smtp/server.go

   1 package smtp
   2
   3 import (
   4         "crypto/tls"
   5         "regexp"
   6         "fmt"
   7         "io"
   8         "net"
   9         "net/mail"
  10         "strings"
  11         "time"
  12 )
  13
  14 type ReplyLine struct {
  15         Code    int
  16         Message string
  17 }
  18
  19 func (l ReplyLine) String() string {
  20         return fmt.Sprintf("%d %s", l.Code, l.Message)
  21 }
  22
  23 var SendAsSubject = regexp.MustCompile(`(?i)\[sendas:\s*([a-zA-Z0-9\.\-_]+)\]`)
  24
  25 var (
  26         ReplyOK               = ReplyLine{250, "OK"}
  27         ReplyBadSyntax        = ReplyLine{501, "syntax error"}
  28         ReplyBadSequence      = ReplyLine{503, "bad sequence of commands"}
  29         ReplyBadMailbox       = ReplyLine{550, "mailbox unavailable"}
  30         ReplyMailboxUnallowed = ReplyLine{553, "mailbox name not allowed"}
  31 )
  32
  33 func DomainForAddress(addr mail.Address) string {
  34         return DomainForAddressString(addr.Address)
  35 }
  36
  37 func DomainForAddressString(address string) string {
  38         domainIdx := strings.LastIndex(address, "@")
  39         if domainIdx == -1 {
  40                 return ""
  41         }
  42         return address[domainIdx+1:]
  43 }
  44
  45 type Envelope struct {
  46         RemoteAddr net.Addr
  47         EHLO       string
  48         MailFrom   mail.Address
  49         RcptTo     []mail.Address
  50         Data       []byte
  51         Received   time.Time
  52         ID         string
  53 }
  54
  55 func WriteEnvelopeForDelivery(w io.Writer, e Envelope) {
  56         fmt.Fprintf(w, "Delivered-To: <%s>\r\n", e.RcptTo[0].Address)
  57         fmt.Fprintf(w, "Return-Path: <%s>\r\n", e.MailFrom.Address)
  58         w.Write(e.Data)
  59 }
  60
  61 type Server interface {
  62         Name() string
  63         TLSConfig() *tls.Config
  64         VerifyAddress(mail.Address) ReplyLine
  65         // Verify that the authc+passwd identity can send mail as authz.
  66         Authenticate(authz, authc, passwd string) bool
  67         OnMessageDelivered(Envelope) *ReplyLine
  68
  69         // RelayMessage instructs the server to send the Envelope to another
  70         // MTA for outbound delivery.
  71         RelayMessage(Envelope)
  72 }
  73
  74 type EmptyServerCallbacks struct{}
  75
  76 func (*EmptyServerCallbacks) TLSConfig() *tls.Config {
  77         return nil
  78 }
  79
  80 func (*EmptyServerCallbacks) VerifyAddress(mail.Address) ReplyLine {
  81         return ReplyOK
  82 }
  83
  84 func (*EmptyServerCallbacks) Authenticate(authz, authc, passwd string) bool {
  85         return false
  86 }
  87
  88 func (*EmptyServerCallbacks) OnMessageDelivered(Envelope) *ReplyLine {
  89         return nil
  90 }
  91
  92 func (*EmptyServerCallbacks) RelayMessage(Envelope) {
  93 }