Refactored file management

CHANGELOG.md

@@ -4,9 +4,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [2.0.0] - unreleased
 - Mailer has been removed. It has been replaced by Dialer and Sender.
-- `CreateFile` has been removed and `OpenFile` has been renamed into `NewFile`.
+- `File` type and the `CreateFile` and `OpenFile` functions have been removed.
-- `File` fields changed. The `File.Header` field replaces `File.MimeType`
+- `Message.Attach` and `Message.Embed` have a new signature.
-and `File.ContentID`.
 - `Message.GetBodyWriter` has been removed. Use `Message.AddAlternativeWriter`
 instead.
 - `Message.Export` has been removed. `Message.WriteTo` can be used instead.

example_test.go

@@ -15,7 +15,7 @@ func Example() {
 	m.SetAddressHeader("Cc", "dan@example.com", "Dan")
 	m.SetHeader("Subject", "Hello!")
 	m.SetBody("text/html", "Hello <b>Bob</b> and <i>Cora</i>!")
-	m.Attach(gomail.NewFile("/home/Alex/lolcat.jpg"))
+	m.Attach("/home/Alex/lolcat.jpg")
 
 	d := gomail.NewPlainDialer("smtp.example.com", "user", "123456", 587)
 

message.go

@@ -12,8 +12,8 @@ import (
 type Message struct {
 	header      header
 	parts       []part
-	attachments []*File
+	attachments []*file
-	embedded    []*File
+	embedded    []*file
 	charset     string
 	encoding    Encoding
 	hEncoder    mimeEncoder
@@ -106,12 +106,20 @@ const (
 
 // SetHeader sets a value to the given header field.
 func (m *Message) SetHeader(field string, value ...string) {
-	for i := range value {
+	m.encodeHeader(value)
-		value[i] = m.encodeHeader(value[i])
-	}
 	m.header[field] = value
 }
 
+func (m *Message) encodeHeader(values []string) {
+	for i := range values {
+		values[i] = m.encodeString(values[i])
+	}
+}
+
+func (m *Message) encodeString(value string) string {
+	return m.hEncoder.Encode(m.charset, value)
+}
+
 // SetHeaders sets the message headers.
 //
 // Example:
@@ -134,7 +142,7 @@ func (m *Message) SetAddressHeader(field, address, name string) {
 
 // FormatAddress formats an address and a name as a valid RFC 5322 address.
 func (m *Message) FormatAddress(address, name string) string {
-	enc := m.encodeHeader(name)
+	enc := m.encodeString(name)
 	if enc == name {
 		m.buf.WriteByte('"')
 		for i := 0; i < len(name); i++ {
@@ -170,10 +178,6 @@ func hasSpecials(text string) bool {
 	return false
 }
 
-func (m *Message) encodeHeader(value string) string {
-	return m.hEncoder.Encode(m.charset, value)
-}
-
 // SetDateHeader sets a date to the given header field.
 func (m *Message) SetDateHeader(field string, date time.Time) {
 	m.header[field] = []string{m.FormatDate(date)}
@@ -254,27 +258,61 @@ func (m *Message) getPartHeader(contentType string) header {
 	}
 }
 
-// A File represents a file that can be attached or embedded in an email.
+type file struct {
-type File struct {
-	// Name represents the base name of the file. If the file is attached to the
-	// message it is the name of the attachment.
 	Name     string
-	// Header represents the MIME header of the message part that contains the
-	// file content. It is empty by default. Mandatory headers are automatically
-	// added if they are not sent when sending the email.
 	Header   map[string][]string
-	// Copier is a function run when the message is sent. It should copy the
+	CopyFunc func(w io.Writer) error
-	// content of the file to w.
-	Copier func(w io.Writer) error
 }
 
