Merge pull request #104 from wneessen/refactor_dsn_to_smtp

Refactor DSN handling from client.go to smtp.go

client.go

@@ -633,91 +633,3 @@ func (c *Client) auth() error {
 	}
 	return nil
 }
-
-// mail is an extension to the Go std library mail method. It decideds wether to call the
-// original mail method from the std library or in case DSN is enabled on the Client to
-// call our own method instead
-func (c *Client) mail(f string) error {
-	ok, _ := c.sc.Extension("DSN")
-	if ok && c.dsn {
-		return c.dsnMail(f)
-	}
-	return c.sc.Mail(f)
-}
-
-// rcpt is an extension to the Go std library rcpt method. It decideds wether to call
-// original rcpt method from the std library or in case DSN is enabled on the Client to
-// call our own method instead
-func (c *Client) rcpt(t string) error {
-	ok, _ := c.sc.Extension("DSN")
-	if ok && c.dsn {
-		return c.dsnRcpt(t)
-	}
-	return c.sc.Rcpt(t)
-}
-
-// dsnRcpt issues a RCPT command to the server using the provided email address.
-// A call to rcpt must be preceded by a call to mail and may be followed by
-// a Data call or another rcpt call.
-//
-// This is a copy of the original Go std library net/smtp function with additions
-// for the DSN extension
-func (c *Client) dsnRcpt(t string) error {
-	if err := validateLine(t); err != nil {
-		return err
-	}
-	if len(c.dsnrntype) <= 0 {
-		return c.sc.Rcpt(t)
-	}
-
-	rno := strings.Join(c.dsnrntype, ",")
-	_, _, err := c.cmd(25, "RCPT TO:<%s> NOTIFY=%s", t, rno)
-	return err
-}
-
-// dsnMail issues a MAIL command to the server using the provided email address.
-// If the server supports the 8BITMIME extension, mail adds the BODY=8BITMIME
-// parameter. If the server supports the SMTPUTF8 extension, mail adds the
-// SMTPUTF8 parameter.
-// This initiates a mail transaction and is followed by one or more rcpt calls.
-//
-// This is a copy of the original Go std library net/smtp function with additions
-// for the DSN extension
-func (c *Client) dsnMail(f string) error {
-	if err := validateLine(f); err != nil {
-		return err
-	}
-	cmdStr := "MAIL FROM:<%s>"
-	if ok, _ := c.sc.Extension("8BITMIME"); ok {
-		cmdStr += " BODY=8BITMIME"
-	}
-	if ok, _ := c.sc.Extension("SMTPUTF8"); ok {
-		cmdStr += " SMTPUTF8"
-	}
-	cmdStr += fmt.Sprintf(" RET=%s", c.dsnmrtype)
-
-	_, _, err := c.cmd(250, cmdStr, f)
-	return err
-}
-
-// validateLine checks to see if a line has CR or LF as per RFC 5321
-// This is a 1:1 copy of the method from the original Go std library net/smtp
-func validateLine(line string) error {
-	if strings.ContainsAny(line, "\n\r") {
-		return errors.New("smtp: A line must not contain CR or LF")
-	}
-	return nil
-}
-
-// cmd is a convenience function that sends a command and returns the response
-// This is a 1:1 copy of the method from the original Go std library net/smtp
-func (c *Client) cmd(expectCode int, format string, args ...interface{}) (int, string, error) {
-	id, err := c.sc.Text.Cmd(format, args...)
-	if err != nil {
-		return 0, "", err
-	}
-	c.sc.Text.StartResponse(id)
-	defer c.sc.Text.EndResponse(id)
-	code, msg, err := c.sc.Text.ReadResponse(expectCode)
-	return code, msg, err
-}

client_119.go

@@ -7,6 +7,8 @@
 
 package mail
 
+import "strings"
+
 // Send sends out the mail message
 func (c *Client) Send(ml ...*Msg) error {
 	if cerr := c.checkConn(); cerr != nil {
@@ -38,7 +40,12 @@ func (c *Client) Send(ml ...*Msg) error {
 			continue
 		}
 
-		if err := c.mail(f); err != nil {
+		if c.dsn {
+			if c.dsnmrtype != "" {
+				c.sc.SetDSNMailReturnOption(string(c.dsnmrtype))
+			}
+		}
+		if err := c.sc.Mail(f); err != nil {
 			se := &SendError{Reason: ErrSMTPMailFrom, errlist: []error{err}, isTemp: isTempError(err)}
 			if reserr := c.sc.Reset(); reserr != nil {
 				se.errlist = append(se.errlist, reserr)
@@ -51,8 +58,10 @@ func (c *Client) Send(ml ...*Msg) error {
 		rse := &SendError{}
 		rse.errlist = make([]error, 0)
 		rse.rcpt = make([]string, 0)
+		rno := strings.Join(c.dsnrntype, ",")
+		c.sc.SetDSNRcptNotifyOption(rno)
 		for _, r := range rl {
-			if err := c.rcpt(r); err != nil {
+			if err := c.sc.Rcpt(r); err != nil {
 				rse.Reason = ErrSMTPRcptTo
 				rse.errlist = append(rse.errlist, err)
 				rse.rcpt = append(rse.rcpt, r)

client_120.go

@@ -9,6 +9,7 @@ package mail
 
 import (
 	"errors"
+	"strings"
 )
 
