parsing nested JSON with go - go

Question

I am trying to parse a nested json on GO ,
the json looks like this:
{
"id" : 12345656,
"date" : "2018-05-02-18-16-17",
"lists" : [
{
"empoyee_id": "12343",
"name": "User1"
},
{
"contractor_id" : "12343",
"name": "User1"
},
{
"contractor_id" : "12343",
"name": "User1"
}
]
}
My struct
type Result struct {
id int64 `json:"id"`
Date string `json:"date"`
Lists []string `json:"lists"`
}
I am trying to access it using the following:
var result Result
json.Unmarshal(contents, &result)
How can I change the above to access to the employee_id or the contractor_id fields ?

Answer 1

You need to use another type to store the nested data rather than a slice of strings like so:
package main
import (
"fmt"
"encoding/json"
)
var contents string = `{
"id" : 12345656,
"date" : "2018-05-02-18-16-17",
"lists" : [
{
"empoyee_id": "12343",
"name": "User1"
},
{
"contractor_id" : "12343",
"name": "User1"
},
{
"contractor_id" : "12343",
"name": "User1"
}
]
}`
type Result struct {
ID int64 `json:"id"`
Date string `json:"date"`
Lists []Contractor `json:"lists"`
}
type Contractor struct {
ContractorID string `json:"contractor_id"`
EmployeeID string `json:"employee_id"`
Name string `json:"name"`
}
func main() {
var result Result
err := json.Unmarshal([]byte(contents), &result)
if err != nil {
panic(err)
}
fmt.Println(result)
}
Executable:
https://play.golang.org/p/7dYArgz1V8y
If you just want a single ID field on the nested object then you will need to do a custom unmarshal function on the result to work out which ID is present.