Merge pull request #4 from Osendo/pr

feat: add ignore struct tag

Author: dranikpg

README.md

@@ -79,6 +79,23 @@ type UserDto struct {
 }
 ```
 
+##### Ignored fields
+
+If you need to ignore any of the structure fields, you can apply the structure tag - dto:ignore
+
+```go
+type Order struct {
+	Id string
+
+	json.Marshaler   `dto:"ignore"`
+	json.Unmarshaler `dto:"ignore"`
+}
+
+type OrderDto struct {
+	Id string
+}
+```
+
 #### Mapper instances
 
 Local mapper instances can be used to add conversion and inspection functions. Mappers don't change their internal state during mapping, so they can be reused at any time.

dto.go

@@ -17,6 +17,7 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
+	"strings"
 )
 
 type structValueMap = map[string]reflect.Value
@@ -31,6 +32,8 @@ var mapperPtrRfType = reflect.TypeOf((*Mapper)(nil))
 type convertFuncClosure = func(reflect.Value, *Mapper) (reflect.Value, error)
 type inspectFuncClosure = func(reflect.Value, reflect.Value, *Mapper) error
 
+const structTag = "dto"
+
 // NoValidMappingError indicates that no valid mapping was found
 type NoValidMappingError struct {
 	ToType   reflect.Type
@@ -55,6 +58,11 @@ func collectStructFields(rfValue reflect.Value, rfType reflect.Type, fields stru
 	for i := 0; i < rfType.NumField(); i++ {
 		fieldValue := rfValue.Field(i)
 		fieldType := rfType.Field(i)
+		if tags, ok := fieldType.Tag.Lookup(structTag); ok {
+			if strings.Contains(tags, "ignore") {
+				continue
+			}
+		}
 		if fieldType.Anonymous {
 			collectStructFields(fieldValue, fieldType.Type, fields)
 		} else {

dto_test.go

@@ -1,6 +1,7 @@
 package dto
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"reflect"
@@ -37,6 +38,17 @@ type User struct {
 	Password RawPassword
 }
 
+type Order struct {
+	Id string
+
+	json.Marshaler   `dto:"ignore"`
+	json.Unmarshaler `dto:"ignore"`
+}
+
+type OrderDto struct {
+	Id string
+}
+
 // ==================================== Data for tests ========================
 
 var commonProducts = []Product{
@@ -346,6 +358,13 @@ func TestPointerCases(t *testing.T) {
 	}
 }
 
+func TestStructureTagIgnoreCase(t *testing.T) {
+	order := Order{Id: "test"}
+	var outOrder OrderDto
+	Map(&outOrder, order)
+	assert.Equal(t, order.Id, outOrder.Id)
+}
+
 // ==================================== Benchmarks ============================
 
 type benchCart = struct {

go.sum

@@ -5,6 +5,7 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=