initial translation/custom error code

Author: Dean Karn

errors.go

@@ -5,12 +5,16 @@ import (
 	"fmt"
 	"reflect"
 	"strings"
+
+	"github.com/go-playground/universal-translator"
 )
 
 const (
 	fieldErrMsg = "Key: '%s' Error:Field validation for '%s' failed on the '%s' tag"
 )
 
+type ValidationErrorsTranslations map[string]string
+
 // InvalidValidationError describes an invalid argument passed to
 // `Struct`, `StructExcept`, StructPartial` or `Field`
 type InvalidValidationError struct {
@@ -39,18 +43,32 @@ func (ve ValidationErrors) Error() string {
 
 	buff := bytes.NewBufferString("")
 
-	var err *fieldError
+	var fe *fieldError
 
 	for i := 0; i < len(ve); i++ {
 
-		err = ve[i].(*fieldError)
-		buff.WriteString(err.Error())
+		fe = ve[i].(*fieldError)
+		buff.WriteString(fe.Error())
 		buff.WriteString("\n")
 	}
 
 	return strings.TrimSpace(buff.String())
 }
 
+func (ve ValidationErrors) Translate(ut ut.Translator) ValidationErrorsTranslations {
+
+	trans := make(ValidationErrorsTranslations)
+
+	var fe *fieldError
+
+	for i := 0; i < len(ve); i++ {
+		fe = ve[i].(*fieldError)
+		trans[fe.ns] = fe.Translate(ut)
+	}
+
+	return trans
+}
+
 // FieldError contains all functions to get error details
 type FieldError interface {
 
@@ -118,6 +136,13 @@ type FieldError interface {
 	//
 	// // eg. time.Time's type is time.Time
 	Type() reflect.Type
+
+	// returns the FieldError's translated error
+	// from the provided 'ut.Translator' and registered 'TranslationFunc'
+	//
+	// NOTE: is not registered translation can be found it returns the same
+	// as calling fe.Error()
+	Translate(ut ut.Translator) string
 }
 
 // compile time interface checks
@@ -128,6 +153,7 @@ var _ error = new(fieldError)
 // with other properties that may be needed for error message creation
 // it complies with the FieldError interface
 type fieldError struct {
+	v              *Validate
 	tag            string
 	actualTag      string
 	ns             string
@@ -202,3 +228,23 @@ func (fe *fieldError) Type() reflect.Type {
 func (fe *fieldError) Error() string {
 	return fmt.Sprintf(fieldErrMsg, fe.ns, fe.Field(), fe.tag)
 }
+
+// Translate returns the FieldError's translated error
+// from the provided 'ut.Translator' and registered 'TranslationFunc'
+//
+// NOTE: is not registered translation can be found it returns the same
+// as calling fe.Error()
+func (fe *fieldError) Translate(ut ut.Translator) string {
+
+	m, ok := fe.v.transTagFunc[ut.Locale()]
+	if !ok {
+		return fe.Error()
+	}
+
+	fn, ok := m[fe.tag]
+	if !ok {
+		return fe.Error()
+	}
+
+	return fn(ut, fe)
+}

struct_level.go

@@ -117,6 +117,7 @@ func (v *validate) ReportError(field interface{}, fieldName, structFieldName, ta
 
 		v.errs = append(v.errs,
 			&fieldError{
+				v:              v.v,
 				tag:            tag,
 				actualTag:      tag,
 				ns:             v.str1,
@@ -132,6 +133,7 @@ func (v *validate) ReportError(field interface{}, fieldName, structFieldName, ta
 
 	v.errs = append(v.errs,
 		&fieldError{
+			v:              v.v,
 			tag:            tag,
 			actualTag:      tag,
 			ns:             v.str1,

translations.go

@@ -0,0 +1,11 @@
+package validator
+
+import "github.com/go-playground/universal-translator"
+
+// TranslationFunc is the function type used to register or override
+// custom translations
+type TranslationFunc func(ut ut.Translator, fe FieldError) string
+
+// RegisterTranslationsFunc allows for registering of translations
+// for a 'ut.Translator' for use withing the 'TranslationFunc'
+type RegisterTranslationsFunc func(ut ut.Translator) error

