Merge pull request #10 from iFaceless/support-default-value

✨ feat: support default value

USERGUIDE.md

@@ -83,6 +83,20 @@ type UserSchema struct {
 
 ```
 
+### Set Default Value for Field: `default`
+
+Only works for types: pointer/slice/map. For basic types (integer, string, bool), default value will be converted and set to field directly. For complex types (eg. map/slice/pointer to custom struct), set default to `AUTO_INIT`, portal will initialize field to its zero value. 
+
+```go
+type ContentSchema struct {
+	BizID   *string        `json:"biz_id" portal:"default:100"`
+	SkuID   *string        `json:"sku_id"`                             // -> json null
+	Users   []*UserSchema  `json:"users" portal:"default:AUTO_INIT"`   // -> json []
+	Members map[string]int `json:"members" portal:"default:AUTO_INIT"` // -> json {}
+	User    *UserSchema    `json:"user" portal:"default:AUTO_INIT"`
+}
+```
+
 ## Embedding Schema
 ```go
 type PersonSchema struct {

_examples/todo/schema/schema.go

@@ -26,15 +26,17 @@ type UserSchema struct {
 }
 
 type TaskSchema struct {
-	ID           string      `json:"id,omitempty"`
-	Title        string      `json:"title,omitempty"`
-	Description  string      `json:"description,omitempty" portal:"meth:GetDescription;async"`
-	Description1 string      `json:"description1,omitempty" portal:"meth:GetDescription;async"`
-	Description2 string      `json:"description2,omitempty" portal:"meth:GetDescription;async"`
-	Description3 string      `json:"description3,omitempty" portal:"meth:GetDescription;async"`
-	User         *UserSchema `json:"user,omitempty" portal:"nested"`
-	SimpleUser   *UserSchema `json:"simple_user,omitempty" portal:"nested;only:Name;attr:User"`
-	Unknown      string      `json:"unknown"`
+	ID               string        `json:"id,omitempty"`
+	Title            string        `json:"title,omitempty"`
+	Description      string        `json:"description,omitempty" portal:"meth:GetDescription;async"`
+	Description1     string        `json:"description1,omitempty" portal:"meth:GetDescription;async"`
+	Description2     string        `json:"description2,omitempty" portal:"meth:GetDescription;async"`
+	Description3     string        `json:"description3,omitempty" portal:"meth:GetDescription;async"`
+	User             *UserSchema   `json:"user,omitempty" portal:"nested"`
+	SimpleUser       *UserSchema   `json:"simple_user,omitempty" portal:"nested;only:Name;attr:User"`
+	Unknown          string        `json:"unknown"`
+	UsersWithDefault []*UserSchema `json:"users_with_default" portal:"nested;default:AUTO_INIT"`
+	UserWithDefault  *UserSchema   `json:"user_with_default" portal:"nested;default:AUTO_INIT"`
 }
 
 func (ts *TaskSchema) GetDescription(model *model.TaskModel) (string, error) {

chell.go

@@ -73,7 +73,9 @@ func (c *Chell) DumpWithContext(ctx context.Context, dst, src interface{}) error
 		return c.dumpMany(
 			ctx, dst, src,
 			extractFilterNodeNames(c.onlyFieldFilters[0], nil),
-			extractFilterNodeNames(c.excludeFieldFilters[0], &extractOption{ignoreNodeWithChildren: true}))
+			extractFilterNodeNames(c.excludeFieldFilters[0], &extractOption{ignoreNodeWithChildren: true}),
+			"",
+		)
 	} else {
 		toSchema := newSchema(dst).withFieldAliasMapTagName(c.fieldAliasMapTagName)
 		toSchema.setOnlyFields(extractFilterNodeNames(c.onlyFieldFilters[0], nil)...)
@@ -210,8 +212,13 @@ func (c *Chell) dumpAsyncFields(ctx context.Context, dst *schema, src interface{
 
 func (c *Chell) dumpField(ctx context.Context, field *schemaField, value interface{}) error {
 	if isNil(value) {
-		logger.Warnf("[portal.chell] cannot get value for field %s, current input value is %v", field, value)
-		return nil
+		if field.hasDefaultValue() {
+			value = field.defaultValue()
+			logger.Infof("[portal.chell] use default value for field `%s`", field)
+		} else {
+			logger.Warnf("[portal.chell] cannot get value for field `%s`, current input value is %v", field, value)
+			return nil
+		}
 	}
 
