unmarshal error text

messenger.go

@@ -198,7 +198,7 @@ func (m *Messenger) ProfileByID(id int64, profileFields []string) (Profile, erro
 
 	err = json.Unmarshal(content, &p)
 	if err != nil {
-		return p, NewUnmarshalError().WithReaderContent(content)
+		return p, NewUnmarshalError(err).WithContent(content)
 	}
 
 	if p == *new(Profile) {

response.go

@@ -90,7 +90,7 @@ func checkFacebookError(r io.Reader) error {
 	decoder := json.NewDecoder(r)
 	err = decoder.Decode(&qr)
 	if err != nil {
-		return NewUnmarshalError().WithReader(decoder.Buffered())
+		return NewUnmarshalError(err).WithReader(decoder.Buffered())
 	}
 	if qr.Error != nil {
 		return xerrors.Errorf("facebook error: %w", qr.Error)
@@ -103,7 +103,7 @@ func getFacebookQueryResponse(r io.Reader) (QueryResponse, error) {
 	qr := QueryResponse{}
 	decoder := json.NewDecoder(r)
 	if err := decoder.Decode(&qr); err != nil {
-		return qr, NewUnmarshalError().WithReader(decoder.Buffered())
+		return qr, NewUnmarshalError(err).WithReader(decoder.Buffered())
 	}
 	if qr.Error != nil {
 		return qr, xerrors.Errorf("facebook error: %w", qr.Error)

unmarshal_error.go

@@ -1,43 +1,42 @@
 package messenger
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 )
 
 var ErrUnmarshal = errors.New("unmarshal error")
 
 type UnmarshalError struct {
-	Content io.Reader
+	Content   []byte
-	Err     error
+	ErrorText string
+	Err       error
 }
 
 func (u *UnmarshalError) Error() string {
-	content, err := ioutil.ReadAll(u.Content)
+	return fmt.Sprintf("can not unmarshal content: %s; error: %s", string(u.Content), u.ErrorText)
-	if err != nil {
-		content = []byte("[can not read content]")
-	}
-	return fmt.Sprintf("can not unmarshal content: %s", string(content))
 }
 
 func (u *UnmarshalError) Unwrap() error {
 	return u.Err
 }
 
-func NewUnmarshalError() *UnmarshalError {
+func NewUnmarshalError(err error) *UnmarshalError {
-	return &UnmarshalError{Err: ErrUnmarshal}
+	return &UnmarshalError{
+		Err:       ErrUnmarshal,
+		ErrorText: err.Error(),
+	}
 }
 
-func (u *UnmarshalError) WithReader(content io.Reader) *UnmarshalError {
+func (u *UnmarshalError) WithReader(reader io.Reader) *UnmarshalError {
+	content, _ := io.ReadAll(reader)
 	u.Content = content
 	return u
 }
 
-func (u *UnmarshalError) WithReaderContent(content []byte) *UnmarshalError {
+func (u *UnmarshalError) WithContent(content []byte) *UnmarshalError {
-	u.Content = bytes.NewReader(content)
+	u.Content = content
 	return u
 }
 

unmarshal_error_test.go

@@ -9,44 +9,49 @@ import (
 )
 
 func TestNewUnmarshalError(t *testing.T) {
-	err := NewUnmarshalError()
+	err := errors.New("some error")
-	assert.True(t, errors.Is(err, ErrUnmarshal))
+	unmarshalError := NewUnmarshalError(err)
+	assert.True(t, errors.Is(unmarshalError, ErrUnmarshal))
 }
 
 func TestUnmarshalError_Error(t *testing.T) {
+	err := errors.New("some error")
 	content := []byte("test content")
-	actual := NewUnmarshalError().WithReaderContent(content).Error()
+	actual := NewUnmarshalError(err).WithContent(content).Error()
-	expected := "can not unmarshal content: test content"
+	expected := "can not unmarshal content: test content; error: some error"
 	assert.Equal(t, expected, actual)
 }
 
 func TestUnmarshalError_Unwrap(t *testing.T) {
-	actual := NewUnmarshalError().Unwrap()
+	err := errors.New("some error")
+	actual := NewUnmarshalError(err).Unwrap()
 	expected := ErrUnmarshal
 	assert.Equal(t, expected, actual)
 }
 
-func TestUnmarshalError_WithReaderContent(t *testing.T) {
+func TestUnmarshalError_WithContent(t *testing.T) {
+	err := errors.New("some error")
 	content := []byte("test content")
-	reader := bytes.NewReader(content)
 
-	actual := NewUnmarshalError().WithReaderContent(content)
+	actual := NewUnmarshalError(err).WithContent(content)
-	expected := &UnmarshalError{Err: ErrUnmarshal, Content: reader}
+	expected := &UnmarshalError{Err: ErrUnmarshal, Content: content, ErrorText: err.Error()}
 	assert.Equal(t, expected, actual)
 }
 
 func TestUnmarshalError_WithReader(t *testing.T) {
+	err := errors.New("some error")
 	content := []byte("test content")
 	reader := bytes.NewReader(content)
 
-	actual := NewUnmarshalError().WithReader(reader)
+	actual := NewUnmarshalError(err).WithReader(reader)
-	expected := &UnmarshalError{Err: ErrUnmarshal, Content: reader}
+	expected := &UnmarshalError{Err: ErrUnmarshal, Content: content, ErrorText: err.Error()}
 	assert.Equal(t, expected, actual)
 }
 
 func TestUnmarshalError_WithErr(t *testing.T) {
-	err := errors.New("some error")
+	someError := errors.New("some error")
-	actual := NewUnmarshalError().WithErr(err)
+	otherError := errors.New("other error")
-	expected := &UnmarshalError{Err: err}
+	actual := NewUnmarshalError(someError).WithErr(otherError)
+	expected := &UnmarshalError{Err: otherError, ErrorText: someError.Error()}
 	assert.Equal(t, expected, actual)
 }