smtp/server.go

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