Wenn Sie dieses Beispiel ausführen und auf <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a> gehen, sehen Sie als Response:

```JSON
{"item_id":"foo"}
```

## Pfad-Parameter mit Typen

Sie können den Typ eines Pfad-Parameters in der Argumentliste der Funktion deklarieren, mit Standard-Python-Typannotationen:

from fastapi import FastAPI
from fastapi.responses import StreamingResponse

some_file_path = "large-video-file.mp4"
app = FastAPI()


@app.get("/")
def main():
    def iterfile():  # (1)
        with open(some_file_path, mode="rb") as file_like:  # (2)
            yield from file_like  # (3)

pkg net/http, method (*Request) Context() context.Context
pkg net/http, method (*Request) WithContext(context.Context) *Request
pkg net/http, type Request struct, Response *Response
pkg net/http, type Response struct, Uncompressed bool
pkg net/http, type Transport struct, DialContext func(context.Context, string, string) (net.Conn, error)
pkg net/http, type Transport struct, IdleConnTimeout time.Duration

						errOnce.Do(func() {
							retError = err.Error()
						})
					}
					uploadsCancel()
					return
				}
				response := time.Since(t)
				atomic.AddUint64(&totalBytesWritten, uint64(info.Size))
				objCountPerThread[i]++
				mu.Lock()
				uploadTimes = append(uploadTimes, response)
				mu.Unlock()
			}
		}(i)
	}
	wg.Wait()

	// We already saw write failures, no need to proceed into read's

import org.lastaflute.web.api.ApiFailureHook;
import org.lastaflute.web.api.ApiFailureResource;
import org.lastaflute.web.login.exception.LoginUnauthorizedException;
import org.lastaflute.web.response.ApiResponse;
import org.lastaflute.web.response.JsonResponse;

/**
 * @author jflute
 */
public class FessApiFailureHook implements ApiFailureHook { // #change_it for handling API failure

```

////

👆 🔜 📨, 📣, `list` `bytes` ⚖️ `UploadFile`Ⓜ.

/// note | "📡 ℹ"

👆 💪 ⚙️ `from starlette.responses import HTMLResponse`.

**FastAPI** 🚚 🎏 `starlette.responses` `fastapi.responses` 🏪 👆, 👩‍💻. ✋️ 🌅 💪 📨 👟 🔗 ⚪️➡️ 💃.

///

### 💗 📁 📂 ⏮️ 🌖 🗃

& 🎏 🌌 ⏭, 👆 💪 ⚙️ `File()` ⚒ 🌖 🔢, `UploadFile`:

//// tab | 🐍 3️⃣.6️⃣ & 🔛

# Background Tasks - `BackgroundTasks`

You can declare a parameter in a *path operation function* or dependency function with the type `BackgroundTasks`, and then you can use it to schedule the execution of background tasks after the response is sent.

You can import it directly from `fastapi`:

```python
from fastapi import BackgroundTasks
```

		response.DecryptionErr = "The generated and the decrypted data key do not match"
		resp, err := json.Marshal(response)
		if err != nil {
			writeCustomErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInternalError), err.Error(), r.URL)
			return
		}
		writeSuccessResponseJSON(w, resp)
		return
	}

	resp, err := json.Marshal(response)
	if err != nil {

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

/// note | "技術詳細"

また、`from starlette.requests import Request`と`from starlette.responses import JSONResponse`を使用することもできます。

**FastAPI** は開発者の利便性を考慮して、`fastapi.responses`と同じ`starlette.responses`を提供しています。しかし、利用可能なレスポンスのほとんどはStarletteから直接提供されます。これは`Request`と同じです。

///

## デフォルトの例外ハンドラのオーバーライド

**FastAPI** にはいくつかのデフォルトの例外ハンドラがあります。

    .build();

// Connect 'em all together. Certificates are exchanged in the handshake.
Call call = client.newCall(new Request.Builder()
    .url(server.url("/"))
    .build());
Response response = call.execute();
System.out.println(response.handshake().peerPrincipal());
RecordedRequest recordedRequest = server.takeRequest();
System.out.println(recordedRequest.getHandshake().peerPrincipal());
```