Dialer.Dial() now automatically uses CRAM-MD5 when it's available

Also deprecated NewPlainDialer() in favor of NewDialer().

Fixes #52

README.md

@@ -60,7 +60,7 @@ bypass the verification of the server's certificate chain and host name by using
     )
 
     func main() {
-    	d := gomail.NewPlainDialer("smtp.example.com", 587, "user", "123456")
+    	d := gomail.NewDialer("smtp.example.com", 587, "user", "123456")
     	d.TLSConfig = &tls.Config{InsecureSkipVerify: true}
 
         // Send emails using d.

auth.go

@@ -7,51 +7,33 @@ import (
 	"net/smtp"
 )
 
-// plainAuth is an smtp.Auth that implements the PLAIN authentication mechanism.
-// It fallbacks to the LOGIN mechanism if it is the only mechanism advertised
-// by the server.
-type plainAuth struct {
+// loginAuth is an smtp.Auth that implements the LOGIN authentication mechanism.
+type loginAuth struct {
 	username string
 	password string
 	host     string
-	login    bool
 }
 
-func (a *plainAuth) Start(server *smtp.ServerInfo) (string, []byte, error) {
-	if server.Name != a.host {
-		return "", nil, errors.New("gomail: wrong host name")
-	}
-
-	var plain, login bool
-	for _, a := range server.Auth {
-		switch a {
-		case "PLAIN":
-			plain = true
-		case "LOGIN":
-			login = true
+func (a *loginAuth) Start(server *smtp.ServerInfo) (string, []byte, error) {
+	if !server.TLS {
+		advertised := false
+		for _, mechanism := range server.Auth {
+			if mechanism == "LOGIN" {
+				advertised = true
+				break
+			}
+		}
+		if !advertised {
+			return "", nil, errors.New("gomail: unencrypted connection")
 		}
 	}
-
-	if !server.TLS && !plain && !login {
-		return "", nil, errors.New("gomail: unencrypted connection")
-	}
-
-	if !plain && login {
-		a.login = true
-		return "LOGIN", nil, nil
+	if server.Name != a.host {
+		return "", nil, errors.New("gomail: wrong host name")
 	}
-
-	return "PLAIN", []byte("\x00" + a.username + "\x00" + a.password), nil
+	return "LOGIN", nil, nil
 }
 
-func (a *plainAuth) Next(fromServer []byte, more bool) ([]byte, error) {
-	if !a.login {
-		if more {
-			return nil, errors.New("gomail: unexpected server challenge")
-		}
-		return nil, nil
-	}
-
+func (a *loginAuth) Next(fromServer []byte, more bool) ([]byte, error) {
 	if !more {
 		return nil, nil
 	}

auth_test.go

@@ -11,103 +11,51 @@ const (
 	testHost = "smtp.example.com"
 )
 
-var testAuth = &plainAuth{
-	username: testUser,
-	password: testPwd,
-	host:     testHost,
-}
-
-type plainAuthTest struct {
+type authTest struct {
 	auths      []string
 	challenges []string
 	tls        bool
-	wantProto  string
 	wantData   []string
 	wantError  bool
 }
 
 func TestNoAdvertisement(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
-		auths:      []string{},
-		challenges: []string{"Username:", "Password:"},
-		tls:        false,
-		wantProto:  "PLAIN",
-		wantError:  true,
+	testLoginAuth(t, &authTest{
+		auths:     []string{},
+		tls:       false,
+		wantError: true,
 	})
 }
 
 func TestNoAdvertisementTLS(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
+	testLoginAuth(t, &authTest{
 		auths:      []string{},
 		challenges: []string{"Username:", "Password:"},
 		tls:        true,
-		wantProto:  "PLAIN",
-		wantData:   []string{"\x00" + testUser + "\x00" + testPwd},
-	})
-}
-
-func TestPlain(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
-		auths:      []string{"PLAIN"},
-		challenges: []string{"Username:", "Password:"},
-		tls:        false,
-		wantProto:  "PLAIN",
-		wantData:   []string{"\x00" + testUser + "\x00" + testPwd},
-	})
-}
-
-func TestPlainTLS(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
-		auths:      []string{"PLAIN"},
-		challenges: []string{"Username:", "Password:"},
-		tls:        true,
-		wantProto:  "PLAIN",
-		wantData:   []string{"\x00" + testUser + "\x00" + testPwd},
-	})
-}
-
-func TestPlainAndLogin(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
-		auths:      []string{"PLAIN", "LOGIN"},
-		challenges: []string{"Username:", "Password:"},
-		tls:        false,
-		wantProto:  "PLAIN",
-		wantData:   []string{"\x00" + testUser + "\x00" + testPwd},
-	})
-}
-
-func TestPlainAndLoginTLS(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
-		auths:      []string{"PLAIN", "LOGIN"},
-		challenges: []string{"Username:", "Password:"},
-		tls:        true,
-		wantProto:  "PLAIN",
-		wantData:   []string{"\x00" + testUser + "\x00" + testPwd},
+		wantData:   []string{"", testUser, testPwd},
 	})
 }
 
