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|
package email
import (
"fmt"
"net"
"net/smtp"
"strings"
)
// Message creates a email to be sent
type Message struct {
To string
From string
Subject string
Body string
}
var (
ports = []int{25, 2525, 587}
)
// Send sends a message to recipient(s) listed in the 'To' field of a Message
func (m Message) Send() error {
if !strings.Contains(m.To, "@") {
return fmt.Errorf("Invalid recipient address: <%s>", m.To)
}
host := strings.Split(m.To, "@")[1]
addrs, err := net.LookupMX(host)
if err != nil {
return err
}
c, err := newClient(addrs, ports)
if err != nil {
return err
}
err = send(m, c)
if err != nil {
return err
}
return nil
}
func newClient(mx []*net.MX, ports []int) (*smtp.Client, error) {
for i := range mx {
for j := range ports {
server := strings.TrimSuffix(mx[i].Host, ".")
hostPort := fmt.Sprintf("%s:%d", server, ports[j])
client, err := smtp.Dial(hostPort)
if err != nil {
if j == len(ports)-1 {
return nil, err
}
continue
}
return client, nil
}
}
return nil, fmt.Errorf("Couldn't connect to servers %v on any common port.", mx)
}
func send(m Message, c *smtp.Client) error {
if err := c.Mail(m.From); err != nil {
return err
}
if err := c.Rcpt(m.To); err != nil {
return err
}
msg, err := c.Data()
if err != nil {
return err
}
if m.Subject != "" {
_, err = msg.Write([]byte("Subject: " + m.Subject + "\r\n"))
if err != nil {
return err
}
}
if m.From != "" {
_, err = msg.Write([]byte("From: <" + m.From + ">\r\n"))
if err != nil {
return err
}
}
if m.To != "" {
_, err = msg.Write([]byte("To: <" + m.To + ">\r\n"))
if err != nil {
return err
}
}
_, err = fmt.Fprint(msg, m.Body)
if err != nil {
return err
}
err = msg.Close()
if err != nil {
return err
}
err = c.Quit()
if err != nil {
return err
}
return nil
}
|
