listmonk/messenger/emailer.go
2018-10-26 13:27:39 +05:30

94 lines
2.1 KiB
Go

package messenger
import (
"fmt"
"math/rand"
"net/smtp"
"time"
"github.com/jordan-wright/email"
)
const emName = "email"
// Server represents an SMTP server's credentials.
type Server struct {
Name string
Host string `mapstructure:"host"`
Port int `mapstructure:"port"`
AuthProtocol string `mapstructure:"auth_protocol"`
Username string `mapstructure:"username"`
Password string `mapstructure:"password"`
SendTimeout time.Duration `mapstructure:"send_timeout"`
MaxConns int `mapstructure:"max_conns"`
mailer *email.Pool
}
type emailer struct {
servers map[string]*Server
serverNames []string
numServers int
}
// NewEmailer creates and returns an e-mail Messenger backend.
// It takes multiple SMTP configurations.
func NewEmailer(srv ...Server) (Messenger, error) {
e := &emailer{
servers: make(map[string]*Server),
}
for _, s := range srv {
var auth smtp.Auth
if s.AuthProtocol == "cram" {
auth = smtp.CRAMMD5Auth(s.Username, s.Password)
} else {
auth = smtp.PlainAuth("", s.Username, s.Password, s.Host)
}
pool, err := email.NewPool(fmt.Sprintf("%s:%d", s.Host, s.Port), 4, auth)
if err != nil {
return nil, err
}
s.mailer = pool
e.servers[s.Name] = &s
e.serverNames = append(e.serverNames, s.Name)
}
e.numServers = len(e.serverNames)
return e, nil
}
// Name returns the Server's name.
func (e *emailer) Name() string {
return emName
}
// Push pushes a message to the server.
func (e *emailer) Push(fromAddr, toAddr, subject string, m []byte) error {
var key string
// If there are more than one SMTP servers, send to a random
// one from the list.
if e.numServers > 1 {
key = e.serverNames[rand.Intn(e.numServers)]
} else {
key = e.serverNames[0]
}
srv := e.servers[key]
err := srv.mailer.Send(&email.Email{
From: fromAddr,
To: []string{toAddr},
Subject: subject,
HTML: m,
}, srv.SendTimeout)
return err
}
// Flush flushes the message queue to the server.
func (e *emailer) Flush() error {
return nil
}