sub: add support for custom subscription headers

service/setting.go

@@ -91,6 +91,7 @@ var defaultValueMap = map[string]string{
 	"subURI":             "",
 	"subJsonExt":         "",
 	"subClashExt":        "",
+	"subCustomHeaders":   defaultCustomHeaders,
 	"subClashNoDefGrp":   "false",
 	"subClashSprtAll":    "false",
 	"subClashUdp":        "false",
@@ -540,6 +541,10 @@ func (s *SettingService) GetSubClashExt() (string, error) {
 	return s.getString("subClashExt")
 }
 
+func (s *SettingService) GetSubCustomHeaders() (string, error) {
+	return s.getString("subCustomHeaders")
+}
+
 // GetSubClashNoDefGrp reports whether the default "Proxy"/"Auto" proxy-groups
 // should never be injected into a Clash subscription. When true, the config is
 // left with exactly the groups the user defined.
@@ -576,3 +581,13 @@ func (s *SettingService) fileExists(path string) error {
 	_, err := os.Stat(path)
 	return err
 }
+
+var defaultCustomHeaders = `# Custom Subscription Headers
+# Syntax:
+# Header-Name: Value
+#
+# Lines starting with # are comments and will be ignored.
+#
+# Example:
+# announce: 42!
+# announce-url: https://42.example/`

sub/subHandler.go

@@ -79,6 +79,52 @@ func (s *SubHandler) addHeaders(c *gin.Context, headers []string) {
 	c.Writer.Header().Set("Profile-Update-Interval", headers[1])
 	c.Writer.Header().Set("Profile-Title", headers[2])
 	c.Writer.Header().Set("Content-Disposition", contentDispositionHeader(headers[2]))
+
+	s.applyCustomHeaders(c)
+}
+
+type customHeader struct {
+	key   string
+	value string
+}
+
+func parseCustomHeaders(raw string) []customHeader {
+	if len(strings.TrimSpace(raw)) == 0 {
+		return nil
+	}
+
+	var headers []customHeader
+	lines := strings.Split(strings.ReplaceAll(raw, "\r\n", "\n"), "\n")
+	for _, line := range lines {
+		line = strings.TrimSpace(line)
+		if line == "" || strings.HasPrefix(line, "#") || strings.HasPrefix(line, "//") {
+			continue
+		}
+
+		parts := strings.SplitN(line, ":", 2)
+		if len(parts) != 2 {
+			continue
+		}
+
+		key := strings.TrimSpace(parts[0])
+		val := strings.TrimSpace(parts[1])
+
+		if key != "" && val != "" {
+			headers = append(headers, customHeader{key: key, value: val})
+		}
+	}
+	return headers
+}
+
+func (s *SubHandler) applyCustomHeaders(c *gin.Context) {
+	customHeadersStr, err := s.SettingService.GetSubCustomHeaders()
+	if err != nil {
+		return
+	}
+
+	for _, h := range parseCustomHeaders(customHeadersStr) {
+		c.Writer.Header().Set(h.key, h.value)
+	}
 }
 
 func contentDispositionHeader(name string) string {

sub/subHandler_test.go

@@ -0,0 +1,78 @@
+package sub
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseCustomHeaders(t *testing.T) {
+	testCases := []struct {
+		name string
+		in   string
+		want []customHeader
+	}{
+		{
+			name: "empty string",
+			in:   "",
+			want: nil,
+		},
+		{
+			name: "whitespace only",
+			in:   "   \n\t  \r\n   ",
+			want: nil,
+		},
+		{
+			name: "comments test",
+			in:   `# 424242`,
+			want: nil,
+		},
+		{
+			name: "valid headers with extra spaces",
+			in: `
+			announce :  42! 
+			announce-url: t.me/4242
+			`,
+			want: []customHeader{
+				{key: "announce", value: "42!"},
+				{key: "announce-url", value: "t.me/4242"},
+			},
+		},
+		{
+			name: "urls containing colons and ports are preserved",
+			in:   "Profile-Web-Page-Url: https://sub.example.com:8443/login?redirect=https://a.com",
+			want: []customHeader{
+				{key: "Profile-Web-Page-Url", value: "https://sub.example.com:8443/login?redirect=https://a.com"},
+			},
+		},
+		{
+			name: "windows crlf line endings and inline comments",
+			in:   "# header 1\r\nX-Custom: value1\r\n// comment 2\r\nX-Other: value2\r\n",
+			want: []customHeader{
+				{key: "X-Custom", value: "value1"},
+				{key: "X-Other", value: "value2"},
+			},
+		},
+		{
+			name: "malformed lines are safely skipped without panic",
+			in: `
+random text without colon
+: missing key
+empty value: 
+:
+valid-key: ok
+`,
+			want: []customHeader{
+				{key: "valid-key", value: "ok"},
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := parseCustomHeaders(tc.in)
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("parseCustomHeaders() mismatch for %q:\n got:  %+v\n want: %+v", tc.name, got, tc.want)
+			}
+		})
+	}
+}