fix: 还未生成截图, 访问应答404问题; 截图缩放到960*540大小;

api/api.go

@@ -259,6 +259,22 @@ func (api *ApiServer) registerStatisticsHandler(actionName, path string, handler
 	api.actionNames[path] = actionName
 }
 
+type SnapshotFilter struct {
+}
+
+func (f *SnapshotFilter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if "" != r.URL.Query().Get("preview_snapshot") {
+		t := r.URL.Query().Get("t")
+		ok := DefaultSnapshotManager.Get(t, 2*time.Second)
+		if !ok {
+			w.WriteHeader(http.StatusNotFound)
+			return
+		}
+	}
+
+	http.FileServer(http.Dir("./snapshot")).ServeHTTP(w, r)
+}
+
 func StartApiServer(addr string) {
 	apiServer.router.HandleFunc("/api/v1/hook/on_play", common.WithJsonParams(apiServer.OnPlay, &PlayDoneParams{}))
 	apiServer.router.HandleFunc("/api/v1/hook/on_play_done", common.WithJsonParams(apiServer.OnPlayDone, &PlayDoneParams{}))
@@ -268,7 +284,7 @@ func StartApiServer(addr string) {
 	apiServer.router.HandleFunc("/api/v1/hook/on_receive_timeout", common.WithJsonParams(apiServer.OnReceiveTimeout, &StreamParams{}))
 	apiServer.router.HandleFunc("/api/v1/hook/on_record", common.WithJsonParams(apiServer.OnRecord, &RecordParams{}))
 	apiServer.router.HandleFunc("/api/v1/hook/on_started", apiServer.OnStarted)
-	apiServer.router.HandleFunc("/api/v1/hook/on_snapshot", common.WithJsonParams(apiServer.OnSnapshot, &SnapshotParams{}))
+	apiServer.router.HandleFunc("/api/v1/hook/on_snapshot", apiServer.OnSnapshot)
 
 	apiServer.registerStatisticsHandler("开始预览", "/api/v1/stream/start", withVerify(common.WithFormDataParams(apiServer.OnStreamStart, InviteParams{})))           // 实时预览
 	apiServer.registerStatisticsHandler("停止预览", "/api/v1/stream/stop", withVerify(common.WithFormDataParams(apiServer.OnCloseLiveStream, InviteParams{})))        // 关闭实时预览
@@ -411,7 +427,8 @@ func StartApiServer(addr string) {
 	})
 
 	// 映射snapshot目录
-	apiServer.router.PathPrefix("/snapshot/").Handler(http.StripPrefix("/snapshot/", http.FileServer(http.Dir("./snapshot"))))
+	filter := SnapshotFilter{}
+	apiServer.router.PathPrefix("/snapshot/").Handler(http.StripPrefix("/snapshot/", &filter))
 
 	// 前端路由
 	htmlRoot := "./html/"

api/api_hook.go

@@ -8,6 +8,7 @@ import (
 	"gb-cms/stack"
 	"github.com/csnewman/ffmpeg-go"
 	"github.com/lkmio/avformat/utils"
+	"io"
 	"net/http"
 	"os"
 	"path"
@@ -234,11 +235,28 @@ func (api *ApiServer) OnStarted(_ http.ResponseWriter, _ *http.Request) {
 	}
 }
 
-func (api *ApiServer) OnSnapshot(v *SnapshotParams, writer http.ResponseWriter, request *http.Request) {
+func (api *ApiServer) OnSnapshot(w http.ResponseWriter, r *http.Request) {
 	if VideoKeyFrame2JPG == nil {
 		return
 	}
 
+	r.Body = http.MaxBytesReader(w, r.Body, 1024*1024*2)
+	data, err := io.ReadAll(r.Body)
+	if err != nil {
+		if err.Error() == "http: request body too large" {
+			http.Error(w, "file too large", http.StatusRequestEntityTooLarge)
+		} else {
+			http.Error(w, "read body failed", http.StatusInternalServerError)
+		}
+		return
+	}
+
+	v := &SnapshotParams{}
+	v.Stream = common.StreamID(r.Header.Get("stream"))
+	v.Session = r.Header.Get("session")
+	v.Codec = r.Header.Get("codec")
+	v.KeyFrameData = data
+
 	var codecId ffmpeg.AVCodecID
 	switch strings.ToLower(v.Codec) {
 	case "h264":
@@ -250,8 +268,8 @@ func (api *ApiServer) OnSnapshot(v *SnapshotParams, writer http.ResponseWriter,
 		return
 	}
 
-	jpgPath := GetSnapshotPath(v.Stream, v.Session)
-	err := os.MkdirAll(path.Dir(jpgPath), 0755)
+	jpgPath := GetSnapshotPath(v.Stream)
+	err = os.MkdirAll(path.Dir(jpgPath), 0755)
 	if err != nil {
 		log.Sugar.Errorf("创建目录失败 err: %s", err.Error())
 		return
@@ -261,16 +279,18 @@ func (api *ApiServer) OnSnapshot(v *SnapshotParams, writer http.ResponseWriter,
 	err = VideoKeyFrame2JPG(codecId, v.KeyFrameData, jpgPath)
 	if err != nil {
 		log.Sugar.Errorf("转换为JPEG失败 err: %s", err.Error())
-	} else if err = dao.Channel.SetSnapshotPath(v.Stream.DeviceID(), v.Stream.ChannelID(), jpgPath); err != nil {
+	} else if err = dao.Channel.SetSnapshotPath(v.Stream.DeviceID(), v.Stream.ChannelID(), jpgPath+"?t="+v.Session); err != nil {
 		// 数据库更新通道的最新截图
 		log.Sugar.Errorf("更新通道最新截图失败 err: %s", err.Error())
+	} else {
+		DefaultSnapshotManager.Put(v.Session, true)
 	}
 }
 
