```Python hl_lines="4"
{!../../docs_src/dependencies/tutorial007.py!}
```

`yield` 语句后面的代码会在创建响应后，发送响应前执行：

```Python hl_lines="5-6"
{!../../docs_src/dependencies/tutorial007.py!}
```

/// tip | 提示

你可以使用 `async` 或普通函数。

**FastAPI** 会像处理普通依赖一样，对每个依赖做正确的处理。

///

## 包含 `yield` 和 `try` 的依赖项

如果在包含 `yield` 的依赖中使用 `try` 代码块，你会捕获到使用依赖时抛出的任何异常。

例如，如果某段代码在另一个依赖中或在 *路由函数* 中使数据库事务"回滚"或产生任何其他错误，你将会在依赖中捕获到异常。

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"sync"
	"time"

	jwtgo "github.com/golang-jwt/jwt/v4"
	"github.com/minio/minio/internal/arn"
	"github.com/minio/minio/internal/auth"
	xnet "github.com/minio/pkg/v3/net"
	"github.com/minio/pkg/v3/policy"
)

type publicKeys struct {
	*sync.RWMutex

	// map of kid to public key
	pkMap map[string]interface{}
}

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"bytes"
	"context"
	"encoding/hex"
	"fmt"
	"os"
	"reflect"
	"sync"

	"github.com/cespare/xxhash/v2"
	"github.com/klauspost/reedsolomon"
	"github.com/minio/minio/internal/logger"
)

// Erasure - erasure encoding details.
type Erasure struct {

	WithPayload bool

	// Override the default capacities (1)
	OutCapacity int

	// Set to 0 if no input is expected.
	// Will be 0 if newReq is nil.
	InCapacity int

	reqPool        sync.Pool
	respPool       sync.Pool
	id             HandlerID
	newPayload     func() Payload
	nilReq         Req
	nilResp        Resp
	sharedResponse bool
}

package tests_test

import (
	"context"
	"encoding/json"
	"regexp"
	"sort"
	"strconv"
	"sync"
	"testing"
	"time"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
	. "gorm.io/gorm/utils/tests"
)

func TestPreloadWithAssociations(t *testing.T) {
	user := *GetUser("preload_with_associations", Config{
		Account:   true,
		Pets:      2,
		Toys:      3,
		Company:   true,
		Manager:   true,
		Team:      4,

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package openid

import (
	"crypto/sha1"
	"encoding/base64"
	"errors"
	"io"
	"net/http"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/minio/madmin-go/v3"
	"github.com/minio/minio-go/v7/pkg/set"
	"github.com/minio/minio/internal/arn"
	"github.com/minio/minio/internal/auth"
	"github.com/minio/minio/internal/config"

// See the License for the specific language governing permissions and
// limitations under the License.

package nodeagent

import (
	"context"
	"errors"
	"fmt"
	"net/netip"
	"os"
	"path/filepath"
	"sync/atomic"

	"golang.org/x/sys/unix"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"

	pconstants "istio.io/istio/cni/pkg/constants"
	"istio.io/istio/cni/pkg/ipset"

```Python hl_lines="2  7  9"
{!../../docs_src/custom_response/tutorial006c.py!}
```

### `StreamingResponse`

Takes an async generator or a normal generator/iterator and streams the response body.

```Python hl_lines="2  14"
{!../../docs_src/custom_response/tutorial007.py!}
```

#### Using `StreamingResponse` with file-like objects

				remaining--
			}
		}
	}
	return entries, nil
}

func globalSync() {
	// no-op not sure about plan9/solaris support for syscall support
	defer globalOSMetrics.time(osMetricSync)()
	syscall.Sync()

golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=