mox/smtpserver/dsn.go
Mechiel Lukkien dcb0f0a82c
in DSNs, add a References header pointing to the message with deliverability issues
so mail user agents will show DSNs threaded/grouped with the original message.
we store the MessageID in the message queue, so we have the value within reach
when we need it.

i saw a references header in a DSN from gmail on a test account. makes sense to me.
2023-07-23 17:56:39 +02:00

56 lines
1.5 KiB
Go

package smtpserver
import (
"context"
"fmt"
"os"
"github.com/mjl-/mox/dsn"
"github.com/mjl-/mox/queue"
"github.com/mjl-/mox/smtp"
"github.com/mjl-/mox/store"
)
// compose dsn message and add it to the queue for delivery to rcptTo.
func queueDSN(ctx context.Context, c *conn, rcptTo smtp.Path, m dsn.Message) error {
buf, err := m.Compose(c.log, false)
if err != nil {
return err
}
var bufUTF8 []byte
if c.smtputf8 {
bufUTF8, err = m.Compose(c.log, true)
if err != nil {
c.log.Errorx("composing dsn with utf-8 for incoming delivery for unknown user, continuing with ascii-only dsn", err)
}
}
f, err := store.CreateMessageTemp("smtp-dsn")
if err != nil {
return fmt.Errorf("creating temp file: %w", err)
}
defer func() {
if f != nil {
err := os.Remove(f.Name())
c.log.Check(err, "removing temporary dsn message file")
err = f.Close()
c.log.Check(err, "closing temporary dsn message file")
}
}()
if _, err := f.Write([]byte(buf)); err != nil {
return fmt.Errorf("writing dsn file: %w", err)
}
// Queue DSN with null reverse path so failures to deliver will eventually drop the
// message instead of causing delivery loops.
// ../rfc/3464:433
const has8bit = false
const smtputf8 = false
if _, err := queue.Add(ctx, c.log, "", smtp.Path{}, rcptTo, has8bit, smtputf8, int64(len(buf)), m.MessageID, nil, f, bufUTF8, true); err != nil {
return err
}
err = f.Close()
c.log.Check(err, "closing dsn file")
f = nil
return nil
}