package main
import (
"fmt"
"reflect"
"gopkg.in/go-playground/validator.v8"
)
// User contains user information
type User struct {
FirstName string `json:"fname"`
LastName string `json:"lname"`
Age uint8 `validate:"gte=0,lte=130"`
Email string `validate:"required,email"`
FavouriteColor string `validate:"hexcolor|rgb|rgba"`
Addresses []*Address `validate:"required,dive,required"` // a person can have a home and cottage...
}
// Address houses a users address information
type Address struct {
Street string `validate:"required"`
City string `validate:"required"`
Planet string `validate:"required"`
Phone string `validate:"required"`
}
var validate *validator.Validate
func main() {
config := &validator.Config{TagName: "validate"}
validate = validator.New(config)
validate.RegisterStructValidation(UserStructLevelValidation, User{})
validateStruct()
}
// UserStructLevelValidation contains custom struct level validations that don't always
// make sense at the field validation level. For Example this function validates that either
// FirstName or LastName exist; could have done that with a custom field validation but then
// would have had to add it to both fields duplicating the logic + overhead, this way it's
// only validated once.
//
// NOTE: you may ask why wouldn't I just do this outside of validator, because doing this way
// hooks right into validator and you can combine with validation tags and still have a
// common error output format.
func UserStructLevelValidation(v *validator.Validate, structLevel *validator.StructLevel) {
user := structLevel.CurrentStruct.Interface().(User)
if len(user.FirstName) == 0 && len(user.LastName) == 0 {
structLevel.ReportError(reflect.ValueOf(user.FirstName), "FirstName", "fname", "fnameorlname")
structLevel.ReportError(reflect.ValueOf(user.LastName), "LastName", "lname", "fnameorlname")
}
// plus can to more, even with different tag than "fnameorlname"
}
func validateStruct() {
address := &Address{
Street: "Eavesdown Docks",
Planet: "Persphone",
Phone: "none",
City: "Unknown",
}
user := &User{
FirstName: "",
LastName: "",
Age: 45,
Email: "Badger.Smith@gmail.com",
FavouriteColor: "#000",
Addresses: []*Address{address},
}
// returns nil or ValidationErrors ( map[string]*FieldError )
errs := validate.Struct(user)
if errs != nil {
fmt.Println(errs) // output: Key: 'User.LastName' Error:Field validation for 'LastName' failed on the 'fnameorlname' tag
// Key: 'User.FirstName' Error:Field validation for 'FirstName' failed on the 'fnameorlname' tag
err := errs.(validator.ValidationErrors)["User.FirstName"]
fmt.Println(err.Field) // output: FirstName
fmt.Println(err.Tag) // output: fnameorlname
fmt.Println(err.Kind) // output: string
fmt.Println(err.Type) // output: string
fmt.Println(err.Param) // output:
fmt.Println(err.Value) // output:
// from here you can create your own error messages in whatever language you wish
return
}
// save user to database
}$ go test -cpu=4 -bench=. -benchmem=true
PASS
BenchmarkFieldSuccess-4 5000000 305 ns/op 16 B/op 1 allocs/op
BenchmarkFieldFailure-4 5000000 301 ns/op 16 B/op 1 allocs/op
BenchmarkFieldDiveSuccess-4 500000 3544 ns/op 528 B/op 28 allocs/op
BenchmarkFieldDiveFailure-4 300000 4120 ns/op 928 B/op 32 allocs/op
BenchmarkFieldCustomTypeSuccess-4 3000000 465 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeFailure-4 2000000 769 ns/op 400 B/op 4 allocs/op
BenchmarkFieldOrTagSuccess-4 1000000 1372 ns/op 32 B/op 2 allocs/op
BenchmarkFieldOrTagFailure-4 1000000 1218 ns/op 432 B/op 6 allocs/op
BenchmarkStructLevelValidationSuccess-4 2000000 840 ns/op 160 B/op 6 allocs/op
BenchmarkStructLevelValidationFailure-4 1000000 1443 ns/op 592 B/op 11 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-4 1000000 1262 ns/op 80 B/op 5 allocs/op
BenchmarkStructSimpleCustomTypeFailure-4 1000000 1812 ns/op 624 B/op 11 allocs/op
BenchmarkStructPartialSuccess-4 1000000 1419 ns/op 400 B/op 11 allocs/op
BenchmarkStructPartialFailure-4 1000000 1967 ns/op 816 B/op 16 allocs/op
BenchmarkStructExceptSuccess-4 2000000 954 ns/op 368 B/op 9 allocs/op
BenchmarkStructExceptFailure-4 1000000 1422 ns/op 400 B/op 11 allocs/op
BenchmarkStructSimpleCrossFieldSuccess-4 1000000 1286 ns/op 128 B/op 6 allocs/op
BenchmarkStructSimpleCrossFieldFailure-4 1000000 1885 ns/op 560 B/op 11 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-4 1000000 1948 ns/op 176 B/op 9 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-4 500000 2491 ns/op 608 B/op 14 allocs/op
BenchmarkStructSimpleSuccess-4 1000000 1239 ns/op 48 B/op 3 allocs/op
BenchmarkStructSimpleFailure-4 1000000 1891 ns/op 624 B/op 11 allocs/op
BenchmarkStructSimpleSuccessParallel-4 5000000 386 ns/op 48 B/op 3 allocs/op
BenchmarkStructSimpleFailureParallel-4 2000000 842 ns/op 624 B/op 11 allocs/op
BenchmarkStructComplexSuccess-4 200000 8604 ns/op 512 B/op 30 allocs/op
BenchmarkStructComplexFailure-4 100000 13332 ns/op 3416 B/op 72 allocs/op
BenchmarkStructComplexSuccessParallel-4 1000000 2929 ns/op 512 B/op 30 allocs/op
BenchmarkStructComplexFailureParallel-4 300000 5220 ns/op 3416 B/op 72 allocs/op
