feat(lagoon): accept string and url rules in lagoon.Validate (quick-261104-f4x)

- string requires a string value (pointers and named string types
  included), url a URL matching Laravel's pattern (urlPattern, shared
  with lagoon.ValidateRequest); both skip an empty or blank value
- lagoon::validate.string and .url in the en and pl catalogs, English
  fallbacks for a nil translator
- settings saves whose model rules use nullable|string|max:255 or
  nullable|url|max:500 no longer fail with an unrecognized-rule error

modules/lagoon/validate.go

@@ -51,6 +51,8 @@ func validateField(ctx context.Context, tx *gorm.DB, model any, field, rule stri
 	var betweenMin, betweenMax, minArg, maxArg string
 	hasNumeric := false
 	hasInteger := false
+	hasString := false
+	hasURL := false
 	for _, tok := range tokens {
 		name, arg, _ := strings.Cut(tok, ":")
 		switch name {
@@ -87,6 +89,10 @@ func validateField(ctx context.Context, tx *gorm.DB, model any, field, rule stri
 			}
 		case "email":
 			tags = append(tags, "email")
+		case "string":
+			hasString = true
+		case "url":
+			hasURL = true
 		case "confirmed":
 			if fmt.Sprint(val) != fmt.Sprint(values[field+"_confirmation"]) {
 				return []string{validateMessage(ctx, tr, "confirmed", field, nil)}, nil
@@ -155,6 +161,23 @@ func validateField(ctx context.Context, tx *gorm.DB, model any, field, rule stri
 	if required && isEmptyValue(val) {
 		return []string{validateMessage(ctx, tr, "required", field, nil)}, nil
 	}
+	if hasString || hasURL {
+		// Like Laravel, string and url skip a blank value; required has
+		// already handled emptiness.
+		s, isStr := ruleString(val)
+		if !isEmptyValue(val) && (!isStr || strings.TrimSpace(s) != "") {
+			if hasString && !isStr {
+				return []string{validateMessage(ctx, tr, "string", field, nil)}, nil
+			}
+			var msgs []string
+			if hasURL && (!isStr || !urlPattern.MatchString(s)) {
+				msgs = append(msgs, validateMessage(ctx, tr, "url", field, nil))
+			}
+			if len(msgs) > 0 {
+				return msgs, nil
+			}
+		}
+	}
 	usedBetween := betweenMin != "" && betweenMax != ""
 	if len(tags) > 0 {
 		msgs := make([]string, 0, len(tags))
@@ -327,6 +350,26 @@ func isIntegerValue(val any) bool {
 	}
 }
 
+// ruleString answers the string a string or url rule checks: it
+// dereferences pointers and interfaces (a nil one is no string) and accepts
+// any value whose kind is string, named string types included.
+func ruleString(val any) (string, bool) {
+	if val == nil {
+		return "", false
+	}
+	rv := reflect.ValueOf(val)
+	for rv.Kind() == reflect.Ptr || rv.Kind() == reflect.Interface {
+		if rv.IsNil() {
+			return "", false
+		}
+		rv = rv.Elem()
+	}
+	if rv.Kind() != reflect.String {
+		return "", false
+	}
+	return rv.String(), true
+}
+
 func numericString(val any) (string, bool) {
 	if val == nil {
 		return "", false
@@ -466,6 +509,10 @@ func validateMessage(ctx context.Context, tr *phrasebook.Translator, rule, field
 		return "The " + attr + " must be between " + params["min"] + " and " + params["max"] + "."
 	case "boolean":
 		return "The " + attr + " field must be true or false."
+	case "string":
+		return "The " + attr + " must be a string."
+	case "url":
+		return "The " + attr + " format is invalid."
 	default:
 		return "The " + attr + " is invalid."
 	}