client ->> dep: Startet den Request
    Note over dep: Führt den Code bis zum yield aus
    opt Löst Exception aus
        dep -->> handler: Löst Exception aus
        handler -->> client: HTTP-Error-Response
    end
    dep ->> operation: Führt Abhängigkeit aus, z. B. DB-Session
    opt Löst aus
        operation -->> dep: Löst Exception aus (z. B. HTTPException)
        opt Handhabt

Sie könnten einen benutzerdefinierten Exceptionhandler mittels `@app.exception_handler()` hinzufügen:

```Python hl_lines="5-7  13-18  24"
{!../../../docs_src/handling_errors/tutorial003.py!}
```

Wenn Sie nun `/unicorns/yolo` anfragen, `raise`d die *Pfadoperation* eine `UnicornException`.

Aber diese wird von `unicorn_exception_handler` gehandhabt.

!!! note "Hinweis Deutsche Übersetzung"

@asynccontextmanager
async def contextmanager_in_threadpool(
    cm: ContextManager[_T],
) -> AsyncGenerator[_T, None]:
    # blocking __exit__ from running waiting on a free thread
    # can create race conditions/deadlocks if the context manager itself
    # has its own internal pool (e.g. a database connection pool)
    # to avoid this we let __exit__ run without a capacity limit
    # since we're creating a new limiter for each call, any non-zero limit

**FastAPI**には、絶えず成長している素晴らしいコミュニティがあります。

**FastAPI**に関連する投稿、記事、ツール、およびプロジェクトは多数あります。

それらの不完全なリストを以下に示します。

!!! tip "豆知識"
    ここにまだ載っていない**FastAPI**に関連する記事、プロジェクト、ツールなどがある場合は、 <a href="https://github.com/tiangolo/fastapi/edit/master/docs/en/data/external_links.yml" class="external-link" target="_blank">プルリクエストして下さい</a>。

{% for section_name, section_content in external_links.items() %}

## {{ section_name }}

    Union,
)

from fastapi import routing
from fastapi.datastructures import Default, DefaultPlaceholder
from fastapi.exception_handlers import (
    http_exception_handler,
    request_validation_exception_handler,
    websocket_request_validation_exception_handler,
)
from fastapi.exceptions import RequestValidationError, WebSocketRequestValidationError
from fastapi.logger import logger
from fastapi.openapi.docs import (

        @classmethod
        def __get_pydantic_json_schema__(
            cls, core_schema: CoreSchema, handler: GetJsonSchemaHandler
        ) -> JsonSchemaValue:
            return {"type": "string", "format": "email"}

        @classmethod
        def __get_pydantic_core_schema__(
            cls, source: Type[Any], handler: Callable[[Any], CoreSchema]
        ) -> CoreSchema:

Using the information above, you can use the same utility function to generate the OpenAPI schema and override each part that you need.

For example, let's add <a href="https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo" class="external-link" target="_blank">ReDoc's OpenAPI extension to include a custom logo</a>.

### Normal **FastAPI**

First, write all your **FastAPI** application as normally:

class="external-link" target="_blank">`examples`</a>, mas o OpenAPI 3.0.3 é baseado numa versão mais antiga do JSON Schema que não tinha `examples`.

Por isso, o OpenAPI 3.0.3 definiu o seu próprio <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.3.md#fixed-fields-20" class="external-link" target="_blank">`example`</a> para a versão modificada do **JSON Schema** que é usada, para o mesmo próposito (mas é apenas `example` no singular, não `examples`), e é isso que é usado pela...

Дані розраховуються щомісяця, ви можете ознайомитися з <a href="https://github.com/tiangolo/fastapi/blob/master/.github/actions/people/app/main.py" class="external-link" target="_blank">вихідним кодом тут</a>.

Тут я також підкреслюю внески спонсорів.