Partly JSON unmarshal into a map in Go

Question

My websocket server will receive and unmarshal JSON data. This data will always be wrapped in an object with key/value pairs. The key-string will act as value identifier, telling the Go server what kind of value it is. By knowing what type of value, I can then proceed to JSON unmarshal the value into the correct type of struct. Each json-object might contain multiple key/value pairs. Example JSON: ``` { "sendMsg":{"user":"ANisus","msg":"Trying to send a message"}, "say":"Hello" } ``` Is there any easy way using the `"encoding/json"` package to do this? ``` package main import ( "encoding/json" "fmt" ) // the struct for the value of a "sendMsg"-command type sendMsg struct { user string msg string } // The type for the value of a "say"-command type say string func main(){ data := []byte(`{"sendMsg":{"user":"ANisus","msg":"Trying to send a message"},"say":"Hello"}`) // This won't work because json.MapObject([]byte) doesn't exist objmap, err := json.MapObject(data) // This is what I wish…

Accepted Answer

This can be accomplished by Unmarshaling into a `map[string]json.RawMessage`.

```
var objmap map[string]json.RawMessage
err := json.Unmarshal(data, &objmap)
```

To further parse `sendMsg`, you could then do something like:

```
var s sendMsg
err = json.Unmarshal(objmap["sendMsg"], &s)
```

For `say`, you can do the same thing and unmarshal into a string:

```
var str string
err = json.Unmarshal(objmap["say"], &str)
```

EDIT: Keep in mind you will also need to export the variables in your sendMsg struct to unmarshal correctly. So your struct definition would be:

```
type sendMsg struct {
    User string
    Msg  string
}
```

Example: https://play.golang.org/p/OrIjvqIsi4-

Partly JSON unmarshal into a map in Go

Solution

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