SIMPLE_STRUCT_VALIDATION.md

Validate JSON body into a simple Struct

When using ValidateJSON you must provide data struct or map, rules and request. You can also pass message rules if you need custom message or localization.

package main

import (
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/thedevsaddam/govalidator"
)

type user struct {
	Username string           `json:"username"`
	Email    string           `json:"email"`
	Web      string           `json:"web"`
	Age      govalidator.Int  `json:"age"`
	Agree    govalidator.Bool `json:"agree"`
}

func handler(w http.ResponseWriter, r *http.Request) {
	var user user
	rules := govalidator.MapData{
		"username": []string{"required", "between:3,5"},
		"email":    []string{"required", "min:4", "max:20", "email"},
		"web":      []string{"url"},
		"age":      []string{"required"},
		"agree":    []string{"required"},
	}

	opts := govalidator.Options{
		Request: r,
		Data:    &user,
		Rules:   rules,
	}

	v := govalidator.New(opts)
	e := v.ValidateJSON()
	fmt.Println(user) // your incoming JSON data in Go data struct
	err := map[string]interface{}{"validationError": e}
	w.Header().Set("Content-type", "application/json")
	json.NewEncoder(w).Encode(err)
}

func main() {
	http.HandleFunc("/", handler)
	fmt.Println("Listening on port: 9000")
	http.ListenAndServe(":9000", nil)
}

Response

{
    "validationError": {
        "age": [
            "The age field is required"
        ],
        "agree": [
            "The agree field is required"
        ],
        "email": [
            "The email field is required",
            "The email field must be minimum 4 char",
            "The email field must be a valid email address"
        ],
        "username": [
            "The username field is required",
            "The username field must be between 3 and 5"
        ]
    }
}

Note: When using required rule with number or boolean data, use provided custom type like: Int, Int64, Float32, Float64 or Bool