feat: proxy provider 支持V2ray格式订阅链接

adapter/provider/fetcher.go

@@ -16,42 +16,35 @@ var (
 	dirMode  os.FileMode = 0o755
 )
 
-type parser = func([]byte) (any, error)
+type parser[V any] func([]byte) (V, error)
 
-type fetcher struct {
+type fetcher[V any] struct {
 	name      string
 	vehicle   types.Vehicle
 	updatedAt *time.Time
 	ticker    *time.Ticker
 	done      chan struct{}
 	hash      [16]byte
-	parser    parser
+	parser    parser[V]
 	interval  time.Duration
-	onUpdate  func(any)
+	onUpdate  func(V)
 }
 
-func (f *fetcher) Name() string {
+func (f *fetcher[V]) Name() string {
 	return f.name
 }
 
-func (f *fetcher) VehicleType() types.VehicleType {
+func (f *fetcher[V]) VehicleType() types.VehicleType {
 	return f.vehicle.Type()
 }
 
-func (f *fetcher) Initial() (any, error) {
+func (f *fetcher[V]) Initial() (V, error) {
 	var (
 		buf     []byte
 		err     error
 		isLocal bool
 	)
 
-	defer func() {
-		// pull proxies automatically
-		if f.ticker != nil {
-			go f.pullLoop()
-		}
-	}()
-
 	if stat, fErr := os.Stat(f.vehicle.Path()); fErr == nil {
 		buf, err = os.ReadFile(f.vehicle.Path())
 		modTime := stat.ModTime()
@@ -60,7 +53,7 @@ func (f *fetcher) Initial() (any, error) {
 		if f.interval != 0 && modTime.Add(f.interval).Before(time.Now()) {
 			defer func() {
 				log.Infoln("[Provider] %s's proxies not updated for a long time, force refresh", f.Name())
-				go f.update()
+				go f.Update()
 			}()
 		}
 	} else {
@@ -68,24 +61,24 @@ func (f *fetcher) Initial() (any, error) {
 	}
 
 	if err != nil {
-		return nil, err
+		return getZero[V](), err
 	}
 
 	proxies, err := f.parser(buf)
 	if err != nil {
 		if !isLocal {
-			return nil, err
+			return getZero[V](), err
 		}
 
 		// parse local file error, fallback to remote
 		buf, err = f.vehicle.Read()
 		if err != nil {
-			return nil, err
+			return getZero[V](), err
 		}
 
 		proxies, err = f.parser(buf)
 		if err != nil {
-			return nil, err
+			return getZero[V](), err
 		}
 
 		isLocal = false
@@ -93,19 +86,24 @@ func (f *fetcher) Initial() (any, error) {
 
 	if f.vehicle.Type() != types.File && !isLocal {
 		if err := safeWrite(f.vehicle.Path(), buf); err != nil {
-			return nil, err
+			return getZero[V](), err
 		}
 	}
 
 	f.hash = md5.Sum(buf)
 
+	// pull proxies automatically
+	if f.ticker != nil {
+		go f.pullLoop()
+	}
+
 	return proxies, nil
 }
 
-func (f *fetcher) Update() (any, bool, error) {
+func (f *fetcher[V]) Update() (V, bool, error) {
 	buf, err := f.vehicle.Read()
 	if err != nil {
-		return nil, false, err
+		return getZero[V](), false, err
 	}
 
 	now := time.Now()
@@ -113,17 +111,17 @@ func (f *fetcher) Update() (any, bool, error) {
 	if bytes.Equal(f.hash[:], hash[:]) {
 		f.updatedAt = &now
 		os.Chtimes(f.vehicle.Path(), now, now)
-		return nil, true, nil
+		return getZero[V](), true, nil
 	}
 
 	proxies, err := f.parser(buf)
 	if err != nil {
-		return nil, false, err
+		return getZero[V](), false, err
 	}
 
 	if f.vehicle.Type() != types.File {
 		if err := safeWrite(f.vehicle.Path(), buf); err != nil {
-			return nil, false, err
+			return getZero[V](), false, err
 		}
 	}
 
@@ -133,22 +131,32 @@ func (f *fetcher) Update() (any, bool, error) {
 	return proxies, false, nil
 }
 
-func (f *fetcher) Destroy() error {
+func (f *fetcher[V]) Destroy() error {
 	if f.ticker != nil {
 		f.done <- struct{}{}
 	}
 	return nil
 }
 
-func (f *fetcher) pullLoop() {
+func (f *fetcher[V]) pullLoop() {
 	for {
 		select {
 		case <-f.ticker.C:
-			same, err := f.update()
-			if same || err != nil {
+			elm, same, err := f.Update()
+			if err != nil {
+				log.Warnln("[Provider] %s pull error: %s", f.Name(), err.Error())
 				continue
 			}
 
+			if same {
+				log.Debugln("[Provider] %s's proxies doesn't change", f.Name())
+				continue
+			}
+
+			log.Infoln("[Provider] %s's proxies update", f.Name())
+			if f.onUpdate != nil {
+				f.onUpdate(elm)
+			}
 		case <-f.done:
 			f.ticker.Stop()
 			return
@@ -156,26 +164,6 @@ func (f *fetcher) pullLoop() {
 	}
 }
 
-func (f *fetcher) update() (same bool, err error) {
-	elm, same, err := f.Update()
-	if err != nil {
-		log.Warnln("[Provider] %s pull error: %s", f.Name(), err.Error())
-		return
-	}
-
-	if same {
-		log.Debugln("[Provider] %s's proxies doesn't change", f.Name())
-		return
-	}
-
-	if f.onUpdate != nil {
-		f.onUpdate(elm)
-	}
-
-	log.Infoln("[Provider] %s's proxies update", f.Name())
-	return
-}
-
 func safeWrite(path string, buf []byte) error {
 	dir := filepath.Dir(path)
 
@@ -188,19 +176,23 @@ func safeWrite(path string, buf []byte) error {
 	return os.WriteFile(path, buf, fileMode)
 }
 
-func newFetcher(name string, interval time.Duration, vehicle types.Vehicle, parser parser, onUpdate func(any)) *fetcher {
+func newFetcher[V any](name string, interval time.Duration, vehicle types.Vehicle, parser parser[V], onUpdate func(V)) *fetcher[V] {
 	var ticker *time.Ticker
 	if interval != 0 {
 		ticker = time.NewTicker(interval)
 	}
 
-	return &fetcher{
+	return &fetcher[V]{
 		name:     name,
 		ticker:   ticker,
 		vehicle:  vehicle,
 		parser:   parser,
 		done:     make(chan struct{}, 1),
 		onUpdate: onUpdate,
-		interval: interval,
 	}
 }
+
+func getZero[V any]() V {
+	var result V
+	return result
+}