pop3.go

   1 package main
   2
   3 import (
   4         "crypto/tls"
   5         "errors"
   6         "fmt"
   7         "io"
   8         "io/ioutil"
   9         "net"
  10         "os"
  11         "path"
  12
  13         "src.bluestatic.org/mailpopbox/pop3"
  14 )
  15
  16 func runPOP3Server(config Config) <-chan error {
  17         server := pop3Server{
  18                 config: config,
  19                 rc:     make(chan error),
  20         }
  21         go server.run()
  22         return server.rc
  23 }
  24
  25 type pop3Server struct {
  26         config Config
  27         rc     chan error
  28 }
  29
  30 func (server *pop3Server) run() {
  31         for _, s := range server.config.Servers {
  32                 if err := os.Mkdir(s.MaildropPath, 0700); err != nil && !os.IsExist(err) {
  33                         server.rc <- err
  34                 }
  35         }
  36
  37         tlsConfig, err := server.config.GetTLSConfig()
  38         if err != nil {
  39                 server.rc <- err
  40                 return
  41         }
  42
  43         addr := fmt.Sprintf(":%d", server.config.POP3Port)
  44
  45         var l net.Listener
  46         if tlsConfig == nil {
  47                 l, err = net.Listen("tcp", addr)
  48         } else {
  49                 l, err = tls.Listen("tcp", addr, tlsConfig)
  50         }
  51         if err != nil {
  52                 server.rc <- err
  53                 return
  54         }
  55
  56         for {
  57                 conn, err := l.Accept()
  58                 if err != nil {
  59                         server.rc <- err
  60                         break
  61                 }
  62
  63                 go pop3.AcceptConnection(conn, server)
  64         }
  65 }
  66
  67 func (server *pop3Server) Name() string {
  68         return server.config.Hostname
  69 }
  70
  71 func (server *pop3Server) OpenMailbox(user, pass string) (pop3.Mailbox, error) {
  72         for _, s := range server.config.Servers {
  73                 if user == "mailbox@"+s.Domain && pass == s.MailboxPassword {
  74                         return server.openMailbox(s.MaildropPath)
  75                 }
  76         }
  77         return nil, errors.New("permission denied")
  78 }
  79
  80 func (server *pop3Server) openMailbox(maildrop string) (*mailbox, error) {
  81         files, err := ioutil.ReadDir(maildrop)
  82         if err != nil {
  83                 // TODO: hide error, log instead
  84                 return nil, err
  85         }
  86
  87         mb := &mailbox{
  88                 messages: make([]message, 0, len(files)),
  89         }
  90
  91         i := 0
  92         for _, file := range files {
  93                 if file.IsDir() {
  94                         continue
  95                 }
  96
  97                 msg := message{
  98                         filename: path.Join(maildrop, file.Name()),
  99                         index:    i,
 100                         size:     file.Size(),
 101                 }
 102                 mb.messages = append(mb.messages, msg)
 103                 i++
 104         }
 105
 106         return mb, nil
 107 }
 108
 109 type mailbox struct {
 110         messages []message
 111 }
 112
 113 type message struct {
 114         filename string
 115         index    int
 116         size     int64
 117         deleted  bool
 118 }
 119
 120 func (m message) ID() int {
 121         return m.index + 1
 122 }
 123
 124 func (m message) Size() int {
 125         return int(m.size)
 126 }
 127
 128 func (m message) Deleted() bool {
 129         return m.deleted
 130 }
 131
 132 func (mb *mailbox) ListMessages() ([]pop3.Message, error) {
 133         msgs := make([]pop3.Message, len(mb.messages))
 134         for i := 0; i < len(mb.messages); i++ {
 135                 msgs[i] = &mb.messages[i]
 136         }
 137         return msgs, nil
 138 }
 139
 140 func (mb *mailbox) GetMessage(id int) pop3.Message {
 141         if id > len(mb.messages) {
 142                 return nil
 143         }
 144         return &mb.messages[id-1]
 145 }
 146
 147 func (mb *mailbox) Retrieve(msg pop3.Message) (io.ReadCloser, error) {
 148         filename