368 lines
14 KiB
Markdown
368 lines
14 KiB
Markdown
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Package validator
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================
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<img align="right" src="https://raw.githubusercontent.com/go-playground/validator/v8/logo.png">
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[](https://gitter.im/go-playground/validator?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
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[](https://semaphoreci.com/joeybloggs/validator)
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[](https://coveralls.io/github/go-playground/validator?branch=v8)
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[](https://goreportcard.com/report/github.com/go-playground/validator)
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[](https://godoc.org/gopkg.in/go-playground/validator.v8)
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Package validator implements value validations for structs and individual fields based on tags.
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It has the following **unique** features:
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- Cross Field and Cross Struct validations by using validation tags or custom validators.
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- Slice, Array and Map diving, which allows any or all levels of a multidimensional field to be validated.
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- Handles type interface by determining it's underlying type prior to validation.
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- Handles custom field types such as sql driver Valuer see [Valuer](https://golang.org/src/database/sql/driver/types.go?s=1210:1293#L29)
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- Alias validation tags, which allows for mapping of several validations to a single tag for easier defining of validations on structs
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- 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
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Installation
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------------
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Use go get.
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go get gopkg.in/go-playground/validator.v8
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or to update
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go get -u gopkg.in/go-playground/validator.v8
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Then import the validator package into your own code.
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import "gopkg.in/go-playground/validator.v8"
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Error Return Value
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-------
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Validation functions return type error
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They return type error to avoid the issue discussed in the following, where err is always != nil:
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* http://stackoverflow.com/a/29138676/3158232
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* https://github.com/go-playground/validator/issues/134
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validator only returns nil or ValidationErrors as type error; so in you code all you need to do
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is check if the error returned is not nil, and if it's not type cast it to type ValidationErrors
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like so:
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```go
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err := validate.Struct(mystruct)
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validationErrors := err.(validator.ValidationErrors)
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```
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Usage and documentation
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------
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Please see http://godoc.org/gopkg.in/go-playground/validator.v8 for detailed usage docs.
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##### Examples:
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Struct & Field validation
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```go
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package main
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import (
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"fmt"
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"gopkg.in/go-playground/validator.v8"
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)
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// User contains user information
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type User struct {
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FirstName string `validate:"required"`
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LastName string `validate:"required"`
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Age uint8 `validate:"gte=0,lte=130"`
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Email string `validate:"required,email"`
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FavouriteColor string `validate:"hexcolor|rgb|rgba"`
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Addresses []*Address `validate:"required,dive,required"` // a person can have a home and cottage...
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}
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// Address houses a users address information
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type Address struct {
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Street string `validate:"required"`
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City string `validate:"required"`
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Planet string `validate:"required"`
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Phone string `validate:"required"`
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}
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var validate *validator.Validate
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func main() {
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config := &validator.Config{TagName: "validate"}
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validate = validator.New(config)
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validateStruct()
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validateField()
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}
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func validateStruct() {
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address := &Address{
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Street: "Eavesdown Docks",
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Planet: "Persphone",
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Phone: "none",
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}
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user := &User{
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FirstName: "Badger",
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LastName: "Smith",
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Age: 135,
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Email: "Badger.Smith@gmail.com",
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FavouriteColor: "#000",
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Addresses: []*Address{address},
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}
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// returns nil or ValidationErrors ( map[string]*FieldError )
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errs := validate.Struct(user)
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if errs != nil {
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fmt.Println(errs) // output: Key: "User.Age" Error:Field validation for "Age" failed on the "lte" tag
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// Key: "User.Addresses[0].City" Error:Field validation for "City" failed on the "required" tag
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err := errs.(validator.ValidationErrors)["User.Addresses[0].City"]
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fmt.Println(err.Field) // output: City
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fmt.Println(err.Tag) // output: required
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fmt.Println(err.Kind) // output: string
