Add merchant specific opaque data container

does not get used in requests towards datatrans but Data map can
contain merchant specific configurations.

client.go

@@ -11,6 +11,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net/http"
+	"strconv"
 	"time"
 )
 
@@ -50,6 +51,9 @@ type OptionMerchant struct {
 	DisableRawJSONBody bool
 	MerchantID         string // basic auth user
 	Password           string // basic auth pw
+	// Data contains merchant specific other IDs or configurations. Keys/Values
+	// from this map are not getting used in requests towards datatrans.
+	Data map[string]interface{}
 }
 
 func (m OptionMerchant) apply(c *Client) error {
@@ -536,3 +540,54 @@ func (c *Client) ReconciliationsSalesBulk(ctx context.Context, sales RequestReco
 	}
 	return &rrs, nil
 }
+
+// GetDataInt returns the int value from the data map or false if not found or failed to convert.
+func (c *Client) GetDataInt(key string) (int, bool) {
+	internalID := c.currentInternalID
+	if !c.internalIDFound {
+		return 0, false
+	}
+	raw, ok := c.merchants[internalID].Data[key]
+	if !ok {
+		return 0, false
+	}
+	switch t := raw.(type) {
+	case string:
+		i, err := strconv.Atoi(t)
+		return i, err == nil
+	case int:
+		return t, true
+	case int64:
+		return int(t), true
+	}
+	return 0, false
+}
+
+// GetDataString returns the string value from the data map or false if not found or failed to convert.
+func (c *Client) GetDataString(key string) (string, bool) {
+	internalID := c.currentInternalID
+	if !c.internalIDFound {
+		return "", false
+	}
+	raw, ok := c.merchants[internalID].Data[key]
+	if !ok {
+		return "", false
+	}
+	switch t := raw.(type) {
+	case string:
+		return t, true
+	case []byte:
+		return string(t), true
+	default:
+		return fmt.Sprintf("%v", t), true
+	}
+}
+
+func (c *Client) GetDataRaw(key string) (interface{}, bool) {
+	internalID := c.currentInternalID
+	if !c.internalIDFound {
+		return nil, false
+	}
+	raw, ok := c.merchants[internalID].Data[key]
+	return raw, ok
+}

client_test.go

@@ -193,3 +193,37 @@ func TestClient_AliasDelete_Error(t *testing.T) {
 		t.Error("errors not equal")
 	}
 }
+
+func TestClient_GetData(t *testing.T) {
+	c, err := datatrans.MakeClient(
+		datatrans.OptionMerchant{
+			InternalID: "", // default
+			MerchantID: "A",
+			Data: map[string]interface{}{
+				"k1": "1",
+			},
+		},
+		datatrans.OptionMerchant{
+			InternalID: "B",
+			MerchantID: "B",
+			Data: map[string]interface{}{
+				"k2": "2",
+			},
+		},
+	)
+	must(t, err)
+	if v, ok := c.GetDataString("k1"); !ok || v != "1" {
+		t.Errorf("wrong value for k1: %#v", v)
+	}
+	if v, ok := c.GetDataInt("k1"); !ok || v != 1 {
+		t.Errorf("wrong value for k1: %#v", v)
+	}
+
+	c2 := c.WithMerchant("B")
+	if v, ok := c2.GetDataString("k2"); !ok || v != "2" {
+		t.Errorf("wrong value for k2: %#v", v)
+	}
+	if v, ok := c2.GetDataInt("k2"); !ok || v != 2 {
+		t.Errorf("wrong value for k2: %#v", v)
+	}
+}