Trying to convert string to instance variable - rest

Question

I'm new to GO language.
Trying to learn GO by building real web application.
I'm using revel framework.
And here is my resource routes:
GET /resource/:resource Resource.ReadAll
GET /resource/:resource/:id Resource.Read
POST /resource/:resource Resource.Create
PUT /resource/:resource/:id Resource.Update
DELETE /resource/:resource/:id Resource.Delete
for example:
GET /resource/users calls Resource.ReadAll("users")
And this is my Resource controller (it's just a dummy actions for now):
type Resource struct {
*revel.Controller
}
type User struct {
Id int
Username string
Password string
}
type Users struct {}
func (u Users) All() string {
return "All"
}
func (c Resource) ReadAll(resource string) revel.Result {
fmt.Printf("GET %s", resource)
model := reflect.New(resource)
fmt.Println(model.All())
return nil
}
I'm trying get instance of Users struct by converting resource string to object to call All function.
and the error:
cannot use resource (type string) as type reflect.Type in argument to
reflect.New: string does not implement reflect.Type (missing Align
method)
I'm new to GO please don't judge me :)

Answer 1

Your problem is here:
model := reflect.New(resource)
You can't instantiate a type from a string that way. You need to either use a switch there and do stuff depending on the model:
switch resource {
case "users":
model := &Users{}
fmt.Println(model.All())
case "posts":
// ...
}
Or use reflect correctly. Something like:
var types = map[string]reflect.Type{
"users": reflect.TypeOf(Users{}) // Or &Users{}.
}
// ...
model := reflect.New(types[resource])
res := model.MethodByName("All").Call(nil)
fmt.Println(res)