gin how to check whether params was post or not - go

Question

type listParams struct {
Status int `form:"status"`
Keyword string `form:"keyword"`
ShowType int `form:"show_type"`
}
func List(c *gin.Context) {
var ReqData listParams
_ = c.ShouldBind(&ReqData)
// I fetch this by PostForm() to check it empy if it equal to empty string
if stat := c.PostForm("status"); stat == "" {
ReqData.Status = -99
}
// .......
}
In this code, How can I know that was front-end post the status or not?
Because of the default value of go, if I check the reqData.Status == 0, it will always return true if the front-end didn't post it, but In my case, 0 is a meaningful value, So I can't check it by equal to 0.
So am I have the others way to check it?
PS: I tried and found out that gorm will not update the field in struct if I don't assign:
var d &User{} // User is a definition of user table
d.ID = 1
d.Name = "Joy"
// d.Status = 1 // It has this field, but I dont assign it
db.Model(&User{}).updates(&d)
Finally, status won't update to 0(In my understanding, d.Status should be 0)

Answer 1

Use a pointer type to circumvent the 0 default value:
type listParams struct {
Status &int `form:"status"`
Keyword string `form:"keyword"`
ShowType int `form:"show_type"`
}
The check if d.Status is nil, otherwise get the associated value

Answer 2

I think this constraint raises the need for having a sole public way to construct User.
type user struct { Status int Keyword string ShowTypeint}
func NewUser() (*user) { return &user{Status: -1} }
That way you ensure that user struct is only constructed through NewUser having Status default value Status always equal to -1.