Add custom interface base type

mongox/base/getid.go

@@ -18,6 +18,9 @@ func GetID(source interface{}) (id interface{}) {
 		return getStringIDOrPanic(doc)
 	case mongox.ObjectBased:
 		return getObjectOrPanic(doc)
+	case mongox.InterfaceBased:
+		return getInterfaceOrPanic(doc)
+
 	default:
 		panic(fmt.Errorf("source contains malformed document, %v", source))
 	}
@@ -55,3 +58,13 @@ func getObjectOrPanic(source mongox.ObjectBased) (id primitive.D) {
 
 	panic(fmt.Errorf("source contains malformed document, %v", source))
 }
+
+func getInterfaceOrPanic(source mongox.InterfaceBased) (id interface{}) {
+
+	id = source.GetID()
+	if id != nil {
+		return id
+	}
+
+	panic(fmt.Errorf("source contains malformed document, %v", source))
+}

mongox/base/getid_test.go

@@ -6,6 +6,18 @@ import (
 	"go.mongodb.org/mongo-driver/bson/primitive"
 )
 
+type DocWithCustomInterface struct {
+	ID int `bson:"_id" json:"_id" collection:"4"`
+}
+
+func (d *DocWithCustomInterface) GetID() interface{} {
+	return d.ID
+}
+
+func (d *DocWithCustomInterface) SetID(id interface{}) {
+	panic("not implemented")
+}
+
 func TestGetID(t *testing.T) {
 
 	type DocWithObjectID struct {
@@ -21,4 +33,5 @@ func TestGetID(t *testing.T) {
 	GetID(&DocWithObjectID{ObjectID: ObjectID([12]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2})})
 	GetID(&DocWithObject{Object: Object(primitive.D{{"1", "2"}})})
 	GetID(&DocWithString{String: String("foobar")})
+	GetID(&DocWithCustomInterface{ID: 420})
 }