init commit

core/parser.go

@@ -0,0 +1,177 @@
+package core
+
+import (
+	"fmt"
+	"net/url"
+	"strconv"
+	"strings"
+)
+
+// ParseLink parses a VPN link and returns a ProxyLink.
+// Supported protocols: trojan, vless.
+func ParseLink(link string) (*ProxyLink, error) {
+	link = strings.TrimSpace(link)
+	if link == "" {
+		return nil, fmt.Errorf("link cannot be empty")
+	}
+
+	protocol, err := getProtocol(link)
+	if err != nil {
+		return nil, err
+	}
+
+	switch protocol {
+	case "trojan", "vless":
+		return parseTrojanOrVless(link, protocol)
+	default:
+		return nil, fmt.Errorf("unsupported protocol: %s", protocol)
+	}
+}
+
+// TryParseLink attempts to parse a VPN link, returning nil on failure.
+func TryParseLink(link string) *ProxyLink {
+	result, err := ParseLink(link)
+	if err != nil {
+		return nil
+	}
+	return result
+}
+
+func getProtocol(link string) (string, error) {
+	idx := strings.Index(link, "://")
+	if idx < 0 {
+		return "", fmt.Errorf("invalid link format: scheme (protocol://) is missing")
+	}
+	return strings.ToLower(link[:idx]), nil
+}
+
+// parseTrojanOrVless parses links of format: protocol://credential@host:port?params#remark
+func parseTrojanOrVless(link, protocol string) (*ProxyLink, error) {
+	result := &ProxyLink{
+		Protocol:    protocol,
+		Security:    "none",
+		Fingerprint: "chrome",
+		Transport:   "tcp",
+	}
+
+	// Remove scheme
+	remainder := link[len(protocol)+3:]
+
+	// Extract fragment (#remark)
+	if fragmentIdx := strings.LastIndex(remainder, "#"); fragmentIdx >= 0 {
+		decoded, err := url.PathUnescape(remainder[fragmentIdx+1:])
+		if err != nil {
+			result.Remark = remainder[fragmentIdx+1:]
+		} else {
+			result.Remark = decoded
+		}
+		remainder = remainder[:fragmentIdx]
+	}
+
+	// Extract query string (?params)
+	var queryParams url.Values
+	if queryIdx := strings.Index(remainder, "?"); queryIdx >= 0 {
+		var err error
+		queryParams, err = url.ParseQuery(remainder[queryIdx+1:])
+		if err != nil {
+			queryParams = url.Values{}
+		}
+		remainder = remainder[:queryIdx]
+	} else {
+		queryParams = url.Values{}
+	}
+
+	// Extract credential@host:port
+	atIdx := strings.Index(remainder, "@")
+	if atIdx < 0 {
+		return nil, fmt.Errorf("invalid format: missing credential@host:port")
+	}
+
+	decoded, err := url.PathUnescape(remainder[:atIdx])
+	if err != nil {
+		result.Credential = remainder[:atIdx]
+	} else {
+		result.Credential = decoded
+	}
+
+	hostPort := remainder[atIdx+1:]
+
+	// Parse host:port
+	if err := parseHostPort(hostPort, result); err != nil {
+		return nil, err
+	}
+
+	// Parse query parameters
+	parseQueryParams(queryParams, result)
+
+	return result, nil
+}
+
+func parseHostPort(hostPort string, result *ProxyLink) error {
+	var lastColon int
+
+	if strings.HasPrefix(hostPort, "[") {
+		// IPv6: [::1]:443
+		bracketEnd := strings.Index(hostPort, "]")
+		if bracketEnd < 0 {
+			return fmt.Errorf("invalid IPv6 address: missing closing bracket")
+		}
+		result.Address = hostPort[1:bracketEnd]
+		lastColon = strings.Index(hostPort[bracketEnd:], ":")
+		if lastColon >= 0 {
+			lastColon += bracketEnd
+		}
+	} else {
+		lastColon = strings.LastIndex(hostPort, ":")
+		if lastColon < 0 {
+			return fmt.Errorf("invalid format: missing port")
+		}
+		result.Address = hostPort[:lastColon]
+	}
+
+	if lastColon < 0 || lastColon >= len(hostPort)-1 {
+		return fmt.Errorf("invalid format: missing port")
+	}
+
+	portStr := hostPort[lastColon+1:]
+	port, err := strconv.Atoi(portStr)
+	if err != nil || port < 1 || port > 65535 {
+		return fmt.Errorf("invalid port: %s", portStr)
+	}
+	result.Port = port
+
+	return nil
+}
+
+func parseQueryParams(params url.Values, result *ProxyLink) {
+	if v := params.Get("security"); v != "" {
+		result.Security = strings.ToLower(v)
+	}
+	if v := params.Get("sni"); v != "" {
+		result.Sni = v
+	}
+	if v := params.Get("fp"); v != "" {
+		result.Fingerprint = v
+	}
+	if v := params.Get("pbk"); v != "" {
+		result.PublicKey = v
+	}
+	if v := params.Get("sid"); v != "" {
+		result.ShortId = v
+	}
+	if v := params.Get("type"); v != "" {
+		result.Transport = strings.ToLower(v)
+	}
+	if v := params.Get("serviceName"); v != "" {
+		result.ServiceName = v
+	}
+	if v := params.Get("path"); v != "" {
+		result.Path = v
+	}
+	if v := params.Get("host"); v != "" {
+		result.Host = v
+	}
+	if v := params.Get("flow"); v != "" {
+		result.Flow = v
+	}
+}