smtp/server.go

   1 // mailpopbox
   2 // Copyright 2020 Blue Static <https://www.bluestatic.org>
   3 // This program is free software licensed under the GNU General Public License,
   4 // version 3.0. The full text of the license can be found in LICENSE.txt.
   5 // SPDX-License-Identifier: GPL-3.0-only
   6
   7 package smtp
   8
   9 import (
  10         "crypto/tls"
  11         "fmt"
  12         "io"
  13         "net"
  14         "net/mail"
  15         "time"
  16 )
  17
  18 type ReplyLine struct {
  19         Code    int
  20         Message string
  21 }
  22
  23 func (l ReplyLine) String() string {
  24         return fmt.Sprintf("%d %s", l.Code, l.Message)
  25 }
  26
  27 var (
  28         ReplyOK          = ReplyLine{250, "OK"}
  29         ReplyBadSyntax   = ReplyLine{501, "syntax error"}
  30         ReplyBadSequence = ReplyLine{503, "bad sequence of commands"}
  31         ReplyBadMailbox  = ReplyLine{550, "mailbox unavailable"}
  32 )
  33
  34 type Envelope struct {
  35         RemoteAddr net.Addr
  36         EHLO       string
  37         MailFrom   mail.Address
  38         RcptTo     []mail.Address
  39         Data       []byte
  40         Received   time.Time
  41         ID         string
  42 }
  43
  44 func WriteEnvelopeForDelivery(w io.Writer, e Envelope) {
  45         fmt.Fprintf(w, "Delivered-To: <%s>\r\n", e.RcptTo[0].Address)
  46         fmt.Fprintf(w, "Return-Path: <%s>\r\n", e.MailFrom.Address)
  47         w.Write(e.Data)
  48 }
  49
  50 type Server interface {
  51         Name() string
  52         TLSConfig() *tls.Config
  53         OnEHLO() *ReplyLine
  54         VerifyAddress(mail.Address) ReplyLine
  55         OnMessageDelivered(Envelope) *ReplyLine
  56 }
  57
  58 type EmptyServerCallbacks struct{}
  59
  60 func (*EmptyServerCallbacks) TLSConfig() *tls.Config {
  61         return nil
  62 }
  63
  64 func (*EmptyServerCallbacks) OnEHLO() *ReplyLine {
  65         return nil
  66 }
  67
  68 func (*EmptyServerCallbacks) VerifyAddress(mail.Address) ReplyLine {
  69         return ReplyOK
  70 }
  71
  72 func (*EmptyServerCallbacks) OnMessageDelivered(Envelope) *ReplyLine {
  73         return nil
  74 }