feat: improve http download strategy to prevent speed drops near completion (#969)

pkg/download/downloader.go

@@ -148,6 +148,7 @@ func (d *Downloader) Setup() error {
 				tasks = append(tasks[:i], tasks[i+1:]...)
 				continue
 			}
+			d.assignFetcherManager(task)
 			initTask(task)
 			if task.Status != base.DownloadStatusDone && task.Status != base.DownloadStatusError {
 				task.Status = base.DownloadStatusPause
@@ -892,18 +893,7 @@ func (d *Downloader) restoreTask(task *Task) error {
 }
 
 func (d *Downloader) restoreFetcher(task *Task) error {
-	var fm fetcher.FetcherManager
-	for _, f := range d.cfg.FetchManagers {
-		if f.Name() == task.Protocol {
-			fm = f
-			break
-		}
-	}
-	if fm == nil {
-		return ErrUnSupportedProtocol
-	}
-	task.fetcherManager = fm
-	v, f := fm.Restore()
+	v, f := task.fetcherManager.Restore()
 	if v != nil {
 		err := d.storage.Pop(bucketSave, task.ID, v)
 		if err != nil {
@@ -1145,6 +1135,15 @@ func logPanic(logDir string) {
 	debug.SetCrashOutput(f, debug.CrashOptions{})
 }
 
+func (d *Downloader) assignFetcherManager(task *Task) error {
+	fm, err := d.parseFm(task.Meta.Req.URL)
+	if err != nil {
+		return err
+	}
+	task.fetcherManager = fm
+	return nil
+}
+
 func (d *Downloader) buildFetcher(url string) (fetcher.Fetcher, error) {
 	fm, err := d.parseFm(url)
 	if err != nil {

pkg/protocol/http/model.go

@@ -14,6 +14,12 @@ type OptsExtra struct {
 
 // Stats for download
 type Stats struct {
-	// http stats
-	// health indicators of http
+	Connections []*StatsConnection `json:"connections"`
+}
+
+type StatsConnection struct {
+	Downloaded int64 `json:"downloaded"`
+	Completed  bool  `json:"completed"`
+	Failed     bool  `json:"failed"`
+	RetryTimes int   `json:"retryTimes"`
 }