117 lines
2.5 KiB
Go
117 lines
2.5 KiB
Go
package smtp
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import (
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"crypto/tls"
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"errors"
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"fmt"
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"net"
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"net/mail"
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"net/smtp"
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)
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var (
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ErrSMTPInvalidConfig = errors.New("invalid smtp configuration")
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ErrSMTPConnectionFailed = errors.New("connection to smtp server failed")
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ErrSendMessageFailed = errors.New("could not send message")
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)
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type SSLSMTPConfig struct {
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URL string
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Username string
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Password string
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}
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func (ssc *SSLSMTPConfig) Valid() bool {
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if _, _, err := net.SplitHostPort(ssc.URL); err != nil {
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return false
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}
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return ssc.Username != "" && ssc.Password != ""
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}
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type SSLSMTP struct {
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config *SSLSMTPConfig
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client *smtp.Client
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connected bool
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}
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func NewSSLSMTP(config *SSLSMTPConfig) *SSLSMTP {
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return &SSLSMTP{
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config: config,
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}
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}
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func (s *SSLSMTP) Connect() error {
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if !s.config.Valid() {
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return ErrSMTPInvalidConfig
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}
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host, _, _ := net.SplitHostPort(s.config.URL)
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auth := smtp.PlainAuth("", s.config.Username, s.config.Password, host)
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conn, err := tls.Dial("tcp", s.config.URL, &tls.Config{ServerName: host})
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if err != nil {
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return fmt.Errorf("%w: %v", ErrSMTPConnectionFailed, err)
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}
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client, err := smtp.NewClient(conn, host)
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if err != nil {
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return fmt.Errorf("%w: %v", ErrSMTPConnectionFailed, err)
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}
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if err := client.Auth(auth); err != nil {
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return fmt.Errorf("%w: %v", ErrSMTPConnectionFailed, err)
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}
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s.client = client
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s.connected = true
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return nil
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}
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func (s *SSLSMTP) Close() error {
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if !s.connected {
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return nil
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}
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if err := s.client.Quit(); err != nil {
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return fmt.Errorf("%w: %v", ErrSMTPConnectionFailed, err)
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}
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s.connected = false
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return nil
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}
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func (s *SSLSMTP) Send(from, to mail.Address, subject, body string) error {
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if err := s.Connect(); err != nil {
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return err
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}
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defer s.Close()
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headers := make(map[string]string)
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headers["From"] = from.String()
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headers["To"] = to.String()
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headers["Subject"] = subject
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message := ""
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for k, v := range headers {
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message += fmt.Sprintf("%s: %s\r\n", k, v)
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}
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message += fmt.Sprintf("\r\n%s", body)
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if err := s.client.Mail(from.Address); err != nil {
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return fmt.Errorf("%w: %v", ErrSendMessageFailed, err)
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}
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if err := s.client.Rcpt(to.Address); err != nil {
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return fmt.Errorf("%w: %v", ErrSendMessageFailed, err)
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}
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wc, err := s.client.Data()
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if err != nil {
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return fmt.Errorf("%w: %v", ErrSendMessageFailed, err)
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}
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if _, err := wc.Write([]byte(message)); err != nil {
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return fmt.Errorf("%w: %v", ErrSendMessageFailed, err)
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}
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if err := wc.Close(); err != nil {
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return fmt.Errorf("%w: %v", ErrSendMessageFailed, err)
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}
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return nil
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}
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