### 第三步：建立一個「路徑操作」 { #step-3-create-a-path-operation }

#### 路徑 { #path }

這裡的「路徑」指的是 URL 中自第一個 `/` 以後的部分。

例如，在 URL 中：

```
https://example.com/items/foo
```

……的路徑將會是：

```
/items/foo
```

/// info

「路徑」也常被稱為「端點 endpoint」或「路由 route」。

///

在建置 API 時，「路徑」是分離「關注點」和「資源」的主要方式。

#### 操作 { #operation }

這裡的「操作」指的是 HTTP 的「方法」之一。

其中包括：

# Doğrudan Bir Response Döndürme { #return-a-response-directly }

**FastAPI** ile bir *path operation* oluşturduğunuzda, normalde ondan herhangi bir veri döndürebilirsiniz: bir `dict`, bir `list`, bir Pydantic model, bir veritabanı modeli vb.

Bir [Response Model](../tutorial/response-model.md) deklare ederseniz, FastAPI veriyi Pydantic kullanarak JSON'a serialize etmek için bunu kullanır.

        CIFSException expectedException = new CIFSException("Watch operation failed");
        when(watchHandle.watch()).thenThrow(expectedException);

        // Execute and verify
        CIFSException thrown = assertThrows(CIFSException.class, () -> {
            watchHandle.watch();
        });

        assertEquals("Watch operation failed", thrown.getMessage());
        verify(watchHandle, times(1)).watch();
    }

それらの追加レスポンスは OpenAPI スキーマに含まれ、API ドキュメントにも表示されます。

ただし、それらの追加レスポンスについては、ステータスコードとコンテンツを指定して `JSONResponse` などの `Response` を直接返す必要があります。

## `model` を使った追加レスポンス { #additional-response-with-model }

*path operation デコレータ*に `responses` パラメータを渡せます。

これは `dict` を受け取り、キーは各レスポンスのステータスコード（例: `200`）、値は各レスポンスの情報を含む別の `dict` です。

それぞれのレスポンス `dict` には、`response_model` と同様に Pydantic モデルを格納する `model` キーを含められます。

    return count(object) > 0;
  }

  /**
   * Guaranteed to throw an exception and leave the collection unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public final int add(E element, int occurrences) {

  }

  // mutators (not supported)

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  // DoNotCall wants this to be final, but we want to override it to return more specific types.

     * Calculates a MAC using the ARCFOUR-HMAC-MD5 algorithm.
     * This method implements the Microsoft variant of the Kerberos ARCFOUR-HMAC-MD5 checksum.
     *
     * @param keyusage the Kerberos key usage number for this operation
     * @param key the encryption key to use for MAC calculation
     * @param data the data to calculate the MAC for
     * @return the calculated MAC bytes

import (
	"encoding/binary"
	"fmt"
	"strings"
	"time"

	"github.com/tinylib/msgp/msgp"
	"github.com/zeebo/xxh3"
)

// Op is operation type.
//
//go:generate msgp -unexported -file=$GOFILE
//go:generate stringer -type=Op -output=msg_string.go -trimprefix=Op $GOFILE

// Op is operation type messages.
type Op uint8

// HandlerID is the ID for the handler of a specific type.
type HandlerID uint8

const (

# 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
```

/**
 * SMB1 transaction subcommand for transacting with a named pipe.
 *
 * This class implements the TRANS_TRANSACT_NAMED_PIPE transaction which
 * combines writing data to a pipe and reading the response in a single operation.
 * This is more efficient than separate write and read operations.
 */
public class TransTransactNamedPipe extends SmbComTransaction {