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16 KiB
16 KiB
Package validator
[](https://gitter.im/go-playground/validator?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
[](https://semaphoreci.com/joeybloggs/validator)
[](https://coveralls.io/github/go-playground/validator?branch=v9)
[](https://goreportcard.com/report/github.com/go-playground/validator)
[](https://godoc.org/gopkg.in/go-playground/validator.v9)
Package validator implements value validations for structs and individual fields based on tags.
It has the following unique features:
- Cross Field and Cross Struct validations by using validation tags or custom validators.
- Slice, Array and Map diving, which allows any or all levels of a multidimensional field to be validated.
- Handles type interface by determining it's underlying type prior to validation.
- Handles custom field types such as sql driver Valuer see Valuer
- Alias validation tags, which allows for mapping of several validations to a single tag for easier defining of validations on structs
- Extraction of custom defined Field Name e.g. can specify to extract the JSON name while validating and have it available in the resulting FieldError
Installation
Use go get.
go get gopkg.in/go-playground/validator.v9
or to update
go get -u gopkg.in/go-playground/validator.v9
Then import the validator package into your own code.
import "gopkg.in/go-playground/validator.v9"
Error Return Value
Validation functions return type error
They return type error to avoid the issue discussed in the following, where err is always != nil:
Validator only InvalidValidationError for bad validation input, nil or ValidationErrors as type error; so, in your code all you need to do is check if the error returned is not nil, and if it's not check if error is InvalidValidationError ( if necessary, most of the time it isn't ) type cast it to type ValidationErrors like so:
err := validate.Struct(mystruct)
validationErrors := err.(validator.ValidationErrors)
Usage and documentation
Please see http://godoc.org/gopkg.in/go-playground/validator.v9 for detailed usage docs.
Examples:
Struct & Field validation
package main
import (
"fmt"
"gopkg.in/go-playground/validator.v9"
)
// User contains user information
type User struct {
FirstName string `validate:"required"`
LastName string `validate:"required"`
Age uint8 `validate:"gte=0,lte=130"`
Email string `validate:"required,email"`
FavouriteColor string `validate:"iscolor"` // alias for 'hexcolor|rgb|rgba|hsl|hsla'
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"`
}
// use a single instance of Validate, it caches struct info
var validate *validator.Validate
func main() {
validate = validator.New()
validateStruct()
validateVariable()
}
func validateStruct() {
address := &Address{
Street: "Eavesdown Docks",
Planet: "Persphone",
Phone: "none",
}
user := &User{
FirstName: "Badger",
LastName: "Smith",
Age: 135,
Email: "Badger.Smith@gmail.com",
FavouriteColor: "#000-",
Addresses: []*Address{address},
}
// returns nil or ValidationErrors ( map[string]*FieldError )
err := validate.Struct(user)
if err != nil {
// this check is only needed when your code could produce
// an invalid value for validation such as interface with nil
// value most including myself do not usually have code like this.
if _, ok := err.(*validator.InvalidValidationError); ok {
fmt.Println(err)
return
}
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err.Namespace())
fmt.Println(err.Field())
fmt.Println(err.StructNamespace()) // can differ when a custom TagNameFunc is registered or
fmt.Println(err.StructField()) // by passing alt name to ReportError like below
fmt.Println(err.Tag())
fmt.Println(err.ActualTag())
fmt.Println(err.Kind())
fmt.Println(err.Type())
fmt.Println(err.Value())
fmt.Println(err.Param())
fmt.Println()
}
// from here you can create your own error messages in whatever language you wish
return
}
// save user to database
}
func validateVariable() {
myEmail := "joeybloggs.gmail.com"
errs := validate.Var(myEmail, "required,email")
if errs != nil {
fmt.Println(errs) // output: Key: "" Error:Field validation for "" failed on the "email" tag
return
}
// email ok, move on
}
Custom Field Type
package main
import (
"database/sql"
"database/sql/driver"
"fmt"
"reflect"
"gopkg.in/go-playground/validator.v9"
)
// DbBackedUser User struct
type DbBackedUser struct {
Name sql.NullString `validate:"required"`
Age sql.NullInt64 `validate:"required"`
}
// use a single instance of Validate, it caches struct info
var validate *validator.Validate
func main() {
validate = validator.New()
// register all sql.Null* types to use the ValidateValuer CustomTypeFunc
validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})
// build object for validation
x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}
err := validate.Struct(x)
if err != nil {
fmt.Printf("Err(s):\n%+v\n", err)
}
}
// 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
}
Struct Level Validation
package main
import (
"fmt"
"gopkg.in/go-playground/validator.v9"
)
// 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"`
}
// use a single instance of Validate, it caches struct info
var validate *validator.Validate
func main() {
validate = validator.New()
// register validation for 'User'
// NOTE: only have to register a non-pointer type for 'User', validator
// interanlly dereferences during it's type checks.