 	if !field.isNested() {
@@ -259,6 +266,7 @@ func (c *Chell) dumpFieldNestedMany(ctx context.Context, field *schemaField, src
 		src,
 		field.nestedOnlyNames(c.onlyFieldFilters[depth]),
 		field.nestedExcludeNames(c.excludeFieldFilters[depth]),
+		field.String(),
 	)
 	if err != nil {
 		return err
@@ -279,14 +287,18 @@ func (c *Chell) dumpFieldNestedMany(ctx context.Context, field *schemaField, src
 	return nil
 }
 
-func (c *Chell) dumpMany(ctx context.Context, dst, src interface{}, onlyFields, excludeFields []string) error {
+func (c *Chell) dumpMany(ctx context.Context, dst, src interface{}, onlyFields, excludeFields []string, field string) error {
 	rv := reflect.ValueOf(src)
 	if rv.Kind() == reflect.Ptr {
 		rv = reflect.Indirect(rv)
 	}
 
 	if rv.Kind() != reflect.Slice {
-		panic("input src must be a slice")
+		if field != "" {
+			panic(fmt.Sprintf("input src must be a slice, current processing field is `%s`", field))
+		} else {
+			panic(fmt.Sprintf("input src must be a slice"))
+		}
 	}
 
 	schemaSlice := reflect.Indirect(reflect.ValueOf(dst))

field.go

@@ -170,6 +170,36 @@ func (f *schemaField) hasConstValue() bool {
 	return f.tagHasOption("CONST")
 }
 
+func (f *schemaField) defaultValue() interface{} {
+	val, ok := f.settings["DEFAULT"]
+	if !ok {
+		return nil
+	}
+
+	var defaultValue interface{}
+	if val == "AUTO_INIT" {
+		// just initialize this field, now support ptr/slice/map
+		typ := reflect.TypeOf(f.Value())
+		switch typ.Kind() {
+		case reflect.Ptr:
+			defaultValue = reflect.New(typ.Elem()).Interface()
+		case reflect.Slice:
+			defaultValue = reflect.MakeSlice(typ, 0, 0).Interface()
+		case reflect.Map:
+			defaultValue = reflect.MakeMap(typ).Interface()
+		default:
+			defaultValue = reflect.New(typ).Elem().Interface()
+		}
+		return defaultValue
+	}
+
+	return val
+}
+
+func (f *schemaField) hasDefaultValue() bool {
+	return f.tagHasOption("DEFAULT")
+}
+
 func (f *schemaField) tagHasOption(opt string) bool {
 	if _, ok := f.settings[opt]; ok {
 		return true

field_test.go

@@ -143,6 +143,36 @@ func TestField_ConstValue(t *testing.T) {
 	assert.False(t, f.hasConstValue())
 }
 
+func TestField_DefaultValue(t *testing.T) {
+	type UserSchema struct {
+		ID string
+	}
+
+	type FooSchema struct {
+		ID       *string           `json:"id" portal:"default:100"`
+		Settings map[string]string `json:"settings" portal:"default:AUTO_INIT"`
+		User     *UserSchema       `json:"user" portal:"default:AUTO_INIT"`
+		Users    []*UserSchema     `json:"users" portal:"default:AUTO_INIT"`
+	}
+
+	schema := newSchema(&FooSchema{})
+	f := newField(schema, schema.innerStruct().Field("ID"))
+	assert.Equal(t, "100", f.defaultValue())
+	assert.True(t, f.hasDefaultValue())
+
+	f = newField(schema, schema.innerStruct().Field("Settings"))
+	assert.Equal(t, map[string]string{}, f.defaultValue())
+	assert.True(t, f.hasDefaultValue())
+
+	f = newField(schema, schema.innerStruct().Field("User"))
+	assert.Equal(t, &UserSchema{}, f.defaultValue())
+	assert.True(t, f.hasDefaultValue())
+
+	f = newField(schema, schema.innerStruct().Field("Users"))
+	assert.Equal(t, make([]*UserSchema, 0), f.defaultValue())
+	assert.True(t, f.hasDefaultValue())
+}
+
 func TestField_Async(t *testing.T) {
 	type FooSchema struct {
 		ID   int