Gin time_format tag not work with json tag

I read this example from official docs: https://gin-gonic.com/docs/examples/custom-validators/

package main

import (
    "net/http"
    "time"

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

// Booking contains binded and validated data.
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"`
}

var bookableDate validator.Func = func(fl validator.FieldLevel) bool {
    date, ok := fl.Field().Interface().(time.Time)
    if ok {
        today := time.Now()
        if today.After(date) {
            return false
        }
    }
    return true
}

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

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

    route.GET("/bookable", getBookable)
    route.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()})
    }
}

And I try to apply time_format tag to my struct ``` package teacher_form

import "time"

type CreateTeacherFormRequest struct { Birth time.Time json:"birth" form:"birth" binding:"required" time_format:"2006-01-02" }

```

When I send POST request using formData , the validation work well. But if I send POST request with json payload. Gin fw not validate anything at all. It seem like the time_format only work with formData? How can I validate POST request input field with the specific time format. For example just only date: 2006-01-02.

Comment From: RedCrazyGhost

Since golang json uses the RFC3339 specification, you can access it with the following request parameters

{
    "birth":"2024-06-17T15:04:05+08:00"
}

see https://github.com/gin-gonic/gin/issues/1193