-// NewFile creates a File from the given filename.
+func (f *file) setHeader(field, value string) {
-func NewFile(filename string) *File {
+	f.Header[field] = []string{value}
-	return &File{
+}
-		Name:   filepath.Base(filename),
+
+// A FileSetting can be used as an argument in Message.Attach or Message.Embed.
+type FileSetting func(*file)
+
+// SetHeader is a file setting to set the MIME header of the message part that
+// contains the file content.
+//
+// Mandatory headers are automatically added if they are not set when sending
+// the email.
+//
+// Example:
+//
+// 	h := map[string][]string{"Content-ID": {"<foo@bar.mail>"}}
+//	m.Attach("foo.jpg", gomail.SetHeader(h))
+func SetHeader(h map[string][]string) FileSetting {
+	return func(f *file) {
+		for k, v := range h {
+			f.Header[k] = v
+		}
+	}
+}
+
+// SetCopyFunc is a file setting to replace the function that runs when the
+// message is sent.
+// It should copy the content of the file to the io.Writer.
+// The default copy function opens the file with the given filename, and copy
+// its content to the io.Writer.
+//
+// Example:
+//
+//	m.Attach("foo.txt", gomail.SetCopyFunc(func(w io.Writer) error {
+// 		_, err := w.Write([]byte("Content of foo.txt"))
+// 		return err
+// 	}))
+func SetCopyFunc(f func(io.Writer) error) FileSetting {
+	return func(fi *file) {
+		fi.CopyFunc = f
+	}
+}
+
+func (m *Message) appendFile(list []*file, name string, settings []FileSetting) []*file {
+	f := &file{
+		Name:   filepath.Base(name),
 		Header: make(map[string][]string),
-		Copier: func(w io.Writer) error {
+		CopyFunc: func(w io.Writer) error {
-			h, err := os.Open(filename)
+			h, err := os.Open(name)
 			if err != nil {
 				return err
 			}
@@ -285,35 +323,33 @@ func NewFile(filename string) *File {
 			return h.Close()
 		},
 	}
+
+	for _, s := range settings {
+		s(f)
 	}
 
-func (f *File) setHeader(field string, value ...string) {
+	if list == nil {
-	f.Header[field] = value
+		return []*file{f}
+	}
+
+	return append(list, f)
 }
 
 // Attach attaches the files to the email.
 //
 // Example:
 //
-//	m.Attach(gomail.NewFile("/tmp/image.jpg"))
+//	m.Attach("/tmp/image.jpg")
-func (m *Message) Attach(f ...*File) {
+func (m *Message) Attach(filename string, settings ...FileSetting) {
-	if m.attachments == nil {
+	m.attachments = m.appendFile(m.attachments, filename, settings)
-		m.attachments = f
-	} else {
-		m.attachments = append(m.attachments, f...)
-	}
 }
 
 // Embed embeds the images to the email.
 //
 // Example:
 //
-//	m.Embed(gomail.NewFile("/tmp/image.jpg"))
+//	m.Embed("/tmp/image.jpg")
 //	m.SetBody("text/html", `<img src="cid:image.jpg" alt="My image" />`)
-func (m *Message) Embed(image ...*File) {
+func (m *Message) Embed(filename string, settings ...FileSetting) {
-	if m.embedded == nil {
+	m.embedded = m.appendFile(m.embedded, filename, settings)
-		m.embedded = image
-	} else {
-		m.embedded = append(m.embedded, image...)
-	}
 }

message_test.go

@@ -195,7 +195,7 @@ func TestAttachmentOnly(t *testing.T) {
 	m := NewMessage()
 	m.SetHeader("From", "from@example.com")
 	m.SetHeader("To", "to@example.com")
-	m.Attach(testFile("/tmp/test.pdf"))
+	m.Attach(mockCopyFile("/tmp/test.pdf"))
 
 	want := &message{
 		from: "from@example.com",
@@ -217,7 +217,7 @@ func TestAttachment(t *testing.T) {
 	m.SetHeader("From", "from@example.com")
 	m.SetHeader("To", "to@example.com")
 	m.SetBody("text/plain", "Test")
-	m.Attach(testFile("/tmp/test.pdf"))
+	m.Attach(mockCopyFile("/tmp/test.pdf"))
 
 	want := &message{
 		from: "from@example.com",
@@ -247,8 +247,8 @@ func TestAttachmentsOnly(t *testing.T) {
 	m := NewMessage()
 	m.SetHeader("From", "from@example.com")
 	m.SetHeader("To", "to@example.com")
-	m.Attach(testFile("/tmp/test.pdf"))
+	m.Attach(mockCopyFile("/tmp/test.pdf"))
-	m.Attach(testFile("/tmp/test.zip"))
+	m.Attach(mockCopyFile("/tmp/test.zip"))
 