-func GetSnapshotPath(streamID common.StreamID, sessionID string) string {
+func GetSnapshotPath(streamID common.StreamID) string {
 	if VideoKeyFrame2JPG == nil {
 		return ""
 	}
 
-	return path.Join("./snapshot/", string(streamID), sessionID+".jpg")
+	return path.Join("./snapshot/", string(streamID)+".jpg")
 }

api/api_stream.go

@@ -116,7 +116,7 @@ func (api *ApiServer) DoStartStream(v *InviteParams, w http.ResponseWriter, r *h
 		RecordStartAt:         "",
 		RelaySize:             0,
 		SMSID:                 "",
-		SnapURL:               GetSnapshotPath(stream.StreamID, stream.SessionID),
+		SnapURL:               GetSnapshotPath(stream.StreamID) + "?preview_snapshot=1&t=" + stream.SessionID,
 		SourceAudioCodecName:  "",
 		SourceAudioSampleRate: 0,
 		SourceVideoCodecName:  "",

api/snapshot.go

@@ -3,8 +3,10 @@
 package api
 
 import (
+	"bytes"
 	"fmt"
 	"github.com/csnewman/ffmpeg-go"
+	"github.com/disintegration/imaging"
 	"os"
 	"unsafe"
 )
@@ -111,9 +113,41 @@ func saveFrameAsJPEG(frame *ffmpeg.AVFrame, filename string) error {
 		return fmt.Errorf("接收包失败 %v", err)
 	}
 
-	// 写入文件
-	if _, err := file.Write(unsafe.Slice((*byte)(pkt.Data()), pkt.Size())); err != nil {
-		return fmt.Errorf("写入文件失败 %v", err)
+	// 获取编码后的 JPEG 原始字节数据
+	jpegBytes := unsafe.Slice((*byte)(pkt.Data()), pkt.Size())
+
+	// 判断是否需要缩放
+	targetW, targetH := 960, 540
+	if (frame.Width() > frame.Height()) && frame.Width() > targetW || frame.Height() > targetH {
+		// [路径 A: 需要缩放]
+
+		// 1. 将 JPEG 字节流解码为 Go Image 对象
+		img, err := imaging.Decode(bytes.NewReader(jpegBytes))
+		if err != nil {
+			return fmt.Errorf("Go解码图片失败: %v", err)
+		}
+
+		// 2. 使用 imaging 库进行缩放 (Fit 会保持比例，适应 960x540 的框)
+		// 使用 Lanczos 算法保证缩放后的清晰度
+		dstImg := imaging.Fit(img, targetW, targetH, imaging.Lanczos)
+
+		// 3. 保存缩放后的图片到文件
+		if err := imaging.Save(dstImg, filename, imaging.JPEGQuality(80)); err != nil {
+			return fmt.Errorf("保存缩放图片失败: %v", err)
+		}
+
+	} else {
+		// [路径 B: 不需要缩放]
+		// 直接将 FFmpeg 编码好的字节写入文件，效率最高
+		file, err := os.Create(filename)
+		if err != nil {
+			return fmt.Errorf("创建文件失败 %v", err)
+		}
+		defer file.Close()
+
+		if _, err := file.Write(jpegBytes); err != nil {
+			return fmt.Errorf("写入文件失败 %v", err)
+		}
 	}
 
 	return nil

api/snapshot_async.go

@@ -0,0 +1,63 @@
+package api
+
+import (
+	"container/list"
+	"context"
+	"sync"
+	"time"
+)
+
+const (
+	SnapshotQueueMaxSize = 128
+)
+
+var (
+	DefaultSnapshotManager = &SnapshotManager{
+		snapshots: make(map[string][]func(), SnapshotQueueMaxSize*1.5),
+		keys:      list.New(),
+	}
+)
+
+type SnapshotManager struct {
+	lock      sync.RWMutex
+	snapshots map[string][]func()
+	keys      *list.List
+}
+
+func (s *SnapshotManager) Get(id string, timeout time.Duration) bool {
+	s.lock.Lock()
+	if _, ok := s.snapshots[id]; ok {
+		s.lock.Unlock()
+		return true
+	}
+
+	background, cancel := context.WithCancel(context.Background())
+	s.snapshots[id] = append(s.snapshots[id], cancel)
+	// 超时未获取到截图, 则认为不存在
+	after := time.After(timeout)
+
+	s.lock.Unlock()
+	select {
+	case <-after:
+		return false
+	case <-background.Done():
+		return true
+	}
+}
+
+func (s *SnapshotManager) Put(id string, ok bool) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	// 通知获取截图的goroutine, 截图已准备好
+	for _, cancel := range s.snapshots[id] {
+		cancel()
+	}
+
+	// 超出最大队列长度, 则删除最早的截图
+	for s.keys.Len() > SnapshotQueueMaxSize {
+		oldElement := s.keys.Front()
+		s.keys.Remove(oldElement)
+		delete(s.snapshots, oldElement.Value.(string))
+	}
+}

go.mod

@@ -43,6 +43,7 @@ require (
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	go.uber.org/multierr v1.10.0 // indirect
 	golang.org/x/crypto v0.24.0 // indirect
+	golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8 // indirect
 	golang.org/x/sys v0.21.0 // indirect
 	golang.org/x/term v0.21.0 // indirect
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect
@@ -54,6 +55,7 @@ require (
 
 require (
 	github.com/csnewman/ffmpeg-go v0.6.0
+	github.com/disintegration/imaging v1.6.2
 	github.com/glebarez/sqlite v1.11.0
 	github.com/go-co-op/gocron/v2 v2.16.6
 	github.com/gorilla/mux v1.8.1