feature: add support of URL struct tags in struct-tag rule (#1239)

rule/struct_tag.go

@@ -104,6 +104,7 @@ const (
 	keyJSON     = "json"
 	keyProtobuf = "protobuf"
 	keyRequired = "required"
+	keyURL      = "url"
 	keyXML      = "xml"
 	keyYAML     = "yaml"
 )
@@ -198,6 +199,11 @@ func (w lintStructTagRule) checkTaggedField(f *ast.Field) {
 			if tag.Name != "true" && tag.Name != "false" {
 				w.addFailure(f.Tag, "required should be 'true' or 'false'")
 			}
+		case keyURL:
+			msg, ok := w.checkURLTag(tag.Options)
+			if !ok {
+				w.addFailure(f.Tag, msg)
+			}
 		case keyXML:
 			msg, ok := w.checkXMLTag(tag.Options)
 			if !ok {
@@ -329,6 +335,29 @@ func (w lintStructTagRule) checkYAMLTag(options []string) (string, bool) {
 	return "", true
 }
 
+func (w lintStructTagRule) checkURLTag(options []string) (string, bool) {
+	var delimiter = ""
+	for _, opt := range options {
+		switch opt {
+		case "int", "omitempty", "numbered", "brackets":
+		case "unix", "unixmilli", "unixnano": // TODO : check that the field is of type time.Time
+		case "comma", "semicolon", "space":
+			if delimiter == "" {
+				delimiter = opt
+				continue
+			}
+			return fmt.Sprintf("can not set both '%s' and '%s' as delimiters in URL tag", opt, delimiter), false
+		default:
+			if w.isUserDefined(keyURL, opt) {
+				continue
+			}
+			return fmt.Sprintf("unknown option '%s' in URL tag", opt), false
+		}
+	}
+
+	return "", true
+}
+
 func (lintStructTagRule) typeValueMatch(t ast.Expr, val string) bool {
 	tID, ok := t.(*ast.Ident)
 	if !ok {