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fmt.Println(err.Type) // output: string
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fmt.Println(err.Param) // output:
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fmt.Println(err.Value) // output:
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// from here you can create your own error messages in whatever language you wish
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return
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}
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// save user to database
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}
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func validateField() {
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myEmail := "joeybloggs.gmail.com"
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errs := validate.Field(myEmail, "required,email")
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if errs != nil {
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fmt.Println(errs) // output: Key: "" Error:Field validation for "" failed on the "email" tag
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return
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}
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// email ok, move on
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}
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```
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Custom Field Type
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```go
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package main
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import (
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"database/sql"
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"database/sql/driver"
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"fmt"
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"reflect"
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"gopkg.in/go-playground/validator.v8"
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)
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// DbBackedUser User struct
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type DbBackedUser struct {
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Name sql.NullString `validate:"required"`
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Age sql.NullInt64 `validate:"required"`
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}
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func main() {
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config := &validator.Config{TagName: "validate"}
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validate := validator.New(config)
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// register all sql.Null* types to use the ValidateValuer CustomTypeFunc
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validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})
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x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}
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errs := validate.Struct(x)
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if len(errs.(validator.ValidationErrors)) > 0 {
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fmt.Printf("Errs:\n%+v\n", errs)
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}
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}
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// ValidateValuer implements validator.CustomTypeFunc
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func ValidateValuer(field reflect.Value) interface{} {
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if valuer, ok := field.Interface().(driver.Valuer); ok {
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val, err := valuer.Value()
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if err == nil {
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return val
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}
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// handle the error how you want
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}
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return nil
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}
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```
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Struct Level Validation
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```go
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package main
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import (
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"fmt"
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"reflect"
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"gopkg.in/go-playground/validator.v8"
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)
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// User contains user information
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type User struct {
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FirstName string `json:"fname"`
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LastName string `json:"lname"`
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Age uint8 `validate:"gte=0,lte=130"`
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Email string `validate:"required,email"`
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FavouriteColor string `validate:"hexcolor|rgb|rgba"`
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Addresses []*Address `validate:"required,dive,required"` // a person can have a home and cottage...
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}
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// Address houses a users address information
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type Address struct {
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Street string `validate:"required"`
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City string `validate:"required"`
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Planet string `validate:"required"`
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Phone string `validate:"required"`
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}
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var validate *validator.Validate
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func main() {
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config := &validator.Config{TagName: "validate"}
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validate = validator.New(config)
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validate.RegisterStructValidation(UserStructLevelValidation, User{})
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validateStruct()
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}
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// UserStructLevelValidation contains custom struct level validations that don't always
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// make sense at the field validation level. For Example this function validates that either
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// FirstName or LastName exist; could have done that with a custom field validation but then
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// would have had to add it to both fields duplicating the logic + overhead, this way it's
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// only validated once.
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//
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// NOTE: you may ask why wouldn't I just do this outside of validator, because doing this way
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// hooks right into validator and you can combine with validation tags and still have a
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// common error output format.
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func UserStructLevelValidation(v *validator.Validate, structLevel *validator.StructLevel) {
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user := structLevel.CurrentStruct.Interface().(User)
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if len(user.FirstName) == 0 && len(user.LastName) == 0 {
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structLevel.ReportError(reflect.ValueOf(user.FirstName), "FirstName", "fname", "fnameorlname")
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structLevel.ReportError(reflect.ValueOf(user.LastName), "LastName", "lname", "fnameorlname")
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}
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// plus can to more, even with different tag than "fnameorlname"
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}
