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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)
}
builder.WriteString("\n")
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 {
fromAddr, err := mail.ParseAddress(msg.From)
if err != nil {
return err
}
from := []*mail.Address{fromAddr}
to := make([]*mail.Address, len(msg.To))
for i, rcpt := range msg.To {
addr, err := mail.ParseAddress(rcpt)
if err != nil {
return err
}
to[i] = 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 {
addr, _ := mail.ParseAddress(msg.From)
if err := c.Mail(addr.Address, nil); err != nil {
return fmt.Errorf("MAIL FROM failed: %v", err)
}
for _, to := range msg.To {
addr, _ := mail.ParseAddress(to)
if err := c.Rcpt(addr.Address); err != nil {
return fmt.Errorf("RCPT TO failed: %v (%s)", err, addr.Address)
}
}
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
}
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