Add RegisterCustomTypeFunc for easier adding of CustomTypeFunc

Thanks @johnniedoe for ths pull request!

README.md

@@ -2,7 +2,7 @@ Package validator
 ================
 
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+[![Build Status](https://semaphoreci.com/api/v1/projects/ec20115f-ef1b-4c7d-9393-cc76aba74eb4/487383/badge.svg)](https://semaphoreci.com/joeybloggs/validator)
 [![Coverage Status](https://coveralls.io/repos/bluesuncorp/validator/badge.svg?branch=v6)](https://coveralls.io/r/bluesuncorp/validator?branch=v6)
 [![GoDoc](https://godoc.org/gopkg.in/bluesuncorp/validator.v6?status.svg)](https://godoc.org/gopkg.in/bluesuncorp/validator.v6)
 
@@ -138,84 +138,51 @@ Custom Field Type
 package main
 
 import (
-	"errors"
+	"database/sql"
+	"database/sql/driver"
 	"fmt"
 	"reflect"
 
-	sql "database/sql/driver"
-
 	"gopkg.in/bluesuncorp/validator.v6"
 )
 
-var validate *validator.Validate
-
-type valuer struct {
-	Name string
-}
-
-func (v valuer) Value() (sql.Value, error) {
-
-	if v.Name == "errorme" {
-		return nil, errors.New("some kind of error")
-	}
-
-	if v.Name == "blankme" {
-		return "", nil
-	}
-
-	if len(v.Name) == 0 {
-		return nil, nil
-	}
-
-	return v.Name, nil
-}
-
-// ValidateValuerType implements validator.CustomTypeFunc
-func ValidateValuerType(field reflect.Value) interface{} {
-	if valuer, ok := field.Interface().(sql.Valuer); ok {
-		val, err := valuer.Value()
-		if err != nil {
-			// handle the error how you want
-			return nil
-		}
-
-		return val
-	}
-
-	return nil
+// DbBackedUser User struct
+type DbBackedUser struct {
+	Name sql.NullString `validate:"required"`
+	Age  sql.NullInt64  `validate:"required"`
 }
 
 func main() {
 
-	customTypes := map[reflect.Type]validator.CustomTypeFunc{}
-	customTypes[reflect.TypeOf((*sql.Valuer)(nil))] = ValidateValuerType
-	customTypes[reflect.TypeOf(valuer{})] = ValidateValuerType
-
 	config := validator.Config{
 		TagName:         "validate",
 		ValidationFuncs: validator.BakedInValidators,
-		CustomTypeFuncs: customTypes,
 	}
 
-	validate = validator.New(config)
+	validate := validator.New(config)
 
-	validateCustomFieldType()
-}
+	// register all sql.Null* types to use the ValidateValuer CustomTypeFunc
+	validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})
 
-func validateCustomFieldType() {
-	val := valuer{
-		Name: "blankme",
-	}
+	x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}
+	errs := validate.Struct(x)
 
-	errs := validate.Field(val, "required")
-	if errs != nil {
-		fmt.Println(errs) // output: Key: "" Error:Field validation for "" failed on the "required" tag
-		return
+	if len(errs) > 0 {
+		fmt.Printf("Errs:\n%+v\n", errs)
 	}
-
-	// all ok
 }
 
