gistfile1.txt

package main

import (
        "encoding/json"
        "fmt"
)

type Customer struct {
        ID        int    `json:"id"`
        FirstName string `json:"firstName"`
        LastName  string `json:"lastName"`
}

type SafeCustomer struct {
        Customer
        ID        int    `json:"-"`
}

func main() {
        userInput := []byte(`{"id": 999999, "firstName": "Jane"}`)
        customer := Customer{1, "Joe", "Bloggs"}
        fmt.Println(customer)

        safeCustomer := &SafeCustomer{Customer: customer}
        json.Unmarshal(userInput, &updatedCustomer)

        fmt.Println(customer)
}

func getCustomerByID(id int) *Customer {
        return &Customer{id, "Joe", "Bloggs"}
}