pop3.go

   1 package main
   2
   3 import (
   4         "errors"
   5         "fmt"
   6         "io"
   7         "net"
   8         "os"
   9
  10         "src.bluestatic.org/mailpopbox/pop3"
  11 )
  12
  13 func runPOP3Server(config Config) <-chan error {
  14         server := pop3Server{
  15                 config: config,
  16                 rc:     make(chan error),
  17         }
  18         go server.run()
  19         return server.rc
  20 }
  21
  22 type pop3Server struct {
  23         config Config
  24         rc     chan error
  25 }
  26
  27 func (server *pop3Server) run() {
  28         for _, s := range server.config.Servers {
  29                 if err := os.Mkdir(s.MaildropPath, 0700); err != nil && !os.IsExist(err) {
  30                         server.rc <- err
  31                 }
  32         }
  33
  34         l, err := net.Listen("tcp", fmt.Sprintf(":%d", server.config.POP3Port))
  35         if err != nil {
  36                 server.rc <- err
  37                 return
  38         }
  39
  40         for {
  41                 conn, err := l.Accept()
  42                 if err != nil {
  43                         server.rc <- err
  44                         break
  45                 }
  46
  47                 go pop3.AcceptConnection(conn, server)
  48         }
  49 }
  50
  51 func (server *pop3Server) Name() string {
  52         return server.config.Hostname
  53 }
  54
  55 func (server *pop3Server) OpenMailbox(user, pass string) (pop3.Mailbox, error) {
  56         for _, s := range server.config.Servers {
  57                 if user == "mailbox@"+s.Domain && pass == s.MailboxPassword {
  58                         return server.openMailbox(s.MaildropPath)
  59                 }
  60         }
  61         return nil, errors.New("permission denied")
  62 }
  63
  64 func (server *pop3Server) openMailbox(maildrop string) (*mailbox, error) {
  65         mb := &mailbox{
  66                 messages: make([]message, 0),
  67         }
  68         return mb, nil
  69 }
  70
  71 type mailbox struct {
  72         messages []message
  73 }
  74
  75 type message struct {
  76         filename string
  77         index    int
  78         size     int
  79         deleted  bool
  80 }
  81
  82 func (m message) ID() int {
  83         return m.index + 1
  84 }
  85
  86 func (m message) Size() int {
  87         return m.size
  88 }
  89
  90 func (mb *mailbox) ListMessages() ([]pop3.Message, error) {
  91         msgs := make([]pop3.Message, len(mb.messages))
  92         for i := 0; i < len(mb.messages); i++ {
  93                 msgs[i] = &mb.messages[i]
  94         }
  95         return msgs, nil
  96 }
  97
  98 func (mb *mailbox) Retrieve(msg pop3.Message) (io.ReadCloser, error) {
  99         filename := msg.(*message).filename
 100         return os.Open(filename)
 101 }
 102
 103 func (mb *mailbox) Delete(msg pop3.Message) error {
 104         message := msg.(*message)
 105         if message.deleted {
 106                 return errors.New("already deleted")
 107         }
 108         message.deleted = true
 109         return nil
 110 }
 111
 112 func (mb *mailbox) Close() error {
 113         for _, message := range mb.messages {
 114                 if message.deleted {
 115                         os.Remove(message.filename)
 116                 }
 117         }
 118         return nil
 119 }
 120
 121 func (mb *mailbox) Reset() {
 122         for _, message := range mb.messages {
 123                 message.deleted = false
 124         }
 125 }