Merge pull request #4 from wneessen/writeto_interface

Rename Write() to WriteTo() so it satisfies the io.WriteTo interface

Author: Winni Neessen

client.go

@@ -359,7 +359,7 @@ func (c *Client) Send(ml ...*Msg) error {
 		if err != nil {
 			return fmt.Errorf("sending DATA command failed: %w", err)
 		}
-		_, err = m.Write(w)
+		_, err = m.WriteTo(w)
 		if err != nil {
 			return fmt.Errorf("sending mail content failed: %w", err)
 		}

doc.go

@@ -2,4 +2,4 @@
 package mail
 
 // VERSION is used in the default user agent string
-const VERSION = "0.1.8"
+const VERSION = "0.1.9"

msg.go

@@ -460,13 +460,18 @@ func (m *Msg) Reset() {
 	m.parts = nil
 }
 
-// Write writes the formated Msg into a give io.Writer
-func (m *Msg) Write(w io.Writer) (int64, error) {
+// WriteTo writes the formated Msg into a give io.Writer and satisfies the io.WriteTo interface
+func (m *Msg) WriteTo(w io.Writer) (int64, error) {
 	mw := &msgWriter{w: w, c: m.charset, en: m.encoder}
 	mw.writeMsg(m)
 	return mw.n, mw.err
 }
 
+// Write is an alias method to WriteTo due to compatiblity reasons
+func (m *Msg) Write(w io.Writer) (int64, error) {
+	return m.WriteTo(w)
+}
+
 // appendFile adds a File to the Msg (as attachment or embed)
 func (m *Msg) appendFile(c []*File, f *File, o ...FileOption) []*File {
 	// Override defaults with optionally provided FileOption functions
@@ -525,7 +530,7 @@ func (m *Msg) WriteToSendmailWithContext(ctx context.Context, sp string, a ...st
 	if err := ec.Start(); err != nil {
 		return fmt.Errorf("could not start sendmail execution: %w", err)
 	}
-	_, err = m.Write(si)
+	_, err = m.WriteTo(si)
 	if err != nil {
 		if !errors.Is(err, syscall.EPIPE) {
 			return fmt.Errorf("failed to write mail to buffer: %w", err)

msg_test.go

@@ -1123,22 +1123,37 @@ func TestMsg_hasMixed(t *testing.T) {
 	}
 }
 
+// TestMsg_WriteTo tests the WriteTo() method of the Msg
+func TestMsg_WriteTo(t *testing.T) {
+	m := NewMsg()
+	m.SetBodyString(TypeTextPlain, "Plain")
+	wbuf := bytes.Buffer{}
+	n, err := m.WriteTo(&wbuf)
+	if err != nil {
+		t.Errorf("WriteTo() failed: %s", err)
+		return
+	}
+	if n != int64(wbuf.Len()) {
+		t.Errorf("WriteTo() failed: expected written byte length: %d, got: %d", n, wbuf.Len())
+	}
+}
+
 // TestMsg_Write tests the Write() method of the Msg
 func TestMsg_Write(t *testing.T) {
 	m := NewMsg()
 	m.SetBodyString(TypeTextPlain, "Plain")
 	wbuf := bytes.Buffer{}
 	n, err := m.Write(&wbuf)
 	if err != nil {
-		t.Errorf("Write() failed: %s", err)
+		t.Errorf("WriteTo() failed: %s", err)
 		return
 	}
 	if n != int64(wbuf.Len()) {
-		t.Errorf("Write() failed: expected written byte length: %d, got: %d", n, wbuf.Len())
+		t.Errorf("WriteTo() failed: expected written byte length: %d, got: %d", n, wbuf.Len())
 	}
 }
 
-// TestMsg_WriteWithLongHeader tests the Write() method of the Msg with a long header
+// TestMsg_WriteWithLongHeader tests the WriteTo() method of the Msg with a long header
 func TestMsg_WriteWithLongHeader(t *testing.T) {
 	m := NewMsg()
 	m.SetBodyString(TypeTextPlain, "Plain")
@@ -1147,17 +1162,17 @@ func TestMsg_WriteWithLongHeader(t *testing.T) {
 	m.SetHeader(HeaderContentID, "XXXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXX",
 		"XXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXX")
 	wbuf := bytes.Buffer{}
-	n, err := m.Write(&wbuf)
+	n, err := m.WriteTo(&wbuf)
 	if err != nil {
-		t.Errorf("Write() failed: %s", err)
+		t.Errorf("WriteTo() failed: %s", err)
 		return
 	}
 	if n != int64(wbuf.Len()) {
-		t.Errorf("Write() failed: expected written byte length: %d, got: %d", n, wbuf.Len())
+		t.Errorf("WriteTo() failed: expected written byte length: %d, got: %d", n, wbuf.Len())
 	}
 }
 
-// TestMsg_WriteDiffEncoding tests the Write() method of the Msg with different Encoding
+// TestMsg_WriteDiffEncoding tests the WriteTo() method of the Msg with different Encoding
 func TestMsg_WriteDiffEncoding(t *testing.T) {
 	tests := []struct {
 		name string
@@ -1200,13 +1215,13 @@ func TestMsg_WriteDiffEncoding(t *testing.T) {
 				m.EmbedFile("README.md")
 			}
 			wbuf := bytes.Buffer{}
-			n, err := m.Write(&wbuf)
+			n, err := m.WriteTo(&wbuf)
 			if err != nil {
-				t.Errorf("Write() failed: %s", err)
+				t.Errorf("WriteTo() failed: %s", err)
 				return
 			}
 			if n != int64(wbuf.Len()) {
-				t.Errorf("Write() failed: expected written byte length: %d, got: %d", n, wbuf.Len())
+				t.Errorf("WriteTo() failed: expected written byte length: %d, got: %d", n, wbuf.Len())
 			}
 			wbuf.Reset()
 		})

msgwriter.go

@@ -279,7 +279,7 @@ func (mw *msgWriter) writeBody(f func(io.Writer) (int64, error), e Encoding) {
 	mw.err = ew.Close()
 	n, mw.err = io.Copy(w, &wbuf)
 
-	// Since the part writer uses the Write() method, we don't need to add the
+	// Since the part writer uses the WriteTo() method, we don't need to add the
 	// bytes twice
 	if mw.d == 0 {
 		mw.n += n

msgwriter_test.go

@@ -21,20 +21,20 @@ func (bw *brokenWriter) Write([]byte) (int, error) {
 	return 0, fmt.Errorf("intentionally failed")
 }
 
-// TestMsgWriter_Write tests the Write() method of the msgWriter
+// TestMsgWriter_Write tests the WriteTo() method of the msgWriter
 func TestMsgWriter_Write(t *testing.T) {
 	bw := &brokenWriter{}
 	mw := &msgWriter{w: bw, c: CharsetUTF8, en: mime.QEncoding}
 	_, err := mw.Write([]byte("test"))
 	if err == nil {
-		t.Errorf("msgWriter Write() with brokenWriter should fail, but didn't")
+		t.Errorf("msgWriter WriteTo() with brokenWriter should fail, but didn't")
 	}
 
 	// Also test the part when a previous error happened
 	mw.err = fmt.Errorf("broken")
 	_, err = mw.Write([]byte("test"))
 	if err == nil {
-		t.Errorf("msgWriter Write() with brokenWriter should fail, but didn't")
+		t.Errorf("msgWriter WriteTo() with brokenWriter should fail, but didn't")
 	}
 }