Ginでバリデーションを使ってみる

開発環境は、Windows 10 Pro(64bit) + go version go1.15.3 windows/amd64。

Go言語のWebアプリケーションフレームワークであるGinのバリデーションについてのメモ。

以下、サンプルプログラムを引用します。

package main

import(
"net/http"
"time"
"reflect"

"github.com/gin-gonic/gin"
"github.com/gin-gonic/gin/binding"
"github.com/go-playground/validator/v10"
)

type Booking struct {
	CheckIn  time.Time `form:"check_in" binding:"required,bookabledate" time_format:"2006-01-02"`
	CheckOut time.Time `form:"check_out" binding:"required,gtfield=CheckIn,bookabledate" time_format:"2006-01-02"`
}

func bookableDate(
	v *validator.Validate, topStruct reflect.Value, currentStructOrField reflect.Value,
	field reflect.Value, fieldType reflect.Type, fieldKind reflect.Kind, param string,
) bool {
	if date, ok := field.Interface().(time.Time); ok {
		today := time.Now()
		if today.Year() > date.Year() || today.YearDay() > date.YearDay() {
			return false
		}
	}
	return true
}

func main(){
  r := gin.Default()

  if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
    v.RegisterValidation("bookabledate", bookableDate)
  }

  r.GET("/bookable", getBookable)
  r.Run(":8085")
}

func getBookable(c *gin.Context) {
  var b Booking
  if err := c.ShouldBindWith(&b, binding.Query); err == nil {
    c.JSON(http.StatusOK, gin.H{"message": "Booking dates are valid!"})
  } else {
    c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
  }
}

■参考リンク
カスタムバリデーション