validator.go

@@ -113,6 +113,7 @@ func (v *validate) traverseField(parent reflect.Value, current reflect.Value, ns
 
 				v.errs = append(v.errs,
 					&fieldError{
+						v:              v.v,
 						tag:            ct.aliasTag,
 						actualTag:      ct.tag,
 						ns:             v.str1,
@@ -129,6 +130,7 @@ func (v *validate) traverseField(parent reflect.Value, current reflect.Value, ns
 
 			v.errs = append(v.errs,
 				&fieldError{
+					v:              v.v,
 					tag:            ct.aliasTag,
 					actualTag:      ct.tag,
 					ns:             v.str1,
@@ -323,6 +325,7 @@ OUTER:
 
 						v.errs = append(v.errs,
 							&fieldError{
+								v:              v.v,
 								tag:            ct.aliasTag,
 								actualTag:      ct.actualAliasTag,
 								ns:             v.str1,
@@ -342,6 +345,7 @@ OUTER:
 
 						v.errs = append(v.errs,
 							&fieldError{
+								v:              v.v,
 								tag:            tVal,
 								actualTag:      tVal,
 								ns:             v.str1,
@@ -381,6 +385,7 @@ OUTER:
 
 				v.errs = append(v.errs,
 					&fieldError{
+						v:              v.v,
 						tag:            ct.aliasTag,
 						actualTag:      ct.tag,
 						ns:             v.str1,

validator_instance.go

@@ -7,6 +7,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/go-playground/universal-translator"
 )
 
 const (
@@ -53,6 +55,7 @@ type Validate struct {
 	customFuncs      map[reflect.Type]CustomTypeFunc
 	aliases          map[string]string
 	validations      map[string]Func
+	transTagFunc     map[string]map[string]TranslationFunc // map[<locale>]map[<tag>]TranslationFunc
 	tagCache         *tagCache
 	structCache      *structCache
 }
@@ -189,6 +192,27 @@ func (v *Validate) RegisterCustomTypeFunc(fn CustomTypeFunc, types ...interface{
 	v.hasCustomFuncs = true
 }
 
+func (v *Validate) RegisterTranslation(tag string, ut ut.Translator, registerFn RegisterTranslationsFunc, translationFn TranslationFunc) (err error) {
+
+	if v.transTagFunc == nil {
+		v.transTagFunc = make(map[string]map[string]TranslationFunc)
+	}
+
+	if err = registerFn(ut); err != nil {
+		return
+	}
+
+	m, ok := v.transTagFunc[ut.Locale()]
+	if !ok {
+		m = make(map[string]TranslationFunc)
+		v.transTagFunc[ut.Locale()] = m
+	}
+
+	m[tag] = translationFn
+
+	return
+}
+
 // Struct validates a structs exposed fields, and automatically validates nested structs, unless otherwise specified.
 //
 // It returns InvalidValidationError for bad values passed in and nil or ValidationErrors as error otherwise.

validator_test.go

@@ -11,6 +11,11 @@ import (
 	"time"
 
 	. "gopkg.in/go-playground/assert.v1"
+
+	"github.com/go-playground/locales/en"
+	"github.com/go-playground/locales/fr"
+	"github.com/go-playground/locales/nl"
+	"github.com/go-playground/universal-translator"
 )
 
