How to return dynamic type struct in Golang?

Question

I am using Golang Revel for some web project and I did like 12 projects in that so far. In all of them I have a lot of code redundancy because of return types. Look at this two functions:

func (c Helper) Brands() []*models.Brand{      //do some select on rethinkdb and populate correct model     var brands []*models.Brand     rows.All(&brands)      return brands  }  func (c Helper) BlogPosts() []*models.Post{      //do some select on rethinkdb and populate correct model     var posts []*models.Post     rows.All(&posts)      return posts  } 

As you can see they they both returns same type of data (type struct). My idea was just to pass string var like this:

func (c Helper) ReturnModels(modelName string) []*interface{} {      //do rethinkdb select with modelName and return []*interface{} for modelName } 

Like this I can have just one helper for returning data types instead of doing same thing over and over again for different models but same data type.

My questions are:

1. Is this possible at all
2. If yes can you point me to right docs
3. If no, I will be more then happy to return your answer :)

Answer 1

Yes it's possible however your function should return interface{} and not []*interface.

func (c Helper) ReturnModels(modelName string) interface{} {} 

In this case you could use Type Switches and/or Type Assertions to cast the return value into it's original type.

Example

Note: I've never used Revel, but the following snippet should give you an a general idea:

Playground

package main  import "fmt"  type Post struct {     Author  string     Content string }  type Brand struct {     Name string }  var database map[string]interface{}  func init() {     database = make(map[string]interface{})      brands := make([]Brand, 2)     brands[0] = Brand{Name: "Gucci"}     brands[1] = Brand{Name: "LV"}      database["brands"] = brands      posts := make([]Post, 1)     posts[0] = Post{Author: "J.K.R", Content: "Whatever"}      database["posts"] = posts }  func main() {     fmt.Println("List of Brands: ")     if brands, ok := ReturnModels("brands").([]Brand); ok {         fmt.Printf("%v", brands)     }      fmt.Println("\nList of Posts: ")     if posts, ok := ReturnModels("posts").([]Post); ok {         fmt.Printf("%v", posts)     }  }  func ReturnModels(modelName string) interface{} {      return database[modelName] }