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func validateStruct() {
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address := &Address{
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Street: "Eavesdown Docks",
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Planet: "Persphone",
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Phone: "none",
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City: "Unknown",
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}
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user := &User{
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FirstName: "",
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LastName: "",
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Age: 45,
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Email: "Badger.Smith@gmail.com",
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FavouriteColor: "#000",
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Addresses: []*Address{address},
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}
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// returns nil or ValidationErrors ( map[string]*FieldError )
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errs := validate.Struct(user)
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if errs != nil {
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fmt.Println(errs) // output: Key: 'User.LastName' Error:Field validation for 'LastName' failed on the 'fnameorlname' tag
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// Key: 'User.FirstName' Error:Field validation for 'FirstName' failed on the 'fnameorlname' tag
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err := errs.(validator.ValidationErrors)["User.FirstName"]
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fmt.Println(err.Field) // output: FirstName
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fmt.Println(err.Tag) // output: fnameorlname
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fmt.Println(err.Kind) // output: string
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fmt.Println(err.Type) // output: string
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fmt.Println(err.Param) // output:
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fmt.Println(err.Value) // output:
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// from here you can create your own error messages in whatever language you wish
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return
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}
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// save user to database
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}
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```
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Benchmarks
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------
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###### Run on MacBook Pro (Retina, 15-inch, Late 2013) 2.6 GHz Intel Core i7 16 GB 1600 MHz DDR3 using Go version go1.5.3 darwin/amd64
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```go
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PASS
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BenchmarkFieldSuccess-8 20000000 118 ns/op 0 B/op 0 allocs/op
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BenchmarkFieldFailure-8 2000000 758 ns/op 432 B/op 4 allocs/op
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BenchmarkFieldDiveSuccess-8 500000 2471 ns/op 464 B/op 28 allocs/op
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BenchmarkFieldDiveFailure-8 500000 3172 ns/op 896 B/op 32 allocs/op
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BenchmarkFieldCustomTypeSuccess-8 5000000 300 ns/op 32 B/op 2 allocs/op
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BenchmarkFieldCustomTypeFailure-8 2000000 775 ns/op 432 B/op 4 allocs/op
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BenchmarkFieldOrTagSuccess-8 1000000 1122 ns/op 4 B/op 1 allocs/op
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BenchmarkFieldOrTagFailure-8 1000000 1167 ns/op 448 B/op 6 allocs/op
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BenchmarkStructLevelValidationSuccess-8 3000000 548 ns/op 160 B/op 5 allocs/op
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BenchmarkStructLevelValidationFailure-8 3000000 558 ns/op 160 B/op 5 allocs/op
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BenchmarkStructSimpleCustomTypeSuccess-8 2000000 623 ns/op 36 B/op 3 allocs/op
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BenchmarkStructSimpleCustomTypeFailure-8 1000000 1381 ns/op 640 B/op 9 allocs/op
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BenchmarkStructPartialSuccess-8 1000000 1036 ns/op 272 B/op 9 allocs/op
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BenchmarkStructPartialFailure-8 1000000 1734 ns/op 730 B/op 14 allocs/op
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BenchmarkStructExceptSuccess-8 2000000 888 ns/op 250 B/op 7 allocs/op
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BenchmarkStructExceptFailure-8 1000000 1036 ns/op 272 B/op 9 allocs/op
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BenchmarkStructSimpleCrossFieldSuccess-8 2000000 773 ns/op 80 B/op 4 allocs/op
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BenchmarkStructSimpleCrossFieldFailure-8 1000000 1487 ns/op 536 B/op 9 allocs/op
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BenchmarkStructSimpleCrossStructCrossFieldSuccess-8 1000000 1261 ns/op 112 B/op 7 allocs/op
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BenchmarkStructSimpleCrossStructCrossFieldFailure-8 1000000 2055 ns/op 576 B/op 12 allocs/op
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BenchmarkStructSimpleSuccess-8 3000000 519 ns/op 4 B/op 1 allocs/op
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BenchmarkStructSimpleFailure-8 1000000 1429 ns/op 640 B/op 9 allocs/op
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BenchmarkStructSimpleSuccessParallel-8 10000000 146 ns/op 4 B/op 1 allocs/op
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BenchmarkStructSimpleFailureParallel-8 2000000 551 ns/op 640 B/op 9 allocs/op
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BenchmarkStructComplexSuccess-8 500000 3269 ns/op 244 B/op 15 allocs/op
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BenchmarkStructComplexFailure-8 200000 8436 ns/op 3609 B/op 60 allocs/op
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BenchmarkStructComplexSuccessParallel-8 1000000 1024 ns/op 244 B/op 15 allocs/op
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BenchmarkStructComplexFailureParallel-8 500000 3536 ns/op 3609 B/op 60 allocs/op
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```
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Complimentary Software
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----------------------
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Here is a list of software that compliments using this library either pre or post validation.
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* [Gorilla Schema](https://github.com/gorilla/schema) - Package gorilla/schema fills a struct with form values.
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* [Conform](https://github.com/leebenson/conform) - Trims, sanitizes & scrubs data based on struct tags.
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How to Contribute
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------
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There will always be a development branch for each version i.e. `v1-development`. In order to contribute,
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please make your pull requests against those branches.
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If the changes being proposed or requested are breaking changes, please create an issue, for discussion
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or create a pull request against the highest development branch for example this package has a
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v1 and v1-development branch however, there will also be a v2-development branch even though v2 doesn't exist yet.
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I strongly encourage everyone whom creates a custom validation function to contribute them and
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help make this package even better.
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License
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Distributed under MIT License, please see license file in code for more details.
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