How to unmarshal JSON with unknown fieldnames to struct [duplicate]

Answer 1

Simply use a map if you don't know the key, and the value type of the map may be the struct describing the structure:

type mData struct {
    KnownField1 [][5]int `json:"known_field_1"`
    KnownField2 [][5]int `json:"known_field_2"`
    KnownField3 [][5]int `json:"known_field_3"`
}

Note that you must export the fields for this to work!

And the unmarshaling code:

var data map[string]mData
if err := json.Unmarshal(body, &data); err != nil {
    panic(err)
}

fmt.Println(data)
for k, v := range data {
    fmt.Println(k, v)
}

Output (try it on the Go Playground):

map[unknown_field:{[[1 2 3 4 5] [10 20 30 40 50] [100 200 300 400 500]] [[11 21 31 41 51]] [[12 22 32 42 52] [14 44 34 44 54]]}]
unknown_field {[[1 2 3 4 5] [10 20 30 40 50] [100 200 300 400 500]] [[11 21 31 41 51]] [[12 22 32 42 52] [14 44 34 44 54]]}

See related questions:

How to parse/deserlize a dynamic JSON in Golang

Unmarshal JSON with unknown fields

Unmarshal json string to a struct that have one element of the struct itself

JSON Nested dynamic structures Go decoding