Model Validation

Iris does not contain built-in method for validating request data such as "Models". However, you are not limited. In this example we will learn how to use the go-playground/validator.v9 for request values validation.

Check the full docs on tags usage here.

$ go get gopkg.in/go-playground/validator.v9

Note that you need to set the corresponding binding tag on all fields you want to bind. For example, when binding from JSON, set json:"fieldname".

package main
import (
"fmt"
"github.com/kataras/iris/v12"
"gopkg.in/go-playground/validator.v9"
)
// User contains user information.
type User struct {
FirstName string `json:"fname"`
LastName string `json:"lname"`
Age uint8 `json:"age" validate:"gte=0,lte=130"`
Email string `json:"email" validate:"required,email"`
FavouriteColor string `json:"favColor" validate:"hexcolor|rgb|rgba"`
Addresses []*Address `json:"addresses" validate:"required,dive,required"`
}
// Address houses a users address information.
type Address struct {
Street string `json:"street" validate:"required"`
City string `json:"city" validate:"required"`
Planet string `json:"planet" validate:"required"`
Phone string `json:"phone" 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
// internally dereferences during it's type checks.
validate.RegisterStructValidation(UserStructLevelValidation, User{})
app := iris.New()
app.Post("/user", func(ctx iris.Context) {
var user User
if err := ctx.ReadJSON(&user); err != nil {
// [handle error...]
}
// 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 {
ctx.StatusCode(iris.StatusInternalServerError)
ctx.WriteString(err.Error())
return
}
ctx.StatusCode(iris.StatusBadRequest)
for _, err := range err.(validator.ValidationErrors) {
fmt.Println()
fmt.Println(err.Namespace())
fmt.Println(err.Field())
fmt.Println(err.StructNamespace())
fmt.Println(err.StructField())
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()
}
return
}
// [save user to database...]
})
app.Run(iris.Addr(":8080"))
}
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", "")
}
}

Example request of JSON form:

{
"fname": "",
"lname": "",
"age": 45,
"email": "mail@example.com",
"favColor": "#000",
"addresses": [{
"street": "Eavesdown Docks",
"planet": "Persphone",
"phone": "none",
"city": "Unknown"
}]
}

Example can be found at: https://github.com/kataras/iris/tree/master/_examples/http_request/read-json-struct-validation/main.go.