What will be the structure representation of the following json data in golang?

Question

{
  "devices": [
    {
      "id": 20081691,
      "targetIp": "10.1.1.1",
      "iops": "0.25 IOPS per GB",
      "capacity": 20,
      "allowedVirtualGuests": [
        {
          "Name": "akhil1"
        },
        {
          "Name": "akhil2"
        }
      ]
    }
  ]
}

How to write a structure representation of this JSON data so that I can add and delete devices to the list. I tried with the different structure representations but nothing is working. Below is one of the example I have tried with a similar kind of json data. I am not able to add new data to it. The structure representation and the way the append is done might be wrong here

package main

import (
    "encoding/json"
    "fmt"
)

type Person struct {
    ID        string   `json:"id,omitempty"`
    Firstname string   `json:"firstname,omitempty"`
    Lastname  string   `json:"lastname,omitempty"`
    Address   []Address `json:"address,omitempty"`
}

type Address[] struct {
    City  string `json:"city,omitempty"`

}


func main() {

var people []Person
people = append(people, Person{ID: "1", Firstname: "Nic", Lastname: "Raboy", Address: []Address{{City: "Dublin"},{ City: "CA"}}} )
b, err := json.Marshal(people)
    if err != nil {
        fmt.Println("json err:", err)
    }
    fmt.Println(string(b))
}

score 0 · Answer 1 · answered Mar 03 '17 at 05:26

0

you can use struct tag like json:"id", try struct below:

type Data struct {
        Devices []struct {
                Id                   int    `json:"id"`
                IP                   string `json:"targetIp"`
                IOPS                 string `json:"iops"`
                Capacity             int    `json:"capacity"`
                AllowedVirtualGuests []struct {
                        Name string `json:"Name"`
                } `json:"allowedVirtualGuests"`
        } `json:"devices"`
}

answered Mar 03 '17 at 05:26

zzn

2,376
16
30

Thanks. But how to add new devices json data? – Akhil Reddy Mar 03 '17 at 05:30
add device to the struct, then marshal it. – zzn Mar 03 '17 at 05:31
can we do that using the append method which is used in the above code – Akhil Reddy Mar 03 '17 at 05:33
Can you once paste the the append function line . I tried but im doing something wrong – Akhil Reddy Mar 03 '17 at 06:13

keno · Accepted Answer · 2017-03-03T14:00:47.813

It will be below. This was generated using the excellent JSON-to-GO tool:

type MyStruct struct {
    Devices []struct {
        ID                   int    `json:"id"`
        TargetIP             string `json:"targetIp"`
        Iops                 string `json:"iops"`
        Capacity             int    `json:"capacity"`
        AllowedVirtualGuests []struct {
            Name string `json:"Name"`
        }                           `json:"allowedVirtualGuests"`
    }                               `json:"devices"`
}

To simplify that though, you can break it into smaller structs for readability. An example is below:

package main

import "fmt"

type VirtualGuest struct {
    Name string `json:"Name"`
}

type Device struct {
    ID                   int            `json:"id"`
    TargetIP             string         `json:"targetIp"`
    Iops                 string         `json:"iops"`
    Capacity             int            `json:"capacity"`
    AllowedVirtualGuests []VirtualGuest `json:"allowedVirtualGuests"`
}

type MyStruct struct {
    Devices []Device `json:"devices"`
}

func main() {

    var myStruct MyStruct

    // Add a MyStruct
    myStruct.Devices = append(myStruct.Devices, Device{
        ID:1,
        TargetIP:"1.2.3.4",
        Iops:"iops",
        Capacity:1,
        AllowedVirtualGuests:[]VirtualGuest{
            VirtualGuest{
                Name:"guest 1",
            },
            VirtualGuest{
                Name:"guest 2",
            },
        },
    })

    fmt.Printf("MyStruct: %v\n", myStruct)
}

Thank You so much. Can we do the same by defining AllowedVirtualGuests field as []struct instead of AllowedVirtualGuests []VirtualGuest — Akhil Reddy, Mar 03 '17 at 08:38
Should be able to. Refer to an existing answer: http://stackoverflow.com/questions/32531854/how-to-initialize-nested-structure-array-in-golang — keno, Mar 03 '17 at 14:09

What will be the structure representation of the following json data in golang?

2 Answers2