/
mail.go
87 lines (72 loc) · 1.89 KB
/
mail.go
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package main
import (
"encoding/base64"
"fmt"
"net/mail"
"net/smtp"
"time"
)
type mailSender func(addr string, a smtp.Auth, from string, to []string, msg []byte) error
func sendEmail(senderFunc mailSender, smtpConfig smtpConfiguration, ts time.Time, errors []verificationError) error {
// set up possible authentication
var auth smtp.Auth
if smtpConfig.Auth != nil {
a := *smtpConfig.Auth
auth = smtp.PlainAuth(
"",
a.Username,
a.Password,
smtpConfig.Host,
)
} else {
auth = nil
}
from := mail.Address{Address: smtpConfig.From}
toString := makeToAddresses(smtpConfig.To)
title := "Ismonitor alert"
body := makeMessage(errors)
message := makeHeaders(from.String(), toString, title, ts) // headers
message += "\r\n"
message += base64.StdEncoding.EncodeToString([]byte(body)) // body
return senderFunc(
smtpConfig.Host+":"+fmt.Sprintf("%d", smtpConfig.Port),
auth,
from.Address,
smtpConfig.To,
[]byte(message))
}
func makeToAddresses(to []string) string {
var toString string
for i, t := range to {
ma := mail.Address{Address: t}
toString += ma.String()
if i != len(to)-1 {
// add comma between addresses unless it's the last one
toString += ", "
}
}
return toString
}
func makeHeaders(from string, to string, title string, ts time.Time) string {
const rfc2822 = "Mon, 02 Jan 2006 15:04:05 -0700"
header := make(map[string]string)
header["From"] = from
header["To"] = to
header["Subject"] = title
header["Date"] = ts.Format(rfc2822)
header["MIME-Version"] = "1.0"
header["Content-Type"] = "text/plain; charset=\"utf-8\""
header["Content-Transfer-Encoding"] = "base64"
message := ""
for k, v := range header {
message += fmt.Sprintf("%s: %s\r\n", k, v)
}
return message
}
func makeMessage(errors []verificationError) string {
body := ""
for _, e := range errors {
body += fmt.Sprintf("%s\n %s\n", e.title, e.message)
}
return body
}