Package validator ================ [![Join the chat at https://gitter.im/go-playground/validator](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/go-playground/validator?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) ![Project status](https://img.shields.io/badge/version-9.1.0-green.svg) [![Build Status](https://semaphoreci.com/api/v1/joeybloggs/validator/branches/v9/badge.svg)](https://semaphoreci.com/joeybloggs/validator) [![Coverage Status](https://coveralls.io/repos/go-playground/validator/badge.svg?branch=v9&service=github)](https://coveralls.io/github/go-playground/validator?branch=v9) [![Go Report Card](https://goreportcard.com/badge/github.com/go-playground/validator)](https://goreportcard.com/report/github.com/go-playground/validator) [![GoDoc](https://godoc.org/gopkg.in/go-playground/validator.v9?status.svg)](https://godoc.org/gopkg.in/go-playground/validator.v9) ![License](https://img.shields.io/dub/l/vibe-d.svg) 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](https://golang.org/src/database/sql/driver/types.go?s=1210:1293#L29) - 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 - Default validator for the [gin](https://github.com/gin-gonic/gin) web framework; upgrading from v8 to v9 in gin see [here](https://github.com/go-playground/validator/tree/v9/examples/gin-upgrading-overriding) Installation ------------ Use go get. go get 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: * http://stackoverflow.com/a/29138676/3158232 * https://github.com/go-playground/validator/issues/134 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: ```go 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 ```go 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 ```go 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 ```go 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 go1.7 darwin/amd64 ```go BenchmarkFieldSuccess-8 20000000 105 ns/op 0 B/op 0 allocs/op BenchmarkFieldSuccessParallel-8 50000000 35.1 ns/op 0 B/op 0 allocs/op BenchmarkFieldFailure-8 5000000 337 ns/op 208 B/op 4 allocs/op BenchmarkFieldFailureParallel-8 20000000 120 ns/op 208 B/op 4 allocs/op BenchmarkFieldDiveSuccess-8 2000000 716 ns/op 201 B/op 11 allocs/op BenchmarkFieldDiveSuccessParallel-8 10000000 253 ns/op 201 B/op 11 allocs/op BenchmarkFieldDiveFailure-8 1000000 1060 ns/op 412 B/op 16 allocs/op BenchmarkFieldDiveFailureParallel-8 5000000 360 ns/op 413 B/op 16 allocs/op BenchmarkFieldCustomTypeSuccess-8 5000000 299 ns/op 32 B/op 2 allocs/op BenchmarkFieldCustomTypeSuccessParallel-8 20000000 86.0 ns/op 32 B/op 2 allocs/op BenchmarkFieldCustomTypeFailure-8 5000000 341 ns/op 208 B/op 4 allocs/op BenchmarkFieldCustomTypeFailureParallel-8 20000000 140 ns/op 208 B/op 4 allocs/op BenchmarkFieldOrTagSuccess-8 2000000 893 ns/op 16 B/op 1 allocs/op BenchmarkFieldOrTagSuccessParallel-8 5000000 431 ns/op 16 B/op 1 allocs/op BenchmarkFieldOrTagFailure-8 2000000 563 ns/op 224 B/op 5 allocs/op BenchmarkFieldOrTagFailureParallel-8 5000000 417 ns/op 224 B/op 5 allocs/op BenchmarkStructLevelValidationSuccess-8 5000000 339 ns/op 32 B/op 2 allocs/op BenchmarkStructLevelValidationSuccessParallel-8 20000000 114 ns/op 32 B/op 2 allocs/op BenchmarkStructLevelValidationFailure-8 2000000 630 ns/op 304 B/op 8 allocs/op BenchmarkStructLevelValidationFailureParallel-8 5000000 291 ns/op 304 B/op 8 allocs/op BenchmarkStructSimpleCustomTypeSuccess-8 3000000 540 ns/op 32 B/op 2 allocs/op BenchmarkStructSimpleCustomTypeSuccessParallel-8 10000000 176 ns/op 32 B/op 2 allocs/op BenchmarkStructSimpleCustomTypeFailure-8 2000000 821 ns/op 424 B/op 9 allocs/op BenchmarkStructSimpleCustomTypeFailureParallel-8 5000000 336 ns/op 440 B/op 10 allocs/op BenchmarkStructPartialSuccess-8 2000000 686 ns/op 256 B/op 6 allocs/op BenchmarkStructPartialSuccessParallel-8 5000000 282 ns/op 256 B/op 6 allocs/op BenchmarkStructPartialFailure-8 2000000 931 ns/op 480 B/op 11 allocs/op BenchmarkStructPartialFailureParallel-8 5000000 394 ns/op 480 B/op 11 allocs/op BenchmarkStructExceptSuccess-8 1000000 1017 ns/op 496 B/op 12 allocs/op BenchmarkStructExceptSuccessParallel-8 10000000 233 ns/op 240 B/op 5 allocs/op BenchmarkStructExceptFailure-8 2000000 864 ns/op 464 B/op 10 allocs/op BenchmarkStructExceptFailureParallel-8 5000000 393 ns/op 464 B/op 10 allocs/op BenchmarkStructSimpleCrossFieldSuccess-8 3000000 552 ns/op 72 B/op 3 allocs/op BenchmarkStructSimpleCrossFieldSuccessParallel-8 10000000 202 ns/op 72 B/op 3 allocs/op BenchmarkStructSimpleCrossFieldFailure-8 2000000 798 ns/op 304 B/op 8 allocs/op BenchmarkStructSimpleCrossFieldFailureParallel-8 5000000 356 ns/op 304 B/op 8 allocs/op BenchmarkStructSimpleCrossStructCrossFieldSuccess-8 2000000 825 ns/op 80 B/op 4 allocs/op BenchmarkStructSimpleCrossStructCrossFieldSuccessParallel-8 5000000 300 ns/op 80 B/op 4 allocs/op BenchmarkStructSimpleCrossStructCrossFieldFailure-8 2000000 1103 ns/op 320 B/op 9 allocs/op BenchmarkStructSimpleCrossStructCrossFieldFailureParallel-8 3000000 433 ns/op 320 B/op 9 allocs/op BenchmarkStructSimpleSuccess-8 5000000 360 ns/op 0 B/op 0 allocs/op BenchmarkStructSimpleSuccessParallel-8 20000000 110 ns/op 0 B/op 0 allocs/op BenchmarkStructSimpleFailure-8 2000000 783 ns/op 424 B/op 9 allocs/op BenchmarkStructSimpleFailureParallel-8 5000000 358 ns/op 424 B/op 9 allocs/op BenchmarkStructComplexSuccess-8 1000000 2120 ns/op 128 B/op 8 allocs/op BenchmarkStructComplexSuccessParallel-8 2000000 659 ns/op 128 B/op 8 allocs/op BenchmarkStructComplexFailure-8 300000 5126 ns/op 3041 B/op 53 allocs/op BenchmarkStructComplexFailureParallel-8 1000000 2261 ns/op 3041 B/op 53 allocs/op ``` Complimentary Software ---------------------- Here is a list of software that compliments using this library either pre or post validation. * [form](https://github.com/go-playground/form) - Decodes url.Values into Go value(s) and Encodes Go value(s) into url.Values. Dual Array and Full map support. * [Conform](https://github.com/leebenson/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.