initial commit

internal/validation/custom_validation.go

@@ -0,0 +1,83 @@
+package validation
+
+import (
+	"reflect"
+	"regexp"
+	"strings"
+
+	"github.com/go-playground/validator/v10"
+)
+
+var (
+	reUpper = regexp.MustCompile(`[A-Z]`)
+	reLower = regexp.MustCompile(`[a-z]`)
+	reDigit = regexp.MustCompile(`[0-9]`)
+	reSym   = regexp.MustCompile(`[^A-Za-z0-9]`)
+)
+
+func Password(fl validator.FieldLevel) bool {
+	pw := fl.Field().String()
+	pw = strings.TrimSpace(pw)
+
+	if len(pw) < 8 {
+		return false
+	}
+	if !reUpper.MatchString(pw) {
+		return false
+	}
+	if !reLower.MatchString(pw) {
+		return false
+	}
+	if !reDigit.MatchString(pw) {
+		return false
+	}
+	if !reSym.MatchString(pw) {
+		return false
+	}
+	if strings.Contains(pw, " ") {
+		return false
+	}
+
+	parent := fl.Parent()
+	if parent.IsValid() && parent.Kind() == reflect.Struct {
+		emailField := parent.FieldByName("Email")
+		if emailField.IsValid() && emailField.Kind() == reflect.String {
+			if email := emailField.String(); email != "" {
+				if i := strings.IndexByte(email, '@'); i > 0 {
+					local := strings.ToLower(email[:i])
+					if local != "" && strings.Contains(strings.ToLower(pw), local) {
+						return false
+					}
+				}
+			}
+		}
+	}
+	return true
+}
+
+func RequiredStrict(fl validator.FieldLevel) bool {
+	field := fl.Field()
+
+	switch field.Kind() {
+	case reflect.String:
+		return field.String() != ""
+	case reflect.Ptr:
+		return !field.IsNil()
+	}
+
+	return field.IsValid() && !field.IsZero()
+}
+
+func OmitemptyStrict(fl validator.FieldLevel) bool {
+	field := fl.Field()
+
+	if !field.IsValid() || field.IsZero() {
+		return true
+	}
+
+	if field.Kind() == reflect.String {
+		return field.String() != ""
+	}
+
+	return true
+}

internal/validation/validation.go

@@ -0,0 +1,75 @@
+package validation
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/go-playground/validator/v10"
+)
+
+var customMessages = map[string]string{
+	"required":         "Field %s is required",
+	"required_strict":  "Field %s is required and cannot be null or empty",
+	"omitempty_strict": "Field %s cannot be null or empty when provided",
+
+	"email":    "Invalid email address for field %s",
+	"min":      "Field %s must have a minimum length of %s characters",
+	"max":      "Field %s must have a maximum length of %s characters",
+	"len":      "Field %s must be exactly %s characters long",
+	"number":   "Field %s must be a number",
+	"positive": "Field %s must be a positive number",
+	"alphanum": "Field %s must contain only alphanumeric characters",
+	"oneof":    "Invalid value for field %s",
+	"password": "Field %s must be at least 8 characters, contain uppercase, lowercase, number, and special character",
+}
+
+func CustomErrorMessages(err error) map[string]string {
+	var validationErrors validator.ValidationErrors
+	if errors.As(err, &validationErrors) {
+		return generateErrorMessages(validationErrors)
+	}
+	return nil
+}
+
+func generateErrorMessages(validationErrors validator.ValidationErrors) map[string]string {
+	errorsMap := make(map[string]string)
+	for _, err := range validationErrors {
+		fieldName := err.StructNamespace()
+		tag := err.Tag()
+
+		customMessage := customMessages[tag]
+		if customMessage != "" {
+			errorsMap[fieldName] = formatErrorMessage(customMessage, err, tag)
+		} else {
+			errorsMap[fieldName] = defaultErrorMessage(err)
+		}
+	}
+	return errorsMap
+}
+
+func formatErrorMessage(customMessage string, err validator.FieldError, tag string) string {
+	if tag == "min" || tag == "max" || tag == "len" {
+		return fmt.Sprintf(customMessage, err.Field(), err.Param())
+	}
+	return fmt.Sprintf(customMessage, err.Field())
+}
+
+func defaultErrorMessage(err validator.FieldError) string {
+	return fmt.Sprintf("Field validation for '%s' failed on the '%s' tag", err.Field(), err.Tag())
+}
+
+func Validator() *validator.Validate {
+	validate := validator.New()
+
+	if err := validate.RegisterValidation("password", Password); err != nil {
+		return nil
+	}
+	if err := validate.RegisterValidation("required_strict", RequiredStrict); err != nil {
+		return nil
+	}
+	if err := validate.RegisterValidation("omitempty_strict", OmitemptyStrict); err != nil {
+		return nil
+	}
+
+	return validate
+}