mediocre-blog/srv/mailinglist/mailer.go

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package mailinglist
import (
"github.com/emersion/go-sasl"
"github.com/emersion/go-smtp"
)
// Mailer is used to deliver emails to arbitrary recipients.
type Mailer interface {
Send(to, subject, body string) error
}
// MailerParams are used to initialize a new Mailer instance
type MailerParams struct {
SMTPAddr string
// Optional, if not given then no auth is attempted.
SMTPAuth sasl.Client
// The sending email address to use for all emails being sent.
SendAs string
}
type mailer struct {
params MailerParams
}
// NewMailer initializes and returns a Mailer which will use an external SMTP
// server to deliver email.
func NewMailer(params MailerParams) Mailer {
return &mailer{
params: params,
}
}
func (m *mailer) Send(to, subject, body string) error {
msg := []byte("From: " + m.params.SendAs + "\r\n" +
"To: " + to + "\r\n" +
"Subject: " + subject + "\r\n\r\n" +
body + "\r\n")
c, err := smtp.Dial(m.params.SMTPAddr)
if err != nil {
return err
}
defer c.Close()
if err = c.Auth(m.params.SMTPAuth); err != nil {
return err
}
if err = c.Mail(m.params.SendAs, nil); err != nil {
return err
}
if err = c.Rcpt(to); err != nil {
return err
}
w, err := c.Data()
if err != nil {
return err
}
if _, err = w.Write(msg); err != nil {
return err
}
if err = w.Close(); err != nil {
return err
}
return c.Quit()
}