detail=f"Owner error: {e}")


@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):