 // NOTES:
@@ -6413,3 +6418,145 @@ func TestRequired(t *testing.T) {
 	NotEqual(t, err, nil)
 	AssertError(t, err.(ValidationErrors), "Test.Value", "Test.Value", "Value", "Value", "required")
 }
+
+func TestTranslations(t *testing.T) {
+	en := en.New()
+	uni := ut.New(en, en, fr.New())
+
+	trans, _ := uni.GetTranslator("en")
+	fr, _ := uni.GetTranslator("fr")
+
+	validate := New()
+	err := validate.RegisterTranslation("required", trans,
+		func(ut ut.Translator) (err error) {
+
+			// using this stype because multiple translation may have to be added for the full translation
+			if err = ut.Add("required", "{0} is a required field", false); err != nil {
+				return
+			}
+
+			return
+
+		}, func(ut ut.Translator, fe FieldError) string {
+
+			t, err := ut.T(fe.Tag(), fe.Field())
+			if err != nil {
+				fmt.Printf("warning: error translating FieldError: %#v", fe.(*fieldError))
+				return fe.(*fieldError).Error()
+			}
+
+			return t
+		})
+	Equal(t, err, nil)
+
+	err = validate.RegisterTranslation("required", fr,
+		func(ut ut.Translator) (err error) {
+
+			// using this stype because multiple translation may have to be added for the full translation
+			if err = ut.Add("required", "{0} est un champ obligatoire", false); err != nil {
+				return
+			}
+
+			return
+
+		}, func(ut ut.Translator, fe FieldError) string {
+
+			t, err := ut.T(fe.Tag(), fe.Field())
+			if err != nil {
+				fmt.Printf("warning: error translating FieldError: %#v", fe.(*fieldError))
+				return fe.(*fieldError).Error()
+			}
+
+			return t
+		})
+
+	Equal(t, err, nil)
+
+	type Test struct {
+		Value interface{} `validate:"required"`
+	}
+
+	var test Test
+
+	err = validate.Struct(test)
+	NotEqual(t, err, nil)
+
+	errs := err.(ValidationErrors)
+	Equal(t, len(errs), 1)
+
+	fe := errs[0]
+	Equal(t, fe.Tag(), "required")
+	Equal(t, fe.Namespace(), "Test.Value")
+	Equal(t, fe.Translate(trans), fmt.Sprintf("%s is a required field", fe.Field()))
+	Equal(t, fe.Translate(fr), fmt.Sprintf("%s est un champ obligatoire", fe.Field()))
+
+	nl := nl.New()
+	uni2 := ut.New(nl, nl)
+	trans2, _ := uni2.GetTranslator("nl")
+	Equal(t, fe.Translate(trans2), "Key: 'Test.Value' Error:Field validation for 'Value' failed on the 'required' tag")
+
+	terrs := errs.Translate(trans)
+	Equal(t, len(terrs), 1)
+
+	v, ok := terrs["Test.Value"]
+	Equal(t, ok, true)
+	Equal(t, v, fmt.Sprintf("%s is a required field", fe.Field()))
+
+	terrs = errs.Translate(fr)
+	Equal(t, len(terrs), 1)
+
+	v, ok = terrs["Test.Value"]
+	Equal(t, ok, true)
+	Equal(t, v, fmt.Sprintf("%s est un champ obligatoire", fe.Field()))
+
+	type Test2 struct {
+		Value string `validate:"gt=1"`
+	}
+
+	var t2 Test2
+
+	err = validate.Struct(t2)
+	NotEqual(t, err, nil)
+
+	errs = err.(ValidationErrors)
+	Equal(t, len(errs), 1)
+
+	fe = errs[0]
+	Equal(t, fe.Tag(), "gt")
+	Equal(t, fe.Namespace(), "Test2.Value")
+	Equal(t, fe.Translate(trans), "Key: 'Test2.Value' Error:Field validation for 'Value' failed on the 'gt' tag")
+}
+
+func TestTranslationErrors(t *testing.T) {
+
+	en := en.New()
+	uni := ut.New(en, en, fr.New())
+
+	trans, _ := uni.GetTranslator("en")
+	trans.Add("required", "{0} is a required field", false) // using translator outside of validator also
+
+	validate := New()
+	err := validate.RegisterTranslation("required", trans,
+		func(ut ut.Translator) (err error) {
+
+			// using this stype because multiple translation may have to be added for the full translation
+			if err = ut.Add("required", "{0} is a required field", false); err != nil {
+				return
+			}
+
+			return
+
+		}, func(ut ut.Translator, fe FieldError) string {
+
+			t, err := ut.T(fe.Tag(), fe.Field())
+			if err != nil {
+				fmt.Printf("warning: error translating FieldError: %#v", fe.(*fieldError))
+				return fe.(*fieldError).Error()
+			}
+
+			return t
+		})
+
+	NotEqual(t, err, nil)
+	Equal(t, err.Error(), "error: conflicting key 'required' rule 'Unknown' with text '{0} is a required field', value being ignored")
+}