使用路径装饰器依赖项还可以避免开发新人误会代码中包含无用的未使用参数。

///

/// info | "说明"

本例中，使用的是自定义响应头 `X-Key` 和 `X-Token`。

但实际开发中，尤其是在实现安全措施时，最好使用 FastAPI 内置的[安全工具](../security/index.md){.internal-link target=_blank}（详见下一章）。

///

## 依赖项错误和返回值

路径装饰器依赖项也可以使用普通的依赖项*函数*。

### 依赖项的需求项

路径装饰器依赖项可以声明请求的需求项（比如响应头）或其他子依赖项：

```Python hl_lines="6  11"

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.proxy

import java.io.IOException
import java.net.Proxy
import java.net.ProxySelector
import java.net.SocketAddress
import java.net.URI

/**
 * A proxy selector that always returns the [Proxy.NO_PROXY].

    cm: ContextManager[_T],
) -> AsyncGenerator[_T, None]:
    # blocking __exit__ from running waiting on a free thread
    # can create race conditions/deadlocks if the context manager itself
    # has its own internal pool (e.g. a database connection pool)
    # to avoid this we let __exit__ run without a capacity limit
    # since we're creating a new limiter for each call, any non-zero limit
    # works (1 is arbitrary)

如果可以，请尽量使用 `Annotated` 版本。

///

```Python hl_lines="16-20  29"
{!> ../../docs_src/dependencies/tutorial008b.py!}
```

////

你还可以创建一个 [自定义异常处理器](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank} 用于捕获异常（同时也可以抛出另一个 `HTTPException`）。

## 包含 `yield` 和 `except` 的依赖项

如果你在包含 `yield` 的依赖项中使用 `except` 捕获了一个异常，然后你没有重新抛出该异常（或抛出一个新异常），与在普通的Python代码中相同，FastAPI不会注意到发生了异常。

//// tab | Python 3.9+

Wie Sie im vorherigen Kapitel über [Deployment-Konzepte](concepts.md){.internal-link target=_blank} gesehen haben, gibt es mehrere Strategien, die Sie anwenden können.

import com.google.common.annotations.GwtCompatible;

/**
 * The subset of the {@link java.util.regex.Pattern} API which is used by this package, and also
 * shared with the {@code re2j} library. For internal use only. Please refer to the {@code Pattern}
 * javadoc for details.
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
abstract class CommonPattern {
  public abstract CommonMatcher matcher(CharSequence t);

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package callhome

import "github.com/minio/minio/internal/config"

var (
	defaultHelpPostfix = func(key string) string {
		return config.DefaultHelpPostfix(DefaultKVS, key)
	}

	// HelpCallhome - provides help for callhome config
	HelpCallhome = config.HelpKVS{

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package gradlebuild.docs

import org.gradle.util.internal.TextUtil
import spock.lang.Specification

class UserGuideTransformTaskTest extends Specification {

    def replacesTabsWith4Spaces() {
        given:
        String content = "test\ttest\ttest"
        when:

 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.internal.smb2.create;


import jcifs.Decodable;


/**
 * @author mbechler
 *
 */
public interface CreateContextResponse extends Decodable {

    /**
     * @return context name
     */

 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.internal.smb2.nego;


import jcifs.Encodable;


/**
 * @author mbechler
 *
 */
public interface NegotiateContextRequest extends Encodable {

    /**
     * 
     * @return context type
     */