feat: fallback can be select by user

adapter/outboundgroup/fallback.go

@@ -3,6 +3,7 @@ package outboundgroup
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"github.com/Dreamacro/clash/adapter/outbound"
 	"github.com/Dreamacro/clash/component/dialer"
 	C "github.com/Dreamacro/clash/constant"
@@ -12,6 +13,7 @@ import (
 type Fallback struct {
 	*GroupBase
 	disableUDP bool
+	selected   string
 }
 
 func (f *Fallback) Now() string {
@@ -75,13 +77,28 @@ func (f *Fallback) Unwrap(metadata *C.Metadata) C.Proxy {
 
 func (f *Fallback) findAliveProxy(touch bool) C.Proxy {
 	proxies := f.GetProxies(touch)
-	for _, proxy := range proxies {
-		if proxy.Alive() {
+	al := proxies[0]
+	for i := len(proxies) - 1; i > -1; i-- {
+		proxy := proxies[i]
+		if proxy.Name() == f.selected && proxy.Alive() {
 			return proxy
 		}
+		if proxy.Alive() {
+			al = proxy
+		}
+	}
+	return al
+}
+
+func (f *Fallback) Set(name string) error {
+	for _, proxy := range f.GetProxies(false) {
+		if proxy.Name() == name {
+			f.selected = name
+			return nil
+		}
 	}
 
-	return proxies[0]
+	return errors.New("proxy not exist")
 }
 
 func NewFallback(option *GroupCommonOption, providers []provider.ProxyProvider) *Fallback {

adapter/outboundgroup/parser.go

@@ -76,7 +76,9 @@ func ParseProxyGroup(config map[string]any, proxyMap map[string]C.Proxy, provide
 			providersMap[groupName] = pd
 		} else {
 			if groupOption.URL == "" || groupOption.Interval == 0 {
-				return nil, errMissHealthCheck
+				//return nil, errMissHealthCheck
+				groupOption.URL = "http://www.gstatic.com/generate_204"
+				groupOption.Interval = 300
 			}
 
 			hc := provider.NewHealthCheck(ps, groupOption.URL, uint(groupOption.Interval), groupOption.Lazy)

adapter/outboundgroup/util.go

@@ -51,3 +51,7 @@ func tcpKeepAlive(c net.Conn) {
 		_ = tcp.SetKeepAlivePeriod(30 * time.Second)
 	}
 }
+
+type SelectAble interface {
+	Set(string) error
+}

hub/executor/executor.go

@@ -351,7 +351,7 @@ func patchSelectGroup(proxies map[string]C.Proxy) {
 			continue
 		}
 
-		selector, ok := outbound.ProxyAdapter.(*outboundgroup.Selector)
+		selector, ok := outbound.ProxyAdapter.(outboundgroup.SelectAble)
 		if !ok {
 			continue
 		}

hub/route/proxies.go

@@ -83,7 +83,7 @@ func updateProxy(w http.ResponseWriter, r *http.Request) {
 	}
 
 	proxy := r.Context().Value(CtxKeyProxy).(*adapter.Proxy)
-	selector, ok := proxy.ProxyAdapter.(*outboundgroup.Selector)
+	selector, ok := proxy.ProxyAdapter.(outboundgroup.SelectAble)
 	if !ok {
 		render.Status(r, http.StatusBadRequest)
 		render.JSON(w, r, newError("Must be a Selector"))