validate.RegisterStructValidation(UserStructLevelValidation, User{})
// build 'User' info, normally posted data etc...
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 InvalidValidationError for bad validation input, nil or ValidationErrors ( []FieldError )
err := validate.Struct(user)
if err != nil {
// this check is only needed when your code could produce
// an invalid value for validation such as interface with nil
// value most including myself do not usually have code like this.
if _, ok := err.(*validator.InvalidValidationError); ok {
fmt.Println(err)
return
}
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err.Namespace())
fmt.Println(err.Field())
fmt.Println(err.StructNamespace()) // can differ when a custom TagNameFunc is registered or
fmt.Println(err.StructField()) // by passing alt name to ReportError like below
fmt.Println(err.Tag())
fmt.Println(err.ActualTag())
fmt.Println(err.Kind())
fmt.Println(err.Type())
fmt.Println(err.Value())
fmt.Println(err.Param())
fmt.Println()
}
// from here you can create your own error messages in whatever language you wish
return
}
// save user to database
}
// 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(sl validator.StructLevel) {
user := sl.Current().Interface().(User)
if len(user.FirstName) == 0 && len(user.LastName) == 0 {
sl.ReportError(user.FirstName, "FirstName", "fname", "fnameorlname", "")
sl.ReportError(user.LastName, "LastName", "lname", "fnameorlname", "")
}
// plus can to more, even with different tag than "fnameorlname"
}
Benchmarks
Run on MacBook Pro (Retina, 15-inch, Late 2013) 2.6 GHz Intel Core i7 16 GB 1600 MHz DDR3 using Go version go1.6.3 darwin/amd64
BenchmarkFieldSuccess-8 10000000 147 ns/op 0 B/op 0 allocs/op
BenchmarkFieldSuccessParallel-8 30000000 42.5 ns/op 0 B/op 0 allocs/op
BenchmarkFieldFailure-8 3000000 417 ns/op 192 B/op 4 allocs/op
BenchmarkFieldFailureParallel-8 10000000 140 ns/op 192 B/op 4 allocs/op
BenchmarkFieldDiveSuccess-8 2000000 876 ns/op 201 B/op 11 allocs/op
BenchmarkFieldDiveSuccessParallel-8 5000000 277 ns/op 201 B/op 11 allocs/op
BenchmarkFieldDiveFailure-8 1000000 1185 ns/op 396 B/op 16 allocs/op
BenchmarkFieldDiveFailureParallel-8 3000000 402 ns/op 397 B/op 16 allocs/op
BenchmarkFieldCustomTypeSuccess-8 5000000 321 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeSuccessParallel-8 20000000 104 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeFailure-8 3000000 416 ns/op 192 B/op 4 allocs/op
BenchmarkFieldCustomTypeFailureParallel-8 10000000 150 ns/op 192 B/op 4 allocs/op
BenchmarkFieldOrTagSuccess-8 1000000 1119 ns/op 16 B/op 1 allocs/op
BenchmarkFieldOrTagSuccessParallel-8 3000000 462 ns/op 16 B/op 1 allocs/op
BenchmarkFieldOrTagFailure-8 2000000 715 ns/op 208 B/op 5 allocs/op
BenchmarkFieldOrTagFailureParallel-8 3000000 436 ns/op 208 B/op 5 allocs/op
BenchmarkStructLevelValidationSuccess-8 3000000 399 ns/op 32 B/op 2 allocs/op
