# Return a Response Directly { #return-a-response-directly }

When you create a **FastAPI** *path operation* you can normally return any data from it: a `dict`, a `list`, a Pydantic model, a database model, etc.

If you declare a [Response Model](../tutorial/response-model.md) FastAPI will use it to serialize the data to JSON, using Pydantic.

| *Type*     | *String* |
| *Required* | *Yes*    |

### DurationSeconds

The duration, in seconds. The value can range from 900 seconds (15 minutes) up to 365 days. If value is higher than this setting, then operation fails. By default, the value is set to 3600 seconds. If no *DurationSeconds* is specified expiry seconds is obtained from *Token*.

| Params        | Value                                              |

/// tip | 豆知識

Pydantic は **Rust** 側でシリアライズを行うため、戻り値の型を宣言しない場合に比べて大幅に高い**パフォーマンス**が得られます。

///

### 非 async の *path operation 関数* { #non-async-path-operation-functions }

`async` を使わない通常の `def` 関数でも同様に `yield` を使えます。

FastAPI が適切に実行されるように処理するため、イベントループをブロックしません。

この場合は関数が async ではないので、適切な戻り値の型は `Iterable[Item]` です:

    /**
     * Select the least busy channel based on pending operations
     */
    LEAST_LOADED,

    /**
     * Weighted random selection based on channel scores
     */
    WEIGHTED_RANDOM,

    /**
     * Affinity-based selection for related operations
     */
    AFFINITY_BASED,

    /**
     * Adaptive selection based on operation type and performance
     */
    ADAPTIVE

    return {"name": fake_items_db[item_id]["name"], "item_id": item_id}


@router.put(
    "/{item_id}",
    tags=["custom"],
    responses={403: {"description": "Operation forbidden"}},
)
async def update_item(item_id: str):
    if item_id != "plumbus":
        raise HTTPException(
            status_code=403, detail="You can only update the item: plumbus"
        )

    },
}


class EventSourceResponse(StreamingResponse):
    """Streaming response with `text/event-stream` media type.

    Use as `response_class=EventSourceResponse` on a *path operation* that uses `yield`
    to enable Server Sent Events (SSE) responses.

    Works with **any HTTP method** (`GET`, `POST`, etc.), which makes it compatible
    with protocols like MCP that stream SSE over `POST`.

   * described in the class documentation.
   *
   * @throws NullPointerException if any of {@code elements} is null
   * @since 6.0
   */
  public static <E> ImmutableMultiset<E> copyOf(E[] elements) {
    return copyFromElements(elements);
  }

  /**
   * Returns an immutable multiset containing the given elements, in the "grouped iteration order"

    "tax": 3.2
}
```

## Recap { #recap }

You can add multiple body parameters to your *path operation function*, even though a request can only have a single body.

But **FastAPI** will handle it, give you the correct data in your function, and validate and document the correct schema in the *path operation*.

You can also declare singular values to be received as part of the body.

    return this.<T>trustedPut(type.rejectTypeVariables(), value);
  }

  /**
   * Not supported. Use {@link #putInstance} instead.
   *
   * @deprecated unsupported operation
   * @throws UnsupportedOperationException always
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")

* tested (adjective): протестированный
* middleware: middleware (don't translate, but add `промежуточный слой` if clarification is needed)
* path operation: операция пути (optionally clarify as `обработчик пути`)
* path operation function: функция-обработчик пути (or `функция обработки пути`)
* proprietary: проприетарный