Feature: add `filter` option to proxy group (#2518)

adapter/outboundgroup/parser.go

@@ -3,6 +3,7 @@ package outboundgroup
 import (
 	"errors"
 	"fmt"
+	"regexp"
 
 	"github.com/Dreamacro/clash/adapter/outbound"
 	"github.com/Dreamacro/clash/adapter/provider"
@@ -29,6 +30,7 @@ type GroupCommonOption struct {
 	Interval   int      `group:"interval,omitempty"`
 	Lazy       bool     `group:"lazy,omitempty"`
 	DisableUDP bool     `group:"disable-udp,omitempty"`
+	Filter     string   `group:"filter,omitempty"`
 }
 
 func ParseProxyGroup(config map[string]any, proxyMap map[string]C.Proxy, providersMap map[string]types.ProxyProvider) (C.ProxyAdapter, error) {
@@ -45,14 +47,25 @@ func ParseProxyGroup(config map[string]any, proxyMap map[string]C.Proxy, provide
 		return nil, errFormat
 	}
 
-	groupName := groupOption.Name
+	var (
+		groupName = groupOption.Name
+		filterReg *regexp.Regexp
+	)
 
-	providers := []types.ProxyProvider{}
+	if groupOption.Filter != "" {
+		f, err := regexp.Compile(groupOption.Filter)
+		if err != nil {
+			return nil, fmt.Errorf("%s: invalid filter regex: %w", groupName, err)
+		}
+		filterReg = f
+	}
 
 	if len(groupOption.Proxies) == 0 && len(groupOption.Use) == 0 {
 		return nil, fmt.Errorf("%s: %w", groupName, errMissProxy)
 	}
 
+	providers := []types.ProxyProvider{}
+
 	if len(groupOption.Proxies) != 0 {
 		ps, err := getProxies(proxyMap, groupOption.Proxies)
 		if err != nil {
@@ -94,7 +107,12 @@ func ParseProxyGroup(config map[string]any, proxyMap map[string]C.Proxy, provide
 		if err != nil {
 			return nil, fmt.Errorf("%s: %w", groupName, err)
 		}
-		providers = append(providers, list...)
+		if filterReg != nil {
+			pd := provider.NewFilterableProvider(groupName, list, filterReg)
+			providers = append(providers, pd)
+		} else {
+			providers = append(providers, list...)
+		}
 	}
 
 	var group C.ProxyAdapter

adapter/provider/provider.go

@@ -9,12 +9,17 @@ import (
 	"time"
 
 	"github.com/Dreamacro/clash/adapter"
+	"github.com/Dreamacro/clash/adapter/outbound"
+	"github.com/Dreamacro/clash/common/singledo"
 	C "github.com/Dreamacro/clash/constant"
 	types "github.com/Dreamacro/clash/constant/provider"
 
+	"github.com/samber/lo"
 	"gopkg.in/yaml.v3"
 )
 
+var reject = adapter.NewProxy(outbound.NewReject())
+
 const (
 	ReservedName = "default"
 )
@@ -231,3 +236,77 @@ func NewCompatibleProvider(name string, proxies []C.Proxy, hc *HealthCheck) (*Co
 	runtime.SetFinalizer(wrapper, stopCompatibleProvider)
 	return wrapper, nil
 }
+
+var _ types.ProxyProvider = (*FilterableProvider)(nil)
+
+type FilterableProvider struct {
+	name      string
+	providers []types.ProxyProvider
+	filterReg *regexp.Regexp
+	single    *singledo.Single
+}
+
+func (fp *FilterableProvider) MarshalJSON() ([]byte, error) {
+	return json.Marshal(map[string]any{
+		"name":        fp.Name(),
+		"type":        fp.Type().String(),
+		"vehicleType": fp.VehicleType().String(),
+		"proxies":     fp.Proxies(),
+	})
+}
+
+func (fp *FilterableProvider) Name() string {
+	return fp.name
+}
+
+func (fp *FilterableProvider) HealthCheck() {
+}
+
+func (fp *FilterableProvider) Update() error {
+	return nil
+}
+
+func (fp *FilterableProvider) Initial() error {
+	return nil
+}
+
+func (fp *FilterableProvider) VehicleType() types.VehicleType {
+	return types.Compatible
+}
+
+func (fp *FilterableProvider) Type() types.ProviderType {
+	return types.Proxy
+}
+
+func (fp *FilterableProvider) Proxies() []C.Proxy {
+	elm, _, _ := fp.single.Do(func() (any, error) {
+		proxies := lo.FlatMap(
+			fp.providers,
+			func(item types.ProxyProvider, _ int) []C.Proxy {
+				return lo.Filter(
+					item.Proxies(),
+					func(item C.Proxy, _ int) bool {
+						return fp.filterReg.MatchString(item.Name())
+					})
+			})
+
+		if len(proxies) == 0 {
+			proxies = append(proxies, reject)
+		}
+		return proxies, nil
+	})
+
+	return elm.([]C.Proxy)
+}
+
+func (fp *FilterableProvider) Touch() {
+}
+
+func NewFilterableProvider(name string, providers []types.ProxyProvider, filterReg *regexp.Regexp) *FilterableProvider {
+	return &FilterableProvider{
+		name:      name,
+		providers: providers,
+		filterReg: filterReg,
+		single:    singledo.NewSingle(time.Second * 10),
+	}
+}