snapshot of https://github.com/livekit/livekit.git @ 08c5433449c106943231037d0b892895f6e92d3b (2026-09-15)

pkg/clientconfiguration/match.go

@@ -0,0 +1,177 @@
+// Copyright 2023 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package clientconfiguration
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/d5/tengo/v2"
+	"github.com/d5/tengo/v2/token"
+	"golang.org/x/mod/semver"
+
+	"github.com/livekit/protocol/livekit"
+)
+
+type Match interface {
+	Match(clientInfo *livekit.ClientInfo) (bool, error)
+}
+
+type ScriptMatch struct {
+	compiled *tengo.Compiled
+}
+
+func NewScriptMatch(expr string) (*ScriptMatch, error) {
+	script := tengo.NewScript(fmt.Appendf(nil, "__res__ := (%s)", expr))
+	if err := script.Add("c", &clientObject{}); err != nil {
+		return nil, err
+	}
+	compiled, err := script.Compile()
+	if err != nil {
+		return nil, err
+	}
+	return &ScriptMatch{compiled}, nil
+}
+
+// use result of eval script expression for match.
+// expression examples:
+// protocol bigger than 5 : c.protocol > 5
+// browser if firefox: c.browser == "firefox"
+// combined rule : c.protocol > 5 && c.browser == "firefox"
+func (m *ScriptMatch) Match(clientInfo *livekit.ClientInfo) (bool, error) {
+	clone := m.compiled.Clone()
+	if err := clone.Set("c", &clientObject{info: clientInfo}); err != nil {
+		return false, err
+	}
+	if err := clone.Run(); err != nil {
+		return false, err
+	}
+
+	res := clone.Get("__res__").Value()
+	if val, ok := res.(bool); ok {
+		return val, nil
+	}
+	return false, errors.New("invalid match expression result")
+}
+
+// ------------------------------------------------
+
+type clientObject struct {
+	tengo.ObjectImpl
+	info *livekit.ClientInfo
+}
+
+func (c *clientObject) TypeName() string {
+	return "clientObject"
+}
+
+func (c *clientObject) String() string {
+	return c.info.String()
+}
+
+func (c *clientObject) IndexGet(index tengo.Object) (res tengo.Object, err error) {
+	field, ok := index.(*tengo.String)
+	if !ok {
+		return nil, tengo.ErrInvalidIndexType
+	}
+
+	switch field.Value {
+	case "sdk":
+		return &tengo.String{Value: strings.ToLower(c.info.Sdk.String())}, nil
+	case "version":
+		return &ruleSdkVersion{sdkVersion: c.info.Version}, nil
+	case "protocol":
+		return &tengo.Int{Value: int64(c.info.Protocol)}, nil
+	case "os":
+		return &tengo.String{Value: strings.ToLower(c.info.Os)}, nil
+	case "os_version":
+		return &tengo.String{Value: c.info.OsVersion}, nil
+	case "device_model":
+		return &tengo.String{Value: strings.ToLower(c.info.DeviceModel)}, nil
+	case "browser":
+		return &tengo.String{Value: strings.ToLower(c.info.Browser)}, nil
+	case "browser_version":
+		return &ruleSdkVersion{sdkVersion: c.info.BrowserVersion}, nil
+	case "address":
+		return &tengo.String{Value: c.info.Address}, nil
+	}
+	return &tengo.Undefined{}, nil
+}
+
+// ------------------------------------------
+
+type ruleSdkVersion struct {
+	tengo.ObjectImpl
+	sdkVersion string
+}
+
+func (r *ruleSdkVersion) TypeName() string {
+	return "sdkVersion"
+}
+
+func (r *ruleSdkVersion) String() string {
+	return r.sdkVersion
+}
+
+func (r *ruleSdkVersion) BinaryOp(op token.Token, rhs tengo.Object) (tengo.Object, error) {
+	if rhs, ok := rhs.(*tengo.String); ok {
+		cmp := r.compare(rhs.Value)
+
+		isMatch := false
+		switch op {
+		case token.Greater:
+			isMatch = cmp > 0
+		case token.GreaterEq:
+			isMatch = cmp >= 0
+		case token.Less:
+			isMatch = cmp < 0
+		case token.LessEq:
+			isMatch = cmp <= 0
+		default:
+			return nil, tengo.ErrInvalidOperator
+		}
+
+		if isMatch {
+			return tengo.TrueValue, nil
+		}
+		return tengo.FalseValue, nil
+	}
+
+	return nil, tengo.ErrInvalidOperator
+}
+
+func (r *ruleSdkVersion) Equals(rhs tengo.Object) bool {
+	if rhs, ok := rhs.(*tengo.String); ok {
+		return r.compare(rhs.Value) == 0
+	}
+
+	return false
+}
+
+func (r *ruleSdkVersion) compare(rhsSdkVersion string) int {
+	if !semver.IsValid("v"+r.sdkVersion) || !semver.IsValid("v"+rhsSdkVersion) {
+		// if not valid semver, do string compare
+		switch {
+		case r.sdkVersion < rhsSdkVersion:
+			return -1
+		case r.sdkVersion > rhsSdkVersion:
+			return 1
+		}
+	} else {
+		return semver.Compare("v"+r.sdkVersion, "v"+rhsSdkVersion)
+	}
+	return 0
+}