extract JSON from golang's echo request

This is how I did it:

json_map := make(map[string]interface{})
err := json.NewDecoder(c.Request().Body).Decode(&json_map)
if err != nil {
    return err
} else {
    //json_map has the JSON Payload decoded into a map
    cb_type := json_map["type"]
    challenge := json_map["challenge"]