 	want := &message{
 		from: "from@example.com",
@@ -280,8 +280,8 @@ func TestAttachments(t *testing.T) {
 	m.SetHeader("From", "from@example.com")
 	m.SetHeader("To", "to@example.com")
 	m.SetBody("text/plain", "Test")
-	m.Attach(testFile("/tmp/test.pdf"))
+	m.Attach(mockCopyFile("/tmp/test.pdf"))
-	m.Attach(testFile("/tmp/test.zip"))
+	m.Attach(mockCopyFile("/tmp/test.zip"))
 
 	want := &message{
 		from: "from@example.com",
@@ -317,10 +317,8 @@ func TestEmbedded(t *testing.T) {
 	m := NewMessage()
 	m.SetHeader("From", "from@example.com")
 	m.SetHeader("To", "to@example.com")
-	f := testFile("image1.jpg")
+	m.Embed(mockCopyFileWithHeader(m, "image1.jpg", map[string][]string{"Content-ID": {"<test-content-id>"}}))
-	f.Header["Content-ID"] = []string{"<test-content-id>"}
+	m.Embed(mockCopyFile("image2.jpg"))
-	m.Embed(f)
-	m.Embed(testFile("image2.jpg"))
 	m.SetBody("text/plain", "Test")
 
 	want := &message{
@@ -361,8 +359,8 @@ func TestFullMessage(t *testing.T) {
 	m.SetHeader("To", "to@example.com")
 	m.SetBody("text/plain", "¡Hola, señor!")
 	m.AddAlternative("text/html", "¡<b>Hola</b>, <i>señor</i>!</h1>")
-	m.Attach(testFile("test.pdf"))
+	m.Attach(mockCopyFile("test.pdf"))
-	m.Embed(testFile("image.jpg"))
+	m.Embed(mockCopyFile("image.jpg"))
 
 	want := &message{
 		from: "from@example.com",
@@ -591,13 +589,16 @@ func getBoundaries(t *testing.T, count int, m string) []string {
 
 var boundaryRegExp = regexp.MustCompile("boundary=(\\w+)")
 
-func testFile(name string) *File {
+func mockCopyFile(name string) (string, FileSetting) {
-	f := NewFile(name)
+	return name, SetCopyFunc(func(w io.Writer) error {
-	f.Copier = func(w io.Writer) error {
+		_, err := w.Write([]byte("Content of " + filepath.Base(name)))
-		_, err := w.Write([]byte("Content of " + filepath.Base(f.Name)))
 		return err
+	})
 }
-	return f
+
+func mockCopyFileWithHeader(m *Message, name string, h map[string][]string) (string, FileSetting, FileSetting) {
+	name, f := mockCopyFile(name)
+	return name, f, SetHeader(h)
 }
 
 func BenchmarkFull(b *testing.B) {
@@ -618,8 +619,8 @@ func BenchmarkFull(b *testing.B) {
 		})
 		m.SetBody("text/plain", "¡Hola, señor!")
 		m.AddAlternative("text/html", "<p>¡Hola, señor!</p>")
-		m.Attach(testFile("benchmark.txt"))
+		m.Attach(mockCopyFile("benchmark.txt"))
-		m.Embed(testFile("benchmark.jpg"))
+		m.Embed(mockCopyFile("benchmark.jpg"))
 
 		if err := Send(discardFunc, m); err != nil {
 			panic(err)

writeto.go

@@ -104,7 +104,7 @@ func (w *messageWriter) closeMultipart() {
 	}
 }
 
-func (w *messageWriter) addFiles(files []*File, isAttachment bool) {
+func (w *messageWriter) addFiles(files []*file, isAttachment bool) {
 	for _, f := range files {
 		if _, ok := f.Header["Content-Type"]; !ok {
 			mediaType := mime.TypeByExtension(filepath.Ext(f.Name))
@@ -134,7 +134,7 @@ func (w *messageWriter) addFiles(files []*File, isAttachment bool) {
 			}
 		}
 		w.writeHeaders(f.Header)
-		w.writeBody(f.Copier, Base64)
+		w.writeBody(f.CopyFunc, Base64)
 	}
 }