How to parse weird JSON in go

Question

I'm trying to parse the json below in go, but struggling to find the type or struct to decode into. I don't have any control over the format and the stocks returned might be different for each call, so I can't have a type named AAPL or TSLA. I ultimately want an array/list of objects with the data inside the 'quote' section. Something like:

type Stock struct {
  Symbol string
  CompanyName string
  latestPrice float64
}

Any thoughts?

{
  "AAPL": {
    "quote": {
      "symbol": "AAPL",
      "companyName": "Apple, Inc.",
      "open": 308,
      "close": 315.01,
      "high": 317.05,
      "low": 307.24,
      "latestPrice": 315.01,
      "marketCap": 1365360443400,
      "peRatio": 24.49,
      "week52High": 327.85,
      "week52Low": 170.27
    }
  },
  "TSLA": {
    "quote": {
      "symbol": "TSLA",
      "companyName": "Tesla, Inc.",
      "open": 790.51,
      "close": 811.29,
      "high": 824,
      "low": 785,
      "latestPrice": 811.29,
      "marketCap": 150389638590,
      "peRatio": -963.76,
      "week52High": 968.99,
      "week52Low": 176.99
    }
  }
}

There's nothing weird about that json. What's wrong with decoding it into the obvious structure and transforming the data afterwards? — JimB, May 12 '20 at 01:55
[Deserialize json object into dynamic object using Json.net](https://stackoverflow.com/q/4535840/8967612) — 41686d6564 stands w. Palestine, May 12 '20 at 01:55
You have a `C#` and a `go` tag, you might want to remove the `C#` one — Seraf, May 12 '20 at 02:28

score 5 · Accepted Answer · answered May 12 '20 at 04:11

First you have to export all your fields, then you can use a map whenever the field names are not known up front. After unmarshaling you can then range over the map and put the data to whatever other structure you would like.

type Stock struct {
    Symbol      string
    CompanyName string
    LatestPrice float64
}

func main() {
    var m map[string]struct{ Quote Stock }
    if err := json.Unmarshal(data, &m); err != nil {
        panic(err)
    }

    var list []Stock
    for _, v := range m {
        list = append(list, v.Quote)
    }

    fmt.Println(list)
}

https://play.golang.com/p/ZXlrWWWgxvB

You should probably put this logic in a custom unmarshal function. — Tarun Khandelwal, May 12 '20 at 20:41

How to parse weird JSON in go

1 Answers1