rpc: add server-side NEP-11 tracking API

pkg/rpc/server/tokens.go

@@ -0,0 +1,27 @@
+package server
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/rpc/response/result"
+)
+
+// tokenTransfers is a generic type used to represent NEP-11 and NEP-17 transfers.
+type tokenTransfers struct {
+	Sent     []interface{} `json:"sent"`
+	Received []interface{} `json:"received"`
+	Address  string        `json:"address"`
+}
+
+// nep17TransferToNEP11 adds an ID to provided NEP-17 transfer and returns a new
+// NEP-11 structure.
+func nep17TransferToNEP11(t17 *result.NEP17Transfer, id string) result.NEP11Transfer {
+	return result.NEP11Transfer{
+		Timestamp:   t17.Timestamp,
+		Asset:       t17.Asset,
+		Address:     t17.Address,
+		ID:          id,
+		Amount:      t17.Amount,
+		Index:       t17.Index,
+		NotifyIndex: t17.NotifyIndex,
+		TxHash:      t17.TxHash,
+	}
+}