Golang Structs/Interfaces - go

Question

I'm trying to do something to bring the SQL results dynamically structure, basically I want to run a function by passing the rows and the structure(to get the data type and make one) and return in interface array.
Anyone know how I can do?
I dont want pass the direct "User" struct as param.. that is not dynamically
type User struct{
Id_user int `json:"id_user"`
Name string `json:"name"`
Email string `json:"email"`
Username string `json: "username"`
}
func main() {
var user User
rows, _ := db.Query("SELECT id_user, name, email, username FROM users")
json.NewEncoder(w).Encode(StructRow(user, rows))
}
func StructRow(u interface{}, rows *sql.Rows)[]interface{}{
var data []interface{}
for rows.Next() {
//How i can create a "user" here, dynamically
//for Example
//var user reflect.TypeOf(u)
_ = rows.Scan(StrutForScan(&user)...)
data = append(data, user)
}
return data
}
func StrutForScan(u interface{}) []interface{} {
val := reflect.ValueOf(u).Elem()
v := make([]interface{}, val.NumField())
for i := 0; i < val.NumField(); i++ {
valueField := val.Field(i)
v[i] = valueField.Addr().Interface()
}
return v
}

Answer 1

Changing your function StructRow to
func StructRow(u interface{}, rows *sql.Rows) []interface{} {
var data []interface{}
for rows.Next() {
t := reflect.TypeOf(u)
val := reflect.New(t).Interface()
errScan := rows.Scan(StrutForScan(val)...)
if errScan != nil {
//proper err handling
}
data = append(data, val)
}
return data
}
will fix it. I guess.
For more on reflect package go to: https://golang.org/pkg/reflect/