package alpsbase import ( "bufio" "bytes" "fmt" "io" "io/ioutil" "mime" "mime/multipart" "strings" "time" "github.com/emersion/go-message/mail" "github.com/emersion/go-smtp" ) func quote(r io.Reader) (string, error) { scanner := bufio.NewScanner(r) var builder strings.Builder for scanner.Scan() { builder.WriteString("> ") builder.Write(scanner.Bytes()) builder.WriteString("\n") } if err := scanner.Err(); err != nil { return "", fmt.Errorf("quote: failed to read original message: %s", err) } return builder.String(), nil } type Attachment interface { MIMEType() string Filename() string Open() (io.ReadCloser, error) } type formAttachment struct { *multipart.FileHeader } func (att *formAttachment) Open() (io.ReadCloser, error) { return att.FileHeader.Open() } func (att *formAttachment) MIMEType() string { // TODO: retain params, e.g. "charset"? t, _, _ := mime.ParseMediaType(att.FileHeader.Header.Get("Content-Type")) return t } func (att *formAttachment) Filename() string { return att.FileHeader.Filename } type imapAttachment struct { Mailbox string Uid uint32 Node *IMAPPartNode Body []byte } func (att *imapAttachment) Open() (io.ReadCloser, error) { if att.Body == nil { return nil, fmt.Errorf("IMAP attachment has not been pre-fetched") } return ioutil.NopCloser(bytes.NewReader(att.Body)), nil } func (att *imapAttachment) MIMEType() string { return att.Node.MIMEType } func (att *imapAttachment) Filename() string { return att.Node.Filename } type OutgoingMessage struct { From string To []string Subject string MessageID string InReplyTo string Text string Attachments []Attachment } func (msg *OutgoingMessage) ToString() string { return strings.Join(msg.To, ", ") } func writeAttachment(mw *mail.Writer, att Attachment) error { var h mail.AttachmentHeader h.SetContentType(att.MIMEType(), nil) h.SetFilename(att.Filename()) aw, err := mw.CreateAttachment(h) if err != nil { return fmt.Errorf("failed to create attachment: %v", err) } defer aw.Close() f, err := att.Open() if err != nil { return fmt.Errorf("failed to open attachment: %v", err) } defer f.Close() if _, err := io.Copy(aw, f); err != nil { return fmt.Errorf("failed to write attachment: %v", err) } if err := f.Close(); err != nil { return fmt.Errorf("failed to close attachment: %v", err) } if err := aw.Close(); err != nil { return fmt.Errorf("failed to close attachment writer: %v", err) } return nil } func (msg *OutgoingMessage) WriteTo(w io.Writer) error { from := []*mail.Address{{"", msg.From}} to := make([]*mail.Address, len(msg.To)) for i, addr := range msg.To { to[i] = &mail.Address{"", addr} } var h mail.Header h.SetDate(time.Now()) h.SetAddressList("From", from) h.SetAddressList("To", to) if msg.Subject != "" { h.SetText("Subject", msg.Subject) } if msg.InReplyTo != "" { h.Set("In-Reply-To", msg.InReplyTo) } h.Set("Message-Id", msg.MessageID) if msg.MessageID == "" { panic(fmt.Errorf("Attempting to send message without message ID")) } mw, err := mail.CreateWriter(w, h) if err != nil { return fmt.Errorf("failed to create mail writer: %v", err) } var th mail.InlineHeader th.Set("Content-Type", "text/plain; charset=utf-8") tw, err := mw.CreateSingleInline(th) if err != nil { return fmt.Errorf("failed to create text part: %v", err) } defer tw.Close() if _, err := io.WriteString(tw, msg.Text); err != nil { return fmt.Errorf("failed to write text part: %v", err) } if err := tw.Close(); err != nil { return fmt.Errorf("failed to close text part: %v", err) } for _, att := range msg.Attachments { if err := writeAttachment(mw, att); err != nil { return err } } if err := mw.Close(); err != nil { return fmt.Errorf("failed to close mail writer: %v", err) } return nil } func sendMessage(c *smtp.Client, msg *OutgoingMessage) error { if err := c.Mail(msg.From, nil); err != nil { return fmt.Errorf("MAIL FROM failed: %v", err) } for _, to := range msg.To { if err := c.Rcpt(to); err != nil { return fmt.Errorf("RCPT TO failed: %v", err) } } w, err := c.Data() if err != nil { return fmt.Errorf("DATA failed: %v", err) } defer w.Close() if err := msg.WriteTo(w); err != nil { return fmt.Errorf("failed to write outgoing message: %v", err) } if err := w.Close(); err != nil { return fmt.Errorf("failed to close SMTP data writer: %v", err) } return nil }