* They need to handle cleanup (e.g., DB sessions, file handles), using dependencies with `yield`
* Their logic needs input data from the request, like headers, query parameters, etc.

## Dependencies with `yield` and `scope`

When using dependencies with `yield`, they can have a `scope` that defines when the exit code is run.

# Response Header'ları { #response-headers }

## Bir `Response` parametresi kullanın { #use-a-response-parameter }

*Path operation function* içinde (cookie'lerde yapabildiğiniz gibi) tipi `Response` olan bir parametre tanımlayabilirsiniz.

Sonra da bu *geçici* response nesnesi üzerinde header'ları ayarlayabilirsiniz.

{* ../../docs_src/response_headers/tutorial002_py310.py hl[1, 7:8] *}

OpenAPI также добавила поля `example` и `examples` в другие части спецификации:

* [`Parameter Object` (в спецификации)](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#parameter-object), которое использовалось в FastAPI:
    * `Path()`
    * `Query()`
    * `Header()`
    * `Cookie()`

        final AtomicReference<JobLog> storedJobLog = new AtomicReference<>();

        registerComponents(scheduledJob, storedJobLog);

        // Create runtime with JOB_LOG_ID parameter
        final Map<String, Object> params = new HashMap<>();
        params.put(Constants.SCHEDULED_JOB, scheduledJob);
        params.put(Constants.JOB_LOG_ID, "pregenerated-abc123");

     * implemented. A <code>scope</code> of <code>null</code> or <code>""</code>
     * signifies no scope.
     *
     * The additional <code>svr</code> parameter specifies the address to
     * query. This might be the address of a specific host, a name server,
     * or a broadcast address.
     *
     * @param host
     *            the name to resolve
     * @param type

	errReplicationUniquePriority        = Errorf("Replication configuration has duplicate priority")
	errRoleArnMissingLegacy             = Errorf("Missing required parameter `Role` in ReplicationConfiguration")
	errDestinationArnMissing            = Errorf("Missing required parameter `Destination` in Replication rule")
	errInvalidSourceSelectionCriteria   = Errorf("Invalid ReplicaModification status")

  exit 1
  ;;
esac

mkdir -p "${TARGET}"

# Download glibc's shared and development libraries based on the value of the
# `VERSION` parameter.
# Note: 'Templatizing' this and the other conditional branches would require
# defining several variables (version, os, path) making it difficult to maintain
# and extend for future modifications.
case "${VERSION}" in

        this.leaseState = 0;
        this.leaseFlags = 0;
        this.epoch = 1;
    }

    /**
     * Create a new lease V2 context request with specified parameters
     *
     * @param leaseKey the lease key
     * @param leaseState requested lease state
     * @param parentLeaseKey parent lease key (can be null for zero key)
     * @param epoch lease epoch
     */

func setTCPParametersFn(opts TCPOptions) func(network, address string, c syscall.RawConn) error {
	return func(network, address string, c syscall.RawConn) error {
		c.Control(func(fdPtr uintptr) {
			// got socket file descriptor to set parameters.
			fd := int(fdPtr)

			_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEADDR, 1)

			_ = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEPORT, 1)

			// Enable custom socket send/recv buffers.

這種情況下，你可以設定 `response_model=None` 來停用回應模型的產生：

{* ../../docs_src/response_model/tutorial003_05_py310.py hl[7] *}

這會讓 FastAPI 略過回應模型的產生，如此你就能使用任何你需要的回傳型別註解，而不會影響你的 FastAPI 應用程式。🤓

## 回應模型編碼參數 { #response-model-encoding-parameters }

你的回應模型可能有預設值，例如：

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None`（或在 Python 3.10 中的 `str | None = None`）預設為 `None`。