BenchmarkStructLevelValidationSuccessParallel-8 20000000 140 ns/op 32 B/op 2 allocs/op
BenchmarkStructLevelValidationFailure-8 2000000 749 ns/op 288 B/op 8 allocs/op
BenchmarkStructLevelValidationFailureParallel-8 5000000 296 ns/op 288 B/op 8 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-8 2000000 673 ns/op 32 B/op 2 allocs/op
BenchmarkStructSimpleCustomTypeSuccessParallel-8 10000000 213 ns/op 32 B/op 2 allocs/op
BenchmarkStructSimpleCustomTypeFailure-8 1000000 1056 ns/op 392 B/op 9 allocs/op
BenchmarkStructSimpleCustomTypeFailureParallel-8 3000000 450 ns/op 408 B/op 10 allocs/op
BenchmarkStructPartialSuccess-8 2000000 789 ns/op 256 B/op 6 allocs/op
BenchmarkStructPartialSuccessParallel-8 5000000 307 ns/op 256 B/op 6 allocs/op
BenchmarkStructPartialFailure-8 1000000 1105 ns/op 464 B/op 11 allocs/op
BenchmarkStructPartialFailureParallel-8 5000000 493 ns/op 464 B/op 11 allocs/op
BenchmarkStructExceptSuccess-8 1000000 1212 ns/op 480 B/op 12 allocs/op
BenchmarkStructExceptSuccessParallel-8 10000000 282 ns/op 240 B/op 5 allocs/op
BenchmarkStructExceptFailure-8 1000000 1004 ns/op 448 B/op 10 allocs/op
BenchmarkStructExceptFailureParallel-8 5000000 452 ns/op 448 B/op 10 allocs/op
BenchmarkStructSimpleCrossFieldSuccess-8 2000000 656 ns/op 72 B/op 3 allocs/op
BenchmarkStructSimpleCrossFieldSuccessParallel-8 5000000 211 ns/op 72 B/op 3 allocs/op
BenchmarkStructSimpleCrossFieldFailure-8 2000000 968 ns/op 288 B/op 8 allocs/op
BenchmarkStructSimpleCrossFieldFailureParallel-8 5000000 406 ns/op 288 B/op 8 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-8 1000000 1000 ns/op 80 B/op 4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8 5000000 334 ns/op 80 B/op 4 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-8 1000000 1324 ns/op 304 B/op 9 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8 3000000 520 ns/op 304 B/op 9 allocs/op
BenchmarkStructSimpleSuccess-8 3000000 534 ns/op 0 B/op 0 allocs/op
BenchmarkStructSimpleSuccessParallel-8 10000000 144 ns/op 0 B/op 0 allocs/op
BenchmarkStructSimpleFailure-8 1000000 1039 ns/op 392 B/op 9 allocs/op
BenchmarkStructSimpleFailureParallel-8 5000000 419 ns/op 392 B/op 9 allocs/op
BenchmarkStructComplexSuccess-8 500000 2678 ns/op 128 B/op 8 allocs/op
BenchmarkStructComplexSuccessParallel-8 2000000 874 ns/op 128 B/op 8 allocs/op
BenchmarkStructComplexFailure-8 200000 6342 ns/op 2833 B/op 53 allocs/op
BenchmarkStructComplexFailureParallel-8 1000000 2875 ns/op 2833 B/op 53 allocs/op
Complimentary Software
Here is a list of software that compliments using this library either pre or post validation.
- form - Decodes url.Values into Go value(s) and Encodes Go value(s) into url.Values. Dual Array and Full map support.
- Conform - Trims, sanitizes & scrubs data based on struct tags.
How to Contribute
Make a pull request...
License
Distributed under MIT License, please see license file in code for more details.