Feature Request: io.Reader as attachment

message.go

@@ -311,6 +311,29 @@ func (m *Message) appendFile(list []*file, name string, settings []FileSetting)
 	return append(list, f)
 }
 
+func (m *Message) appendStream(list []*file, fileName string, src io.Reader, settings []FileSetting) []*file {
+	f := &file{
+		Name:   filepath.Base(fileName),
+		Header: make(map[string][]string),
+		CopyFunc: func(w io.Writer) error {
+			if _, err := io.Copy(w, src); err != nil {
+				return err
+			}
+			return nil
+		},
+	}
+
+	for _, s := range settings {
+		s(f)
+	}
+
+	if list == nil {
+		return []*file{f}
+	}
+
+	return append(list, f)
+}
+
 // Attach attaches the files to the email.
 func (m *Message) Attach(filename string, settings ...FileSetting) {
 	m.attachments = m.appendFile(m.attachments, filename, settings)
@@ -320,3 +343,13 @@ func (m *Message) Attach(filename string, settings ...FileSetting) {
 func (m *Message) Embed(filename string, settings ...FileSetting) {
 	m.embedded = m.appendFile(m.embedded, filename, settings)
 }
+
+// Attach file to a message from a io.Reader object
+func (m *Message) AttachStream(src io.Reader, fileName string, settings ...FileSetting) {
+	m.attachments = m.appendStream(m.attachments, fileName, src, settings)
+}
+
+// Embed file to a message from a io.Reader object
+func (m *Message) EmbedStream(src io.Reader, fileName string, settings ...FileSetting) {
+	m.embedded = m.appendStream(m.embedded, fileName, src, settings)
+}

message_stream_attach_test.go

@@ -0,0 +1,93 @@
+package gomail
+
+import (
+	"bytes"
+	"encoding/base64"
+	"io"
+	"path/filepath"
+	"testing"
+)
+
+func mockCopyStream(name string) (io.Reader, string, FileSetting) {
+	nm := filepath.Base(name)
+	b := bytes.NewReader([]byte("Content of " + nm))
+	return b, nm, func(f *file) {}
+}
+func mockCopyStreamWithHeader(m *Message, name string, h map[string][]string) (io.Reader, string, FileSetting) {
+	rdr, nm, _ := mockCopyStream(name)
+	return rdr, nm, SetHeader(h)
+}
+
+func TestStreamAttachmentsOnly(t *testing.T) {
+	m := NewMessage()
+	m.SetHeader("From", "[email protected]")
+	m.SetHeader("To", "[email protected]")
+	m.AttachStream(mockCopyStream("/tmp/test.pdf"))
+	m.AttachStream(mockCopyStream("/tmp/test.zip"))
+
+	want := &message{
+		from: "[email protected]",
+		to:   []string{"[email protected]"},
+		content: "From: [email protected]\r\n" +
+			"To: [email protected]\r\n" +
+			"Content-Type: multipart/mixed;\r\n" +
+			" boundary=_BOUNDARY_1_\r\n" +
+			"\r\n" +
+			"--_BOUNDARY_1_\r\n" +
+			"Content-Type: application/pdf; name=\"test.pdf\"\r\n" +
+			"Content-Disposition: attachment; filename=\"test.pdf\"\r\n" +
+			"Content-Transfer-Encoding: base64\r\n" +
+			"\r\n" +
+			base64.StdEncoding.EncodeToString([]byte("Content of test.pdf")) + "\r\n" +
+			"--_BOUNDARY_1_\r\n" +
+			"Content-Type: application/zip; name=\"test.zip\"\r\n" +
+			"Content-Disposition: attachment; filename=\"test.zip\"\r\n" +
+			"Content-Transfer-Encoding: base64\r\n" +
+			"\r\n" +
+			base64.StdEncoding.EncodeToString([]byte("Content of test.zip")) + "\r\n" +
+			"--_BOUNDARY_1_--\r\n",
+	}
+
+	testMessage(t, m, 1, want)
+}
+
+func TestStreamEmbedded(t *testing.T) {
+	m := NewMessage()
+	m.SetHeader("From", "[email protected]")
+	m.SetHeader("To", "[email protected]")
+	m.EmbedStream(mockCopyStreamWithHeader(m, "image1.jpg", map[string][]string{"Content-ID": {"<test-content-id>"}}))
+	m.EmbedStream(mockCopyStream("image2.jpg"))
+	m.SetBody("text/plain", "Test")
+
+	want := &message{
+		from: "[email protected]",
+		to:   []string{"[email protected]"},
+		content: "From: [email protected]\r\n" +
+			"To: [email protected]\r\n" +
+			"Content-Type: multipart/related;\r\n" +
+			" boundary=_BOUNDARY_1_\r\n" +
+			"\r\n" +
+			"--_BOUNDARY_1_\r\n" +
+			"Content-Type: text/plain; charset=UTF-8\r\n" +
+			"Content-Transfer-Encoding: quoted-printable\r\n" +
+			"\r\n" +
+			"Test\r\n" +
+			"--_BOUNDARY_1_\r\n" +
+			"Content-Type: image/jpeg; name=\"image1.jpg\"\r\n" +
+			"Content-Disposition: inline; filename=\"image1.jpg\"\r\n" +
+			"Content-ID: <test-content-id>\r\n" +
+			"Content-Transfer-Encoding: base64\r\n" +
+			"\r\n" +
+			base64.StdEncoding.EncodeToString([]byte("Content of image1.jpg")) + "\r\n" +
+			"--_BOUNDARY_1_\r\n" +
+			"Content-Type: image/jpeg; name=\"image2.jpg\"\r\n" +
+			"Content-Disposition: inline; filename=\"image2.jpg\"\r\n" +
+			"Content-ID: <image2.jpg>\r\n" +
+			"Content-Transfer-Encoding: base64\r\n" +
+			"\r\n" +
+			base64.StdEncoding.EncodeToString([]byte("Content of image2.jpg")) + "\r\n" +
+			"--_BOUNDARY_1_--\r\n",
+	}
+
+	testMessage(t, m, 1, want)
+}