Parsing json without index name in golang

Question

I have a json in the following format

{
    "status_code": 200,
    "status_message": "OK",
    "response": {
        "Messages": [
            "CODE_NOT_AVAILABLE"
        ],
        "UnknownDevices": {
            "": [
                "6",
                "7",
                "8",
                "9",
                "10"
            ]
        }
    }
}

As we see we are missing one index key, after unknownDevices, i am trying to unmarshal this json using golan in the following way

package main

import (
    "encoding/json"
    "fmt"
)

type pushWooshResponse struct {
    Status     int    `json:"status_code"`
    Status_msg string `json:"status_message"`
    Response   response
}

type response struct {
    Message        []string `json:"Messages"`
    UnknownDevices devices
}

type devices struct {
    Udevices []string `json:""`
}

func main() {
    itemInfoR := `{"status_code":200,"status_message":"OK","response":{"Messages":["CODE_NOT_AVAILABLE"],"UnknownDevices":{"devices":["6","7","8","9","10"]}}}`
    itemInfoBytes := []byte(itemInfoR)
    var ItemInfo pushWooshResponse
    er := json.Unmarshal(itemInfoBytes, &ItemInfo)
    if er != nil {
        fmt.Println("Error", er.Error())
    } else {
        fmt.Println(ItemInfo)
    }
}

Output is

{200 OK {[CODE_NOT_AVAILABLE] {[]}}}

Everything is working fine except for the last part, which i am not able to unmarshall this. Can you help me out to umarshal the last part of the json.

Answer 1

There may be other options, but whenever you see strange JSON you can always fall back to implementing your own custom (un)marshalling by implementing json.Unmarshaler and/or json.Marshaler.

Perhaps something like:

type devices struct {
    Udevices []string
}

func (d *devices) UnmarshalJSON(b []byte) error {
    var x map[string][]string
    err := json.Unmarshal(b, &x)
    if err == nil {
        // perhaps check that only a single
        // key exists in the map as well
        d.Udevices = x[""]
    }
    return err
}

func (d devices) MarshalJSON() ([]byte, error) {
    x := map[string][]string{"": d.Udevices}
    return json.Marshal(x)
}

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