+// ValidateValuer implements validator.CustomTypeFunc
+func ValidateValuer(field reflect.Value) interface{} {
+	if valuer, ok := field.Interface().(driver.Valuer); ok {
+		val, err := valuer.Value()
+		if err == nil {
+			return val
+		}
+		// handle the error how you want
+	}
+	return nil
+}
 ```
 
 Benchmarks

examples/custom/custom.go

@@ -6,9 +6,10 @@ import (
 	"fmt"
 	"reflect"
 
-	validator "gopkg.in/bluesuncorp/validator.v6"
+	"gopkg.in/bluesuncorp/validator.v6"
 )
 
+// DbBackedUser User struct
 type DbBackedUser struct {
 	Name sql.NullString `validate:"required"`
 	Age  sql.NullInt64  `validate:"required"`

validator.go

@@ -157,14 +157,17 @@ func (v *Validate) RegisterValidation(key string, f Func) error {
 	return nil
 }
 
-// RegisterCustomTypeFunc registers types w/a custom type handler function.
-func (v *Validate) RegisterCustomTypeFunc(f CustomTypeFunc, sampleTypeValues ...interface{}) {
+// RegisterCustomTypeFunc registers a CustomTypeFunc against a number of types
+func (v *Validate) RegisterCustomTypeFunc(fn CustomTypeFunc, types ...interface{}) {
+
 	if v.config.CustomTypeFuncs == nil {
 		v.config.CustomTypeFuncs = map[reflect.Type]CustomTypeFunc{}
 	}
-	for _, sample := range sampleTypeValues {
-		v.config.CustomTypeFuncs[reflect.TypeOf(sample)] = f
+
+	for _, t := range types {
+		v.config.CustomTypeFuncs[reflect.TypeOf(t)] = fn
 	}
+
 	v.config.hasCustomFuncs = true
 }
 

validator_test.go

@@ -1,14 +1,14 @@
 package validator
 
 import (
+	"database/sql"
+	"database/sql/driver"
 	"errors"
 	"fmt"
 	"reflect"
 	"testing"
 	"time"
 
-	sql "database/sql/driver"
-
 	. "gopkg.in/bluesuncorp/assert.v1"
 )
 
@@ -126,7 +126,7 @@ type valuer struct {
 	Name string
 }
 
-func (v valuer) Value() (sql.Value, error) {
+func (v valuer) Value() (driver.Value, error) {
 
 	if v.Name == "errorme" {
 		return nil, errors.New("some kind of error")
@@ -178,7 +178,7 @@ type CustomMadeUpStruct struct {
 }
 
 func ValidateValuerType(field reflect.Value) interface{} {
-	if valuer, ok := field.Interface().(sql.Valuer); ok {
+	if valuer, ok := field.Interface().(driver.Valuer); ok {
 		val, err := valuer.Value()
 		if err != nil {
 			// handle the error how you want
@@ -191,10 +191,68 @@ func ValidateValuerType(field reflect.Value) interface{} {
 	return nil
 }
 
+func TestSQLValue2Validation(t *testing.T) {
+
+	config := Config{
+		TagName:         "validate",
+		ValidationFuncs: BakedInValidators,
+	}
+
+	validate := New(config)
+	validate.RegisterCustomTypeFunc(ValidateValuerType, valuer{}, (*driver.Valuer)(nil), sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})
+	validate.RegisterCustomTypeFunc(ValidateCustomType, MadeUpCustomType{})
+	validate.RegisterCustomTypeFunc(OverrideIntTypeForSomeReason, 1)
+
+	val := valuer{
+		Name: "",
+	}
+
+	errs := validate.Field(val, "required")
+	NotEqual(t, errs, nil)
+	AssertError(t, errs, "", "", "required")
+
+	val.Name = "Valid Name"
+	errs = validate.Field(val, "required")
+	Equal(t, errs, nil)
+
+	val.Name = "errorme"
+
+	PanicMatches(t, func() { errs = validate.Field(val, "required") }, "SQL Driver Valuer error: some kind of error")
+
+	type myValuer valuer
+
+	myVal := valuer{
+		Name: "",
+	}
+
+	errs = validate.Field(myVal, "required")
+	NotEqual(t, errs, nil)
+	AssertError(t, errs, "", "", "required")
+
+	cust := MadeUpCustomType{
+		FirstName: "Joey",
+		LastName:  "Bloggs",
+	}
+
+	c := CustomMadeUpStruct{MadeUp: cust, OverriddenInt: 2}
+
+	errs = validate.Struct(c)
+	Equal(t, errs, nil)
+
+	c.MadeUp.FirstName = ""
+	c.OverriddenInt = 1
+
+	errs = validate.Struct(c)
+	NotEqual(t, errs, nil)
+	Equal(t, len(errs), 2)
+	AssertError(t, errs, "CustomMadeUpStruct.MadeUp", "MadeUp", "required")
+	AssertError(t, errs, "CustomMadeUpStruct.OverriddenInt", "OverriddenInt", "gt")
+}
+
 func TestSQLValueValidation(t *testing.T) {
 
 	customTypes := map[reflect.Type]CustomTypeFunc{}
-	customTypes[reflect.TypeOf((*sql.Valuer)(nil))] = ValidateValuerType
+	customTypes[reflect.TypeOf((*driver.Valuer)(nil))] = ValidateValuerType
 	customTypes[reflect.TypeOf(valuer{})] = ValidateValuerType
 	customTypes[reflect.TypeOf(MadeUpCustomType{})] = ValidateCustomType
 	customTypes[reflect.TypeOf(1)] = OverrideIntTypeForSomeReason