host, err := xnet.ParseHost(serverAddr)
	if err != nil {
		return config.ErrInvalidAddressFlag(err)
	}

	// 0.0.0.0 is a wildcard address and refers to local network
	// addresses. I.e, 0.0.0.0:9000 like ":9000" refers to port
	// 9000 on localhost.
	if host.Name != "" && host.Name != net.IPv4zero.String() && host.Name != net.IPv6zero.String() {

  // be one of the following values:
  // * Exact: Matches the URL path exactly.
  // * Prefix: Matches based on a URL path prefix split by '/'. Matching is
  //   done on a path element by element basis. A path element refers is the
  //   list of labels in the path split by the '/' separator. A request is a
  //   match for path p if every p is an element-wise prefix of p of the

=== "Python 3.8+"

    ```Python hl_lines="21"
    {!> ../../../docs_src/path_operation_configuration/tutorial005.py!}
    ```

!!! info
    Notice that `response_description` refers specifically to the response, the `description` refers to the *path operation* in general.

!!! check
    OpenAPI specifies that each *path operation* requires a response description.

高度なシナリオでは、「キャッシュされた」値を使うのではなく、同じリクエストの各ステップ（おそらく複数回）で依存関係を呼び出す必要があることがわかっている場合、`Depens`を使用する際に、`use_cache=False`というパラメータを設定することができます。

```Python hl_lines="1"
async def needy_dependency(fresh_value: str = Depends(get_value, use_cache=False)):
    return {"fresh_value": fresh_value}
```

## まとめ

ここで使われている派手な言葉は別にして、**依存性注入** システムは非常にシンプルです。

*path operation関数*と同じように見えるただの関数です。

しかし、それでも非常に強力で、任意の深くネストされた依存関係「グラフ」（ツリー）を宣言することができます。

        .minFresh(3.seconds)
        .onlyIfCached()
        .noTransform()
        .immutable()
        .build()
    assertThat(cacheControl.toString()).isEqualTo(
      "no-cache, no-store, max-age=1, max-stale=2, min-fresh=3, only-if-cached, no-transform, immutable",
    )
    assertThat(cacheControl.noCache).isTrue()
    assertThat(cacheControl.noStore).isTrue()
    assertThat(cacheControl.maxAgeSeconds).isEqualTo(1)

        // Here, we need to determine which policy to use. Release updateInterval will be used when
        // the metadata refers to a release artifact or meta-version, and snapshot updateInterval will be used when
        // it refers to a snapshot artifact or meta-version.
        // NOTE: Release metadata includes version information about artifacts that have been released, to allow

        .onlyIfCached()
        .noTransform()
        .immutable()
        .build()
    assertThat(cacheControl.toString()).isEqualTo(
      "no-cache, no-store, max-age=1, max-stale=2, min-fresh=3, only-if-cached, " +
        "no-transform, immutable",
    )
    assertThat(cacheControl.noCache).isTrue()
    assertThat(cacheControl.noStore).isTrue()
    assertThat(cacheControl.maxAgeSeconds).isEqualTo(1)

        if (mustRevalidate) append("must-revalidate, ")
        if (maxStaleSeconds != -1) append("max-stale=").append(maxStaleSeconds).append(", ")
        if (minFreshSeconds != -1) append("min-fresh=").append(minFreshSeconds).append(", ")
        if (onlyIfCached) append("only-if-cached, ")
        if (noTransform) append("no-transform, ")
        if (immutable) append("immutable, ")
        if (isEmpty()) return ""

8. Notice that this *path operation function* uses regular `def` instead of `async def`.

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

var errSkipFile = errors.New("skip this file")

var errIgnoreFileContrib = errors.New("ignore this file's contribution toward data-usage")

// errXLBackend XL drive mode requires fresh deployment.
var errXLBackend = errors.New("XL backend requires fresh drive")

// StorageErr represents error generated by xlStorage call.
type StorageErr string

func (h StorageErr) Error() string {
	return string(h)
}