Golang serialize form-urlencoded to object - postgresql

Question

I've made a post request where I'm sending data as JSON and this code creates a new row in the DB.
json.NewDecoder(r.Body).Decode(&user)
DB.Create(&user)
json.NewEncoder(w).Encode(user)
But parsing the form data shows this error
I figured this is how I would read every individual value
for key, value := range r.PostForm {
fmt.Printf("Key:%s, Value:%s\n", key, value)
}
My model looks like this
type User struct {
gorm.Model
FirstName string `json:"firstname"`
LastName string `json:"lastname"`
Email string `json:"email"`
}
How would I convert this to user and insert to DB?

Answer 1

Another way to do it (a bit overengineered, better to use r.FormValue), without having to type the fields again, such as r.FormValue("firstname"), etc if you already know the data, types etc.
func handleUser(w http.ResponseWriter, r *http.Request) {
user := User{}
userType := reflect.TypeOf(user)
for i := 0; i < userType.NumField(); i++ {
// Get the JSON tag of the field, use it for the r.FormValue
f := userType.Field(i).Tag.Get("json")
if f != "" {
reflect.ValueOf(&user).Elem().FieldByName(
userType.Field(i).Name).SetString(r.FormValue(f))
}
}
// DB.Create(&user) need a reference to DB here.
json.NewEncoder(w).Encode(user)
}
Note: This is just an example that will work for string fields, may panic otherwise because it's calling SetString. Additionally, a field may not exist and could panic when trying to access it in the FieldByName(..., but I think your question was geared to this direction of not having to type each field, so leaving it as an example.
The right way to do it, as Cerise Limón pointed out, would be
func handleUser(w http.ResponseWriter, r *http.Request) {
user := User{}
user.FirstName = r.FormValue("firstname")
user.LastName = r.FormValue("lastname")
user.Email = r.FormValue("email")
// DB.Create(&user) need a reference to DB here.
json.NewEncoder(w).Encode(user)
}
Note that you can also add a method for populating the user with the form if you do this in several places, for example
func (u *User) setFormData(r *http.Request) {
u.FirstName = r.FormValue("firstname")
u.LastName = r.FormValue("lastname")
u.Email = r.FormValue("email")
}
And then use it like this
func handleUser(w http.ResponseWriter, r *http.Request) {
user := User{}
user.setFormData(r)
// DB.Create(&user)
json.NewEncoder(w).Encode(user)
}