Return user invoices

and maybe correctly encode the Buffers?

lib/javascriptbuffer.go

@@ -0,0 +1,32 @@
+package lib
+
+import (
+	"encoding/hex"
+	"fmt"
+	"strings"
+)
+
+type JavaScriptBuffer struct {
+	Data []uint8
+}
+
+func (buf *JavaScriptBuffer) MarshalJSON() ([]byte, error) {
+	var array string
+	if buf.Data == nil {
+		array = "null"
+	} else {
+		array = strings.Join(strings.Fields(fmt.Sprintf("%d", buf.Data)), ",")
+	}
+	jsonResult := fmt.Sprintf(`{"type": "Buffer", "data":%s}`, array)
+	return []byte(jsonResult), nil
+}
+
+func ToJavaScriptBuffer(hexString string) (*JavaScriptBuffer, error) {
+	buf := JavaScriptBuffer{}
+	hexArray, err := hex.DecodeString(hexString)
+	if err != nil {
+		return &buf, err
+	}
+	buf.Data = hexArray
+	return &buf, nil
+}