fix(binding): Move validator engine getter inside interface

README.md

@@ -564,11 +564,11 @@ func bookableDate(
 
 func main() {
 	route := gin.Default()
-	v := binding.ValidatorEngine()
-	if v == nil {
-		panic("validator engine is nil")
+
+	if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
+		v.RegisterValidation("bookabledate", bookableDate)
 	}
-	v.RegisterValidation("bookabledate", bookableDate)
+
 	route.GET("/bookable", getBookable)
 	route.Run(":8085")
 }

binding/binding.go

@@ -6,8 +6,6 @@ package binding
 
 import (
 	"net/http"
-
-	validator "gopkg.in/go-playground/validator.v8"
 )
 
 const (
@@ -42,6 +40,10 @@ type StructValidator interface {
 	// If the struct is not valid or the validation itself fails, a descriptive error should be returned.
 	// Otherwise nil must be returned.
 	ValidateStruct(interface{}) error
+
+	// Engine returns the underlying validator engine which powers the
+	// StructValidator implementation.
+	Engine() interface{}
 }
 
 // Validator is the default validator which implements the StructValidator
@@ -89,18 +91,3 @@ func validate(obj interface{}) error {
 	}
 	return Validator.ValidateStruct(obj)
 }
-
-// ValidatorEngine returns the underlying validator engine which powers the
-// default Validator instance. This is useful if you want to register custom
-// validations or struct level validations. See validator GoDoc for more info -
-// https://godoc.org/gopkg.in/go-playground/validator.v8
-func ValidatorEngine() *validator.Validate {
-	if Validator == nil {
-		return nil
-	}
-	if v, ok := Validator.(*defaultValidator); ok {
-		v.lazyinit()
-		return v.validate
-	}
-	return nil
-}

binding/default_validator.go

@@ -28,6 +28,15 @@ func (v *defaultValidator) ValidateStruct(obj interface{}) error {
 	return nil
 }
 
+// Engine returns the underlying validator engine which powers the default
+// Validator instance. This is useful if you want to register custom validations
+// or struct level validations. See validator GoDoc for more info -
+// https://godoc.org/gopkg.in/go-playground/validator.v8
+func (v *defaultValidator) Engine() interface{} {
+	v.lazyinit()
+	return v.validate
+}
+
 func (v *defaultValidator) lazyinit() {
 	v.once.Do(func() {
 		config := &validator.Config{TagName: "binding"}

binding/validate_test.go

@@ -218,8 +218,8 @@ func TestValidatorEngine(t *testing.T) {
 	// This validates that the function `notOne` matches
 	// the expected function signature by `defaultValidator`
 	// and by extension the validator library.
-	engine := ValidatorEngine()
-	assert.NotNil(t, engine)
+	engine, ok := Validator.Engine().(*validator.Validate)
+	assert.True(t, ok)
 
 	err := engine.RegisterValidation("notone", notOne)
 	// Check that we can register custom validation without error

examples/custom-validation/server.go

@@ -30,11 +30,11 @@ func bookableDate(
 
 func main() {
 	route := gin.Default()
-	v := binding.ValidatorEngine()
-	if v == nil {
-		panic("validator engine is nil")
+
+	if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
+		v.RegisterValidation("bookabledate", bookableDate)
 	}
-	v.RegisterValidation("bookabledate", bookableDate)
+
 	route.GET("/bookable", getBookable)
 	route.Run(":8085")
 }

examples/struct-lvl-validations/server.go

@@ -42,11 +42,11 @@ func UserStructLevelValidation(v *validator.Validate, structLevel *validator.Str
 
 func main() {
 	route := gin.Default()
-	v := binding.ValidatorEngine()
-	if v == nil {
-		panic("validator engine is nil")
+
+	if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
+		v.RegisterStructValidation(UserStructLevelValidation, User{})
 	}
-	v.RegisterStructValidation(UserStructLevelValidation, User{})
+
 	route.POST("/user", validateUser)
 	route.Run(":8085")
 }