Package validator ================ [![Join the chat at https://gitter.im/bluesuncorp/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) [![Build Status](https://semaphoreci.com/api/v1/projects/ec20115f-ef1b-4c7d-9393-cc76aba74eb4/523019/badge.svg)](https://semaphoreci.com/joeybloggs/validator) [![Coverage Status](https://coveralls.io/repos/go-playground/validator/badge.svg?branch=v8-development&service=github)](https://coveralls.io/github/go-playground/validator?branch=v8-development) [![Go Report Card](http://goreportcard.com/badge/go-playground/validator)](http://goreportcard.com/report/go-playground/validator) [![GoDoc](https://godoc.org/gopkg.in/go-playground/validator.v8?status.svg)](https://godoc.org/gopkg.in/go-playground/validator.v8) 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 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: * http://stackoverflow.com/a/29138676/3158232 * https://github.com/go-playground/validator/issues/134 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: ```go 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 ```go 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 ```go 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 ```go 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 $ 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.