How do we return the entire order and its partials (API design)?

To return a full order and its partial data via API, you can use a REST approach with different endpoints or query parameters.

For example:

• GET /orders/{id} — returns the full order with details.
• GET /orders/{id}?fields=items,total — returns only the specified fields (partial).

Or use GraphQL, where the client specifies which fields it needs.

In Go, this can be implemented as follows:

func GetOrder(w http.ResponseWriter, r *http.Request) {
    id := mux.Vars(r)["id"]
    fields := r.URL.Query().Get("fields")

    order := fetchOrderFromDB(id)

    if fields != "" {
        // Parse fields and form response with required fields
        partialResponse := filterOrderFields(order, fields)
        json.NewEncoder(w).Encode(partialResponse)
        return
    }

    json.NewEncoder(w).Encode(order)
}

This approach allows flexible data delivery based on client requests.