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13 KiB
13 KiB
Package validator
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.v8
or to update
go get -u gopkg.in/go-playground/validator.v8
Then import the validator package into your own code.
import "gopkg.in/go-playground/validator.v8"
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 returns nil or ValidationErrors as type error; so in you code all you need to do is check if the error returned is not nil, and if it's not 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.v8 for detailed usage docs.
Examples:
Struct & Field validation
package main
import (
"fmt"
"gopkg.in/go-playground/validator.v8"
)
// 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:"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)
validateStruct()
validateField()
}
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 )
errs := validate.Struct(user)
if errs != nil {
fmt.Println(errs) // output: Key: "User.Age" Error:Field validation for "Age" failed on the "lte" tag
// Key: "User.Addresses[0].City" Error:Field validation for "City" failed on the "required" tag
err := errs.(validator.ValidationErrors)["User.Addresses[0].City"]
fmt.Println(err.Field) // output: City
fmt.Println(err.Tag) // output: required
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
}
func validateField() {
myEmail := "joeybloggs.gmail.com"
errs := validate.Field(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.v8"
)
// DbBackedUser User struct
type DbBackedUser struct {
Name sql.NullString `validate:"required"`
Age sql.NullInt64 `validate:"required"`
}
func main() {
config := &validator.Config{TagName: "validate"}
validate := validator.New(config)
// register all sql.Null* types to use the ValidateValuer CustomTypeFunc
validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})
x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}
errs := validate.Struct(x)
if len(errs.(validator.ValidationErrors)) > 0 {
fmt.Printf("Errs:\n%+v\n", errs)
}
}
// 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"
"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
}
Benchmarks
Run on MacBook Pro (Retina, 15-inch, Late 2013) 2.6 GHz Intel Core i7 16 GB 1600 MHz DDR3 using Go 1.5.1
$ go test -cpu=4 -bench=. -benchmem=true
PASS
BenchmarkFieldSuccess-4 5000000 288 ns/op 16 B/op 1 allocs/op
BenchmarkFieldFailure-4 5000000 292 ns/op 16 B/op 1 allocs/op
BenchmarkFieldDiveSuccess-4 500000 3464 ns/op 528 B/op 28 allocs/op
BenchmarkFieldDiveFailure-4 500000 4031 ns/op 928 B/op 32 allocs/op
BenchmarkFieldCustomTypeSuccess-4 3000000 446 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeFailure-4 2000000 755 ns/op 400 B/op 4 allocs/op
BenchmarkFieldOrTagSuccess-4 1000000 1356 ns/op 32 B/op 2 allocs/op
BenchmarkFieldOrTagFailure-4 1000000 1177 ns/op 432 B/op 6 allocs/op
BenchmarkStructLevelValidationSuccess-4 2000000 810 ns/op 160 B/op 6 allocs/op
BenchmarkStructLevelValidationFailure-4 1000000 1424 ns/op 592 B/op 11 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-4 1000000 1231 ns/op 80 B/op 5 allocs/op
BenchmarkStructSimpleCustomTypeFailure-4 1000000 1779 ns/op 624 B/op 11 allocs/op
BenchmarkStructPartialSuccess-4 1000000 1396 ns/op 400 B/op 11 allocs/op
BenchmarkStructPartialFailure-4 1000000 1928 ns/op 816 B/op 16 allocs/op
BenchmarkStructExceptSuccess-4 2000000 946 ns/op 368 B/op 9 allocs/op
BenchmarkStructExceptFailure-4 1000000 1396 ns/op 400 B/op 11 allocs/op
BenchmarkStructSimpleCrossFieldSuccess-4 1000000 1241 ns/op 128 B/op 6 allocs/op
BenchmarkStructSimpleCrossFieldFailure-4 1000000 1837 ns/op 560 B/op 11 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldSuccess-4 1000000 1867 ns/op 176 B/op 9 allocs/op
BenchmarkStructSimpleCrossStructCrossFieldFailure-4 500000 2495 ns/op 608 B/op 14 allocs/op
BenchmarkStructSimpleSuccess-4 1000000 1253 ns/op 48 B/op 3 allocs/op
BenchmarkStructSimpleFailure-4 1000000 1852 ns/op 624 B/op 11 allocs/op
BenchmarkStructSimpleSuccessParallel-4 5000000 372 ns/op 48 B/op 3 allocs/op
BenchmarkStructSimpleFailureParallel-4 2000000 784 ns/op 624 B/op 11 allocs/op
BenchmarkStructComplexSuccess-4 200000 8080 ns/op 512 B/op 30 allocs/op
BenchmarkStructComplexFailure-4 100000 12643 ns/op 3416 B/op 72 allocs/op
BenchmarkStructComplexSuccessParallel-4 1000000 2688 ns/op 512 B/op 30 allocs/op
BenchmarkStructComplexFailureParallel-4 300000 4727 ns/op 3416 B/op 72 allocs/op
How to Contribute
There will always be a development branch for each version i.e. v1-development. In order to contribute,
please make your pull requests against those branches.
If the changes being proposed or requested are breaking changes, please create an issue, for discussion or create a pull request against the highest development branch for example this package has a v1 and v1-development branch however, there will also be a v2-development branch even though v2 doesn't exist yet.
I strongly encourage everyone whom creates a custom validation function to contribute them and help make this package even better.
License
Distributed under MIT License, please see license file in code for more details.