forked from getfider/fider
/
smtp.go
177 lines (158 loc) · 4.36 KB
/
smtp.go
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package smtp
import (
"crypto/rand"
"crypto/tls"
"encoding/hex"
"fmt"
"net"
gosmtp "net/smtp"
"net/url"
"strconv"
"time"
"github.com/getfider/fider/app/pkg/email"
"github.com/getfider/fider/app/pkg/errors"
"github.com/getfider/fider/app/pkg/log"
)
func authenticate(username string, password string, host string) gosmtp.Auth {
if username == "" && password == "" {
return nil
}
return AgnosticAuth("", username, password, host)
}
type builder struct {
content string
}
func (b *builder) Set(key, value string) {
b.content += fmt.Sprintf("%s: %s\r\n", key, value)
}
func (b *builder) Body(body string) {
b.content += "\r\n" + body
}
func (b *builder) Bytes() []byte {
return []byte(b.content)
}
//Sender is used to send emails
type Sender struct {
logger log.Logger
host string
port string
username string
password string
send func(string, string, gosmtp.Auth, string, []string, []byte) error
}
//NewSender creates a new mailgun email sender
func NewSender(logger log.Logger, host, port, username, password string) *Sender {
return &Sender{logger, host, port, username, password, sendMail}
}
//ReplaceSend can be used to mock internal send function
func (s *Sender) ReplaceSend(send func(string, string, gosmtp.Auth, string, []string, []byte) error) {
s.send = send
}
//Send an email
func (s *Sender) Send(ctx email.Context, templateName string, params email.Params, from string, to email.Recipient) error {
if to.Address == "" {
return nil
}
u, err := url.Parse(ctx.BaseURL())
localname := "localhost"
if err == nil {
localname = u.Hostname()
}
if !email.CanSendTo(to.Address) {
s.logger.Warnf("Skipping email to '@{Name} <@{Address}>'.", log.Props{
"Name": to.Name,
"Address": to.Address,
})
return nil
}
s.logger.Debugf("Sending email to @{Address} with template @{TemplateName} and params @{Params}.", log.Props{
"Address": to.Address,
"TemplateName": templateName,
"Params": to.Params,
})
message := email.RenderMessage(ctx, templateName, params.Merge(to.Params))
b := builder{}
b.Set("From", email.NewRecipient(from, email.NoReply, email.Params{}).String())
b.Set("Reply-To", email.NoReply)
b.Set("To", to.String())
b.Set("Subject", message.Subject)
b.Set("MIME-version", "1.0")
b.Set("Content-Type", "text/html; charset=\"UTF-8\"")
b.Set("Date", time.Now().Format(time.RFC1123Z))
b.Set("Message-ID", generateMessageID(localname))
b.Body(message.Body)
servername := fmt.Sprintf("%s:%s", s.host, s.port)
auth := authenticate(s.username, s.password, s.host)
err = s.send(localname, servername, auth, email.NoReply, []string{to.Address}, b.Bytes())
if err != nil {
return errors.Wrap(err, "failed to send email with template %s", templateName)
}
s.logger.Debug("Email sent.")
return nil
}
// BatchSend an email to multiple recipients
func (s *Sender) BatchSend(ctx email.Context, templateName string, params email.Params, from string, to []email.Recipient) error {
for _, r := range to {
if err := s.Send(ctx, templateName, params, from, r); err != nil {
return errors.Wrap(err, "failed to batch send email to %d recipients", len(to))
}
}
return nil
}
func sendMail(localName, serverAddress string, a gosmtp.Auth, from string, to []string, msg []byte) error {
host, _, _ := net.SplitHostPort(serverAddress)
c, err := gosmtp.Dial(serverAddress)
if err != nil {
return err
}
defer c.Close()
if err = c.Hello(localName); err != nil {
return err
}
if ok, _ := c.Extension("STARTTLS"); ok {
config := &tls.Config{ServerName: host}
if err = c.StartTLS(config); err != nil {
return err
}
}
if a != nil {
if ok, _ := c.Extension("AUTH"); !ok {
return errors.New("smtp: server doesn't support AUTH")
}
if err = c.Auth(a); err != nil {
return err
}
}
if err = c.Mail(from); err != nil {
return err
}
for _, addr := range to {
if err = c.Rcpt(addr); err != nil {
return err
}
}
w, err := c.Data()
if err != nil {
return err
}
_, err = w.Write(msg)
if err != nil {
return err
}
err = w.Close()
if err != nil {
return err
}
return c.Quit()
}
func generateMessageID(localName string) string {
timestamp := strconv.FormatInt(time.Now().UTC().UnixNano(), 10)
buf := make([]byte, 16)
_, err := rand.Read(buf)
if err != nil {
panic(err)
}
randStr := hex.EncodeToString(buf)
messageID := fmt.Sprintf("<%s.%s@%s>", randStr, timestamp, localName)
return messageID
}