 func TestLogin(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
-		auths:      []string{"LOGIN"},
+	testLoginAuth(t, &authTest{
+		auths:      []string{"PLAIN", "LOGIN"},
 		challenges: []string{"Username:", "Password:"},
 		tls:        false,
-		wantProto:  "LOGIN",
 		wantData:   []string{"", testUser, testPwd},
 	})
 }
 
 func TestLoginTLS(t *testing.T) {
-	testPlainAuth(t, &plainAuthTest{
+	testLoginAuth(t, &authTest{
 		auths:      []string{"LOGIN"},
 		challenges: []string{"Username:", "Password:"},
 		tls:        true,
-		wantProto:  "LOGIN",
 		wantData:   []string{"", testUser, testPwd},
 	})
 }
 
-func testPlainAuth(t *testing.T, test *plainAuthTest) {
-	auth := &plainAuth{
+func testLoginAuth(t *testing.T, test *authTest) {
+	auth := &loginAuth{
 		username: testUser,
 		password: testPwd,
 		host:     testHost,
@@ -119,13 +67,13 @@ func testPlainAuth(t *testing.T, test *plainAuthTest) {
 	}
 	proto, toServer, err := auth.Start(server)
 	if err != nil && !test.wantError {
-		t.Fatalf("plainAuth.Start(): %v", err)
+		t.Fatalf("loginAuth.Start(): %v", err)
 	}
 	if err != nil && test.wantError {
 		return
 	}
-	if proto != test.wantProto {
-		t.Errorf("invalid protocol, got %q, want %q", proto, test.wantProto)
+	if proto != "LOGIN" {
+		t.Errorf("invalid protocol, got %q, want LOGIN", proto)
 	}
 
 	i := 0
@@ -134,10 +82,6 @@ func testPlainAuth(t *testing.T, test *plainAuthTest) {
 		t.Errorf("Invalid response, got %q, want %q", got, test.wantData[i])
 	}
 
-	if proto == "PLAIN" {
-		return
-	}
-
 	for _, challenge := range test.challenges {
 		i++
 		if i >= len(test.wantData) {
@@ -146,7 +90,7 @@ func testPlainAuth(t *testing.T, test *plainAuthTest) {
 
 		toServer, err = auth.Next([]byte(challenge), true)
 		if err != nil {
-			t.Fatalf("plainAuth.Auth(): %v", err)
+			t.Fatalf("loginAuth.Auth(): %v", err)
 		}
 		got = string(toServer)
 		if got != test.wantData[i] {

example_test.go

@@ -5,7 +5,6 @@ import (
 	"html/template"
 	"io"
 	"log"
-	"net/smtp"
 	"time"
 
 	"gopkg.in/gomail.v2"
@@ -20,7 +19,7 @@ func Example() {
 	m.SetBody("text/html", "Hello <b>Bob</b> and <i>Cora</i>!")
 	m.Attach("/home/Alex/lolcat.jpg")
 
-	d := gomail.NewPlainDialer("smtp.example.com", 587, "user", "123456")
+	d := gomail.NewDialer("smtp.example.com", 587, "user", "123456")
 
 	// Send the email to Bob, Cora and Dan.
 	if err := d.DialAndSend(m); err != nil {
@@ -33,7 +32,7 @@ func Example_daemon() {
 	ch := make(chan *gomail.Message)
 
 	go func() {
-		d := gomail.NewPlainDialer("smtp.example.com", 587, "user", "123456")
+		d := gomail.NewDialer("smtp.example.com", 587, "user", "123456")
 
 		var s gomail.SendCloser
 		var err error
@@ -80,7 +79,7 @@ func Example_newsletter() {
 		Address string
 	}
 
-	d := gomail.NewPlainDialer("smtp.example.com", 587, "user", "123456")
+	d := gomail.NewDialer("smtp.example.com", 587, "user", "123456")
 	s, err := d.Dial()
 	if err != nil {
 		panic(err)
@@ -114,24 +113,6 @@ func Example_noAuth() {
 	}
 }
 
-// Send an email using the CRAM-MD5 authentication mechanism.
-func Example_cRAMMD5() {
-	m := gomail.NewMessage()
-	m.SetHeader("From", "from@example.com")
-	m.SetHeader("To", "to@example.com")
-	m.SetHeader("Subject", "Hello!")
-	m.SetBody("text/plain", "Hello!")
-
-	d := gomail.Dialer{
-		Host: "localhost",
-		Port: 587,
-		Auth: smtp.CRAMMD5Auth("username", "secret"),
-	}
-	if err := d.DialAndSend(m); err != nil {
-		panic(err)
-	}
-}
-
 // Send an email using an API or postfix.
 func Example_noSMTP() {
 	m := gomail.NewMessage()