Flattening marshalled JSON structs with anonymous members in Go

Question

Given the following code: (reproduced here at play.golang.org.)

package main

import (
    "encoding/json"
    "fmt"
)

type User struct {         


        

Answer 1

One approach which I've worked through involves the use of methods on types. Please see http://play.golang.org/p/bPWB4ryDQn for more details.

Basically, you work the problem from the opposite angle -- instead of "encapsulating" a base type into a Hateoas type, you instead incorporate the required map in each of your base types. Then, implement a method on each of those base types, which is responsible for updating the Links field accordingly.

This produces the intended result, and with only marginal source code boiler-plate.

{
    "id": 123,
    "name": "James Dean",
    "_links": {
        "self": "http://user/123"
    }
}
{
    "id": 456,
    "userId": 123,
    "_links": {
        "self": "http://session/456"
    }
}

I believe any other way than this, particularly if you persue the embed-and-extend approach, will require implementing a custom marshaler (http://golang.org/pkg/encoding/json/#Marshaler) and will likely require the use of the reflect package as well, especially since anything is of type interface{}.