feat: add task cancellation support

- Add CancelTask function to cancel running/waiting tasks
- Add /api/cancelTask endpoint
- Add cancel button in task list for running/waiting tasks
- Check cancellation status during download and merge operations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/router/router.go

@@ -28,6 +28,7 @@ func API() *http.ServeMux {
 	router.HandleFunc("/quit", quit)
 	router.HandleFunc("/getPopularVideos", getPopularVideos)
 	router.HandleFunc("/deleteTask", deleteTask)
+	router.HandleFunc("/cancelTask", cancelTask)
 	router.HandleFunc("/getRedirectedLocation", getRedirectedLocation)
 	router.HandleFunc("/downloadVideo", downloadVideo)
 	router.HandleFunc("/getSeasonsArchivesListFirstBvid", getSeasonsArchivesListFirstBvid)

internal/router/task.go

@@ -170,3 +170,17 @@ func deleteTask(w http.ResponseWriter, r *http.Request) {
 	}
 	util.Res{Success: true, Message: "删除成功"}.Write(w)
 }
+
+func cancelTask(w http.ResponseWriter, r *http.Request) {
+	taskIDStr := r.FormValue("id")
+	taskID, err := strconv.ParseInt(taskIDStr, 10, 64)
+	if err != nil {
+		util.Res{Success: false, Message: "参数错误"}.Write(w)
+		return
+	}
+	if task.CancelTask(taskID) {
+		util.Res{Success: true, Message: "任务已取消"}.Write(w)
+	} else {
+		util.Res{Success: false, Message: "任务不存在或已完成"}.Write(w)
+	}
+}

internal/task/task.go

@@ -59,7 +59,7 @@ func (task *TaskInDB) FilePath() string {
 	)
 }
 
-// done | waiting | running | error
+// done | waiting | running | error | cancelled
 type TaskStatus string
 
 type Task struct {
@@ -67,6 +67,7 @@ type Task struct {
 	AudioProgress float64 `json:"audioProgress"`
 	VideoProgress float64 `json:"videoProgress"`
 	MergeProgress float64 `json:"mergeProgress"`
+	Cancelled     bool    `json:"cancelled"`
 }
 
 var GlobalTaskList = []*Task{}
@@ -74,6 +75,20 @@ var GlobalTaskMux = &sync.Mutex{}
 var GlobalDownloadSem = util.NewSemaphore(3)
 var GlobalMergeSem = util.NewSemaphore(3)
 
+// CancelTask 取消指定任务
+func CancelTask(taskID int64) bool {
+	GlobalTaskMux.Lock()
+	defer GlobalTaskMux.Unlock()
+	for _, task := range GlobalTaskList {
+		if task.ID == taskID && (task.Status == "waiting" || task.Status == "running") {
+			task.Cancelled = true
+			task.Status = "error"
+			return true
+		}
+	}
+	return false
+}
+
 func (task *Task) Create(db *sql.DB) error {
 	util.SqliteLock.Lock()
 	result, err := db.Exec(`INSERT INTO "task" ("bvid", "cid", "format", "title", "owner", "cover", "status", "folder", "duration", "download_type")
@@ -109,6 +124,13 @@ func (task *Task) Start() {
 	GlobalTaskMux.Unlock()
 	db := util.MustGetDB()
 	defer db.Close()
+
+	// 检查是否已取消
+	if task.Cancelled {
+		task.UpdateStatus(db, "error", fmt.Errorf("任务已取消"))
+		return
+	}
+
 	sessdata, err := bilibili.GetSessdata(db)
 	if err != nil {
 		task.UpdateStatus(db, "error", fmt.Errorf("bilibili.GetSessdata: %v", err))
@@ -124,14 +146,26 @@ func (task *Task) Start() {
 	client := &bilibili.BiliClient{SESSDATA: sessdata}
 
 	GlobalDownloadSem.Acquire()
+
+	// 再次检查是否已取消
+	if task.Cancelled {
+		GlobalDownloadSem.Release()
+		task.UpdateStatus(db, "error", fmt.Errorf("任务已取消"))
+		return
+	}
+
 	task.UpdateStatus(db, "running")
 
 	if task.DownloadType == "audio" {
 		// 仅音频模式：只下载音频，重命名音频文件为输出文件
 		err = DownloadMedia(client, task.Audio, task, "audio")
-		if err != nil {
+		if err != nil || task.Cancelled {
 			GlobalDownloadSem.Release()
-			task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			if task.Cancelled {
+				task.UpdateStatus(db, "error", fmt.Errorf("任务已取消"))
+			} else {
+				task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			}
 			return
 		}
 		GlobalDownloadSem.Release()
@@ -151,9 +185,13 @@ func (task *Task) Start() {
 	} else if task.DownloadType == "video" {
 		// 仅视频模式：只下载视频，重命名视频文件为输出文件
 		err = DownloadMedia(client, task.Video, task, "video")
-		if err != nil {
+		if err != nil || task.Cancelled {
 			GlobalDownloadSem.Release()
-			task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			if task.Cancelled {
+				task.UpdateStatus(db, "error", fmt.Errorf("任务已取消"))
+			} else {
+				task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			}
 			return
 		}
 		GlobalDownloadSem.Release()
@@ -173,19 +211,32 @@ func (task *Task) Start() {
 	} else {
 		// 合并模式：下载音频和视频，然后合并
 		err = DownloadMedia(client, task.Audio, task, "audio")
-		if err != nil {
+		if err != nil || task.Cancelled {
 			GlobalDownloadSem.Release()
-			task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			if task.Cancelled {
+				task.UpdateStatus(db, "error", fmt.Errorf("任务已取消"))
+			} else {
+				task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			}
 			return
 		}
 		err = DownloadMedia(client, task.Video, task, "video")
-		if err != nil {
+		if err != nil || task.Cancelled {
 			GlobalDownloadSem.Release()
-			task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			if task.Cancelled {
+				task.UpdateStatus(db, "error", fmt.Errorf("任务已取消"))
+			} else {
+				task.UpdateStatus(db, "error", fmt.Errorf("DownloadMedia: %v", err))
+			}
 			return
 		}
 		GlobalDownloadSem.Release()
 
+		if task.Cancelled {
+			task.UpdateStatus(db, "error", fmt.Errorf("任务已取消"))
+			return
+		}
+
 		outputPath := task.TaskInDB.FilePath()
 		videoPath := filepath.Join(task.Folder, strconv.FormatInt(task.ID, 10)+".video")
 		audioPath := filepath.Join(task.Folder, strconv.FormatInt(task.ID, 10)+".audio")