feat: httpx.Parse supports parsing structures that implement the Unmarshaler interface

core/mapping/unmarshaler.go

@@ -218,7 +218,8 @@
 }
 
 func (u *Unmarshaler) fillSliceFromString(fieldType reflect.Type, value reflect.Value,
-	mapValue any, fullName string) error {
+	mapValue any, fullName string,
+) error {
 	var slice []any
 	switch v := mapValue.(type) {
 	case fmt.Stringer:
@@ -248,7 +249,8 @@
 }
 
 func (u *Unmarshaler) fillSliceValue(slice reflect.Value, index int,
-	baseKind reflect.Kind, value any, fullName string) error {
+	baseKind reflect.Kind, value any, fullName string,
+) error {
 	if value == nil {
 		return errNilSliceElement
 	}
@@ -286,7 +288,8 @@
 }
 
 func (u *Unmarshaler) fillSliceWithDefault(derefedType reflect.Type, value reflect.Value,
-	defaultValue, fullName string) error {
+	defaultValue, fullName string,
+) error {
 	baseFieldType := Deref(derefedType.Elem())
 	baseFieldKind := baseFieldType.Kind()
 	defaultCacheLock.Lock()
@@ -400,7 +403,8 @@
 }
 
 func (u *Unmarshaler) parseOptionsWithContext(field reflect.StructField, m Valuer, fullName string) (
-	string, *fieldOptionsWithContext, error) {
+	string, *fieldOptionsWithContext, error,
+) {
 	key, options, err := parseKeyAndOptions(u.key, field)
 	if err != nil {
 		return "", nil, err
@@ -441,7 +445,8 @@
 }
 
 func (u *Unmarshaler) processAnonymousField(field reflect.StructField, value reflect.Value,
-	m valuerWithParent, fullName string) error {
+	m valuerWithParent, fullName string,
+) error {
 	key, options, err := u.parseOptionsWithContext(field, m, fullName)
 	if err != nil {
 		return err
@@ -459,7 +464,8 @@
 }
 
 func (u *Unmarshaler) processAnonymousFieldOptional(field reflect.StructField, value reflect.Value,
-	key string, m valuerWithParent, fullName string) error {
+	key string, m valuerWithParent, fullName string,
+) error {
 	derefedFieldType := Deref(field.Type)
 
 	switch derefedFieldType.Kind() {
@@ -471,7 +477,8 @@
 }
 
 func (u *Unmarshaler) processAnonymousFieldRequired(field reflect.StructField, value reflect.Value,
-	m valuerWithParent, fullName string) error {
+	m valuerWithParent, fullName string,
+) error {
 	fieldType := field.Type
 	maybeNewValue(fieldType, value)
 	derefedFieldType := Deref(fieldType)
@@ -495,7 +502,8 @@
 }
 
 func (u *Unmarshaler) processAnonymousStructFieldOptional(fieldType reflect.Type,
-	value reflect.Value, key string, m valuerWithParent, fullName string) error {
+	value reflect.Value, key string, m valuerWithParent, fullName string,
+) error {
 	var filled bool
 	var required int
 	var requiredFilled int
@@ -536,7 +544,8 @@
 }
 
 func (u *Unmarshaler) processField(field reflect.StructField, value reflect.Value,
-	m valuerWithParent, fullName string) error {
+	m valuerWithParent, fullName string,
+) error {
 	if usingDifferentKeys(u.key, field) {
 		return nil
 	}
@@ -549,13 +558,16 @@
 }
 
 func (u *Unmarshaler) processFieldNotFromString(fieldType reflect.Type, value reflect.Value,
-	vp valueWithParent, opts *fieldOptionsWithContext, fullName string) error {
+	vp valueWithParent, opts *fieldOptionsWithContext, fullName string,
+) error {
 	derefedFieldType := Deref(fieldType)
 	typeKind := derefedFieldType.Kind()
 	mapValue := vp.value
 	valueKind := reflect.TypeOf(mapValue).Kind()
 
 	switch {
+	case valueKind == reflect.String && typeKind == reflect.Struct && fieldType.Implements(reflect.TypeOf((*json.Unmarshaler)(nil)).Elem()):
+		return u.fillCustomUnmarshalerStruct(fieldType, value, mapValue)
 	case valueKind == reflect.Map && typeKind == reflect.Struct:
 		mv, ok := mapValue.(map[string]any)
 		if !ok {
@@ -581,8 +593,24 @@
 	}
 }
 
+func (u *Unmarshaler) fillCustomUnmarshalerStruct(fieldType reflect.Type, value reflect.Value, mapValue any) error {
+	if !value.CanSet() {
+		return errValueNotSettable
+	}
+	baseType := Deref(fieldType)
+	target := reflect.New(baseType)
+
+	params := make([]reflect.Value, 1)
+	params[0] = reflect.ValueOf([]byte(mapValue.(string)))
+	target.MethodByName("UnmarshalJSON").Call(params)
+
+	value.Set(target)
+	return nil
+}
+
 func (u *Unmarshaler) processFieldPrimitive(fieldType reflect.Type, value reflect.Value,
-	mapValue any, opts *fieldOptionsWithContext, fullName string) error {
+	mapValue any, opts *fieldOptionsWithContext, fullName string,
+) error {
 	typeKind := Deref(fieldType).Kind()
 	valueKind := reflect.TypeOf(mapValue).Kind()
 
