package send
import (
"crypto/tls"
"fmt"
"io"
"net/url"
"strings"
"github.com/emersion/go-message/mail"
"github.com/emersion/go-smtp"
"github.com/pkg/errors"
)
func connectSmtp(starttls bool, host string, domain string) (*smtp.Client, error) {
serverName := host
if !strings.ContainsRune(host, ':') {
host += ":587" // Default to submission port
} else {
serverName = host[:strings.IndexRune(host, ':')]
}
var conn *smtp.Client
var err error
if starttls {
conn, err = smtp.DialStartTLS(host, &tls.Config{ServerName: serverName})
} else {
conn, err = smtp.Dial(host)
}
if err != nil {
return nil, errors.Wrap(err, "smtp.Dial")
}
if domain != "" {
err := conn.Hello(domain)
if err != nil {
conn.Close()
return nil, errors.Wrap(err, "Hello")
}
}
return conn, nil
}
func connectSmtps(host string, domain string) (*smtp.Client, error) {
serverName := host
if !strings.ContainsRune(host, ':') {
host += ":465" // Default to smtps port
} else {
serverName = host[:strings.IndexRune(host, ':')]
}
conn, err := smtp.DialTLS(host, &tls.Config{
ServerName: serverName,
})
if err != nil {
return nil, errors.Wrap(err, "smtp.DialTLS")
}
if domain != "" {
err := conn.Hello(domain)
if err != nil {
conn.Close()
return nil, errors.Wrap(err, "Hello")
}
}
return conn, nil
}
type smtpSender struct {
conn *smtp.Client
w io.WriteCloser
}
func (s *smtpSender) Write(p []byte) (int, error) {
return s.w.Write(p)
}
func (s *smtpSender) Close() error {
we := s.w.Close()
ce := s.conn.Close()
if we != nil {
return we
}
return ce
}
func newSmtpSender(
protocol string, auth string, uri *url.URL, domain string,
from *mail.Address, rcpts []*mail.Address,
) (io.WriteCloser, error) {
var err error
var conn *smtp.Client
switch protocol {
case "smtp":
conn, err = connectSmtp(true, uri.Host, domain)
case "smtp+insecure":
conn, err = connectSmtp(false, uri.Host, domain)
case "smtps":
conn, err = connectSmtps(uri.Host, domain)
default:
return nil, fmt.Errorf("not a smtp protocol %s", protocol)
}
if err != nil {
return nil, errors.Wrap(err, "Connection failed")
}
saslclient, err := newSaslClient(auth, uri)
if err != nil {
conn.Close()
return nil, err
}
if saslclient != nil {
if err := conn.Auth(saslclient); err != nil {
conn.Close()
return nil, errors.Wrap(err, "conn.Auth")
}
}
s := &smtpSender{
conn: conn,
}
if err := s.conn.Mail(from.Address, nil); err != nil {
conn.Close()
return nil, errors.Wrap(err, "conn.Mail")
}
for _, rcpt := range rcpts {
if err := s.conn.Rcpt(rcpt.Address, nil); err != nil {
conn.Close()
return nil, errors.Wrap(err, "conn.Rcpt")
}
}
s.w, err = s.conn.Data()
if err != nil {
conn.Close()
return nil, errors.Wrap(err, "conn.Data")
}
return s.w, nil
}