 // Send sends out the mail message
@@ -39,7 +40,12 @@ func (c *Client) Send(ml ...*Msg) (rerr error) {
 			continue
 		}
 
-		if err := c.mail(f); err != nil {
+		if c.dsn {
+			if c.dsnmrtype != "" {
+				c.sc.SetDSNMailReturnOption(string(c.dsnmrtype))
+			}
+		}
+		if err := c.sc.Mail(f); err != nil {
 			m.sendError = &SendError{Reason: ErrSMTPMailFrom, errlist: []error{err}, isTemp: isTempError(err)}
 			rerr = errors.Join(rerr, m.sendError)
 			if reserr := c.sc.Reset(); reserr != nil {
@@ -51,8 +57,10 @@ func (c *Client) Send(ml ...*Msg) (rerr error) {
 		rse := &SendError{}
 		rse.errlist = make([]error, 0)
 		rse.rcpt = make([]string, 0)
+		rno := strings.Join(c.dsnrntype, ",")
+		c.sc.SetDSNRcptNotifyOption(rno)
 		for _, r := range rl {
-			if err := c.rcpt(r); err != nil {
+			if err := c.sc.Rcpt(r); err != nil {
 				rse.Reason = ErrSMTPRcptTo
 				rse.errlist = append(rse.errlist, err)
 				rse.rcpt = append(rse.rcpt, r)

client_test.go

@@ -994,27 +994,6 @@ func TestClient_auth(t *testing.T) {
 	}
 }
 
-// TestValidateLine tests the validateLine() method
-func TestValidateLine(t *testing.T) {
-	tests := []struct {
-		name  string
-		value string
-		sf    bool
-	}{
-		{"valid line", "valid line", false},
-		{`invalid line: \n`, "invalid line\n", true},
-		{`invalid line: \r`, "invalid line\r", true},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if err := validateLine(tt.value); err != nil && !tt.sf {
-				t.Errorf("validateLine failed: %s", err)
-			}
-		})
-	}
-}
-
 // TestClient_Send_MsgSendError tests the Client.Send method with a broken recipient and verifies
 // that the SendError type works properly
 func TestClient_Send_MsgSendError(t *testing.T) {

smtp/smtp.go

@@ -17,6 +17,7 @@
 //	8BITMIME  RFC 1652
 //	AUTH      RFC 2554
 //	STARTTLS  RFC 3207
+//	DSN       RFC 1891
 package smtp
 
 import (
@@ -50,9 +51,12 @@ type Client struct {
 	localName  string // the name to use in HELO/EHLO
 	didHello   bool   // whether we've said HELO/EHLO
 	helloError error  // the error from the hello
-
+	// debug logging
 	debug  bool        // debug logging is enabled
 	logger *log.Logger // logger will be used for debug logging
+	// DSN support
+	dsnmrtype string // dsnmrtype defines the mail return option in case DSN is enabled
+	dsnrntype string // dsnrntype defines the recipient notify option in case DSN is enabled
 }
 
 // logDirection is a type wrapper for the direction a debug log message goes
@@ -256,6 +260,10 @@ func (c *Client) Mail(from string) error {
 		if _, ok := c.ext["SMTPUTF8"]; ok {
 			cmdStr += " SMTPUTF8"
 		}
+		_, ok := c.ext["DSN"]
+		if ok && c.dsnmrtype != "" {
+			cmdStr += fmt.Sprintf(" RET=%s", c.dsnmrtype)
+		}
 	}
 	_, _, err := c.cmd(250, cmdStr, from)
 	return err
@@ -268,6 +276,11 @@ func (c *Client) Rcpt(to string) error {
 	if err := validateLine(to); err != nil {
 		return err
 	}
+	_, ok := c.ext["DSN"]
+	if ok && c.dsnrntype != "" {
+		_, _, err := c.cmd(25, "RCPT TO:<%s> NOTIFY=%s", to, c.dsnrntype)
+		return err
+	}
 	_, _, err := c.cmd(25, "RCPT TO:<%s>", to)
 	return err
 }
@@ -434,6 +447,16 @@ func (c *Client) SetDebugLog(v bool) {
 	c.logger = nil
 }
 
+// SetDSNMailReturnOption sets the DSN mail return option for the Mail method
+func (c *Client) SetDSNMailReturnOption(d string) {
+	c.dsnmrtype = d
+}
+
+// SetDSNRcptNotifyOption sets the DSN recipient notify option for the Mail method
+func (c *Client) SetDSNRcptNotifyOption(d string) {
+	c.dsnrntype = d
+}
+
 // debugLog checks if the debug flag is set and if so logs the provided message to StdErr
 func (c *Client) debugLog(d logDirection, f string, a ...interface{}) {
 	if c.debug {