Support regex matching with attr (#2258)

* Support regex matching with attr

* Add test case

* Optimizing regex parsing at core start

* simpliy

app/router/condition.go

@@ -1,6 +1,7 @@
 package router
 
 import (
+	"regexp"
 	"strings"
 
 	"github.com/xtls/xray-core/common/net"
@@ -282,18 +283,18 @@ func (m *ProtocolMatcher) Apply(ctx routing.Context) bool {
 }
 
 type AttributeMatcher struct {
-	configuredKeys map[string]string
+	configuredKeys map[string]*regexp.Regexp
 }
 
 // Match implements attributes matching.
 func (m *AttributeMatcher) Match(attrs map[string]string) bool {
-	// headers are insensitive most likely. So we do a convert
+	// header keys are case insensitive most likely. So we do a convert
 	httpHeaders := make(map[string]string)
 	for key, value := range attrs {
-		httpHeaders[strings.ToLower(key)] = strings.ToLower(value)
+		httpHeaders[strings.ToLower(key)] = value
 	}
-	for key, value := range m.configuredKeys {
-		if a, ok := httpHeaders[key]; !ok || !strings.Contains(a, value) {
+	for key, regex := range m.configuredKeys {
+		if a, ok := httpHeaders[key]; !ok || !regex.MatchString(a) {
 			return false
 		}
 	}

app/router/condition_test.go

@@ -319,6 +319,19 @@ func TestRoutingRule(t *testing.T) {
 				},
 			},
 		},
+		{
+			rule: &RoutingRule{
+				Attributes: map[string]string{
+					"Custom": "p([a-z]+)ch",
+				},
+			},
+			test: []ruleTest{
+				{
+					input:  withContent(&session.Content{Attributes: map[string]string{"custom": "peach"}}),
+					output: true,
+				},
+			},
+		},
 	}
 
 	for _, test := range cases {

app/router/config.go

@@ -1,6 +1,7 @@
 package router
 
 import (
+	"regexp"
 	"strings"
 
 	"github.com/xtls/xray-core/common/net"
@@ -145,9 +146,9 @@ func (rr *RoutingRule) BuildCondition() (Condition, error) {
 	}
 
 	if len(rr.Attributes) > 0 {
-		configuredKeys := make(map[string]string)
+		configuredKeys := make(map[string]*regexp.Regexp)
 		for key, value := range rr.Attributes {
-			configuredKeys[strings.ToLower(key)] = strings.ToLower(value)
+			configuredKeys[strings.ToLower(key)] = regexp.MustCompile(value)
 		}
 		conds.Add(&AttributeMatcher{configuredKeys})
 	}