added email validation for strings

Author: Yury Miadzelets

examples/translation/main.go

@@ -18,6 +18,8 @@ type Sender struct {
 	SMTPPort      string
 	HTTPAddress   string
 	HTTPDestParam string
+	Email         string
+	Emails        []string
 	Description   *string
 	Int           int
 	Id            uuid.UUID
@@ -50,6 +52,8 @@ func main() {
 		builder.String(&obj.SMTPHost).Trim().
 			Regexp(regexp.MustCompile("^[a-zA-Z0-9.]+$"), str.WithRegexpLocaleKey(customRegexpLocaleKey))
 		builder.UUID(&obj.Id).Required()
+		builder.String(&obj.Email).Email()
+		builder.StringSlice(&obj.Emails).Email()
 		builder.String(&obj.Description).Trim()
 		builder.StringSlice(&obj.Templates).Trim().
 			Regexp(regexp.MustCompile("^[a-zA-Z0-9.]+$"), str.WithRegexpLocaleKey(customRegexpLocaleKey))
@@ -67,6 +71,8 @@ func main() {
 		SMTPPort:      uuid.New().String() + " ",
 		HTTPAddress:   uuid.New().String() + " ",
 		HTTPDestParam: uuid.New().String() + "  ",
+		Email:         "correct@email.com",
+		Emails:        []string{"correct@email.com", "incorrect.email.com"},
 		Id:            id,
 		Int:           2,
 	}

str/base.go

@@ -16,6 +16,9 @@ const (
 	requiredLocaleKey  = "validation:string:Should be fulfilled"
 	regexpLocaleKey    = "validation:string:Doesn't match required regexp pattern"
 	anyOfLocaleKey     = "validation:string:Only %s values is allowed"
+	emailLocaleKey     = "validation:string:Should be email address"
+
+	emailRegexp = `^[^\s,@#$%^&*!()]+@([a-zA-Z0-9]+[.])+[a-zA-Z]{2,8}$`
 )
 
 type baseConfigurator[T strPtr] struct {
@@ -93,6 +96,15 @@ func (i *baseConfigurator[T]) AnyOf(allowed ...string) BaseConfigurator {
 	return i
 }
 
+// Email checks is the string value is email.
+func (i *baseConfigurator[T]) Email() BaseConfigurator {
+	i.c.Append(func(v T) bool {
+		r := regexp.MustCompile(emailRegexp)
+		return r.MatchString(*v)
+	}, emailLocaleKey)
+	return i
+}
+
 // When allows for conditional validation logic to be applied to the string value.
 func (i *baseConfigurator[T]) When(whenFn func(ctx context.Context, value any) bool) BaseConfigurator {
 	if whenFn == nil {

str/slice.go

@@ -52,3 +52,19 @@ func (s *StringSliceFieldConfigurator) Regexp(regexp *regexp.Regexp, opts ...Reg
 	})
 	return s
 }
+
+func (s *StringSliceFieldConfigurator) Email() *StringSliceFieldConfigurator {
+	s.Custom(func(ctx context.Context, h *shared.FieldCustomHelper, v []*any) []shared.Error {
+		values := shared.UnsafeValigoSliceCast[string](v)
+		var errs []shared.Error
+		r := regexp.MustCompile(emailRegexp)
+		for _, val := range values {
+			if !r.MatchString(*val) {
+				errs = append(errs, h.ErrorT(ctx, *val, emailLocaleKey))
+			}
+		}
+
+		return errs
+	})
+	return s
+}

str/types.go

@@ -28,6 +28,9 @@ type BaseConfigurator interface {
 	// MinLen checks if the string length is not less than the given minimum length.
 	MinLen(int) BaseConfigurator
 
+	// Email checks is the string is email address
+	Email() BaseConfigurator
+
 	// When allows for conditional validation based on a given condition.
 	When(whenFn func(ctx context.Context, value any) bool) BaseConfigurator
 }

translator/locales/en/data.yaml

@@ -6,6 +6,7 @@ validation:
     "Cannot be shorter than %d characters": Cannot be shorter than %d characters
     "Doesn't match required regexp pattern": Doesn't match required regexp pattern
     "Only %s values is allowed": Only %s values is allowed
+    "Should be email address": Should be email address
   num:
     "Cannot be less than %v": Cannot be less than %v
     "Cannot be greater than %v": Cannot be greater than %v

translator/locales/ru/data.yaml

@@ -6,6 +6,7 @@ validation:
     "Cannot be shorter than %d characters": Не может быть короче %d символов
     "Doesn't match required regexp pattern": Не соответствует regexp шаблону
     "Only %s values is allowed": Только %s значения разрешены
+    "Should be email address": Должно быть электронным адресом
   num:
     "Cannot be less than %v": Не может быть меньше %v
     "Cannot be greater than %v": Не может быть больше %v