Unmarshall json into database json field for postgres

Question

type A struct {
   Id int64
   ContactInfo sql.NullString `sql:"type:json"`
}

Given this json - {"Id": 1, "ContactInfo": {"email1": "[email protected]", "phone1": "2223334444"}}, how do we go about Unmarshaling the json into struct A. ContactInfo is just a simple json data type in postgres. I've looked around, but can't seem to find any easy way. Without any special handling, I simply get an error if I json.Unmarshal (error reads - json: cannot unmarshal object into Go value of type string).

What is desired is to leave ContactInfo untouched as a string so we can send it into postgres directly and postgres will verify if its valid json. However, Id should be unmarshaled and assigned as struct value.

Answer 1

To parse JSON with embedded JSON you need to use a field of type json.RawMessage (and a second struct).

Check out this example for basic usage. You will then have access to the raw field contents for use in your database related structure.