Go- Copy all common fields between structs

Question

I have a database that stores JSON, and a server that provides an external API to whereby through an HTTP post, values in this database can be changed. The database is used by different processes internally, and as such have a common naming scheme.

The keys the customer sees are different, but map 1:1 with the keys in the database (there are unexposed keys). For example:

This is in the database:

{ "bit_size": 8, "secret_key": false }

And this is presented to the client:

{ "num_bits": 8 }

The API can change with respect to field names, but the database always has consistent keys.

I have named the fields the same in the struct, with different flags to the json encoder:

type DB struct {
    NumBits int  `json:"bit_size"`
    Secret  bool `json:"secret_key"`
}
type User struct {
    NumBits int `json:"num_bits"`
}

I'm using encoding/json to do the Marshal/Unmarshal.

Is reflect the right tool for this? Is there an easier way since all of the keys are the same? I was thinking some kind of memcpy (if I kept the user fields in the same order).

Answer 1

Couldn't struct embedding be useful here?

package main

import (
    "fmt"
)

type DB struct {
    User
    Secret bool `json:"secret_key"`
}

type User struct {
    NumBits int `json:"num_bits"`
}

func main() {
    db := DB{User{10}, true}
    fmt.Printf("Hello, DB: %+v\n", db)
    fmt.Printf("Hello, DB.NumBits: %+v\n", db.NumBits)
    fmt.Printf("Hello, User: %+v\n", db.User)
}

http://play.golang.org/p/9s4bii3tQ2