Feature: add experimental provider

adapters/outboundgroup/fallback.go

@@ -0,0 +1,84 @@
+package outboundgroup
+
+import (
+	"context"
+	"encoding/json"
+	"net"
+
+	"github.com/Dreamacro/clash/adapters/outbound"
+	"github.com/Dreamacro/clash/adapters/provider"
+	C "github.com/Dreamacro/clash/constant"
+)
+
+type Fallback struct {
+	*outbound.Base
+	providers []provider.ProxyProvider
+}
+
+func (f *Fallback) Now() string {
+	proxy := f.findAliveProxy()
+	return proxy.Name()
+}
+
+func (f *Fallback) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
+	proxy := f.findAliveProxy()
+	c, err := proxy.DialContext(ctx, metadata)
+	if err == nil {
+		c.AppendToChains(f)
+	}
+	return c, err
+}
+
+func (f *Fallback) DialUDP(metadata *C.Metadata) (C.PacketConn, net.Addr, error) {
+	proxy := f.findAliveProxy()
+	pc, addr, err := proxy.DialUDP(metadata)
+	if err == nil {
+		pc.AppendToChains(f)
+	}
+	return pc, addr, err
+}
+
+func (f *Fallback) SupportUDP() bool {
+	proxy := f.findAliveProxy()
+	return proxy.SupportUDP()
+}
+
+func (f *Fallback) MarshalJSON() ([]byte, error) {
+	var all []string
+	for _, proxy := range f.proxies() {
+		all = append(all, proxy.Name())
+	}
+	return json.Marshal(map[string]interface{}{
+		"type": f.Type().String(),
+		"now":  f.Now(),
+		"all":  all,
+	})
+}
+
+func (f *Fallback) proxies() []C.Proxy {
+	proxies := []C.Proxy{}
+	for _, provider := range f.providers {
+		proxies = append(proxies, provider.Proxies()...)
+	}
+	return proxies
+}
+
+func (f *Fallback) findAliveProxy() C.Proxy {
+	for _, provider := range f.providers {
+		proxies := provider.Proxies()
+		for _, proxy := range proxies {
+			if proxy.Alive() {
+				return proxy
+			}
+		}
+	}
+
+	return f.providers[0].Proxies()[0]
+}
+
+func NewFallback(name string, providers []provider.ProxyProvider) *Fallback {
+	return &Fallback{
+		Base:      outbound.NewBase(name, C.Fallback, false),
+		providers: providers,
+	}
+}