@@ -603,7 +631,8 @@
 }
 
 func (u *Unmarshaler) processFieldPrimitiveWithJSONNumber(fieldType reflect.Type, value reflect.Value,
-	v json.Number, opts *fieldOptionsWithContext, fullName string) error {
+	v json.Number, opts *fieldOptionsWithContext, fullName string,
+) error {
 	baseType := Deref(fieldType)
 	typeKind := baseType.Kind()
 
@@ -656,7 +685,8 @@
 }
 
 func (u *Unmarshaler) processFieldStruct(fieldType reflect.Type, value reflect.Value,
-	m valuerWithParent, fullName string) error {
+	m valuerWithParent, fullName string,
+) error {
 	if fieldType.Kind() == reflect.Ptr {
 		baseType := Deref(fieldType)
 		target := reflect.New(baseType).Elem()
@@ -673,7 +703,8 @@
 }
 
 func (u *Unmarshaler) processFieldTextUnmarshaler(fieldType reflect.Type, value reflect.Value,
-	mapValue any) (bool, error) {
+	mapValue any,
+) (bool, error) {
 	var tval encoding.TextUnmarshaler
 	var ok bool
 
@@ -701,7 +732,8 @@
 }
 
 func (u *Unmarshaler) processFieldWithEnvValue(fieldType reflect.Type, value reflect.Value,
-	envVal string, opts *fieldOptionsWithContext, fullName string) error {
+	envVal string, opts *fieldOptionsWithContext, fullName string,
+) error {
 	if err := validateValueInOptions(envVal, opts.options()); err != nil {
 		return err
 	}
@@ -731,7 +763,8 @@
 }
 
 func (u *Unmarshaler) processNamedField(field reflect.StructField, value reflect.Value,
-	m valuerWithParent, fullName string) error {
+	m valuerWithParent, fullName string,
+) error {
 	if !field.IsExported() {
 		return nil
 	}
@@ -778,7 +811,8 @@
 }
 
 func (u *Unmarshaler) processNamedFieldWithValue(fieldType reflect.Type, value reflect.Value,
-	vp valueWithParent, key string, opts *fieldOptionsWithContext, fullName string) error {
+	vp valueWithParent, key string, opts *fieldOptionsWithContext, fullName string,
+) error {
 	mapValue := vp.value
 	if mapValue == nil {
 		if opts.optional() {
@@ -813,7 +847,8 @@
 }
 
 func (u *Unmarshaler) processNamedFieldWithValueFromString(fieldType reflect.Type, value reflect.Value,
-	mapValue any, key string, opts *fieldOptionsWithContext, fullName string) error {
+	mapValue any, key string, opts *fieldOptionsWithContext, fullName string,
+) error {
 	valueKind := reflect.TypeOf(mapValue).Kind()
 	if valueKind != reflect.String {
 		return fmt.Errorf("the value in map is not string, but %s", valueKind)
@@ -842,7 +877,8 @@
 }
 
 func (u *Unmarshaler) processNamedFieldWithoutValue(fieldType reflect.Type, value reflect.Value,
-	opts *fieldOptionsWithContext, fullName string) error {
+	opts *fieldOptionsWithContext, fullName string,
+) error {
 	derefedType := Deref(fieldType)
 	fieldKind := derefedType.Kind()
 	if defaultValue, ok := opts.getDefault(); ok {
@@ -984,7 +1020,8 @@
 }
 
 func fillPrimitive(fieldType reflect.Type, value reflect.Value, mapValue any,
-	opts *fieldOptionsWithContext, fullName string) error {
+	opts *fieldOptionsWithContext, fullName string,
+) error {
 	if !value.CanSet() {
 		return errValueNotSettable
 	}
@@ -1013,7 +1050,8 @@
 }
 
 func fillWithSameType(fieldType reflect.Type, value reflect.Value, mapValue any,
-	opts *fieldOptionsWithContext) error {
+	opts *fieldOptionsWithContext,
+) error {
 	if !value.CanSet() {
 		return errValueNotSettable
 	}

rest/httpx/requests_test.go

@@ -1,6 +1,7 @@
 package httpx
 
 import (
+	"bytes"
 	"errors"
 	"net/http"
 	"net/http/httptest"
@@ -515,3 +516,23 @@ func (m mockRequest) Validate() error {
 
 	return nil
 }
+
+type mockCustomUnmarshalerStruct struct {
+	Name string
+}
+
+func (m *mockCustomUnmarshalerStruct) UnmarshalJSON(b []byte) error {
+	m.Name = string(b)
+	return nil
+}
+
+func TestCustomUnmarshalerStructRequest(t *testing.T) {
+	reqBody := `{"name": "hello"}`
+	r := httptest.NewRequest(http.MethodPost, "/a", bytes.NewReader([]byte(reqBody)))
+	r.Header.Set("Content-Type", "application/json")
+	v := struct {
+		Foo *mockCustomUnmarshalerStruct `json:"name"`
+	}{}
+	assert.Nil(t, Parse(r, &v))
+	assert.Equal(t, "hello", v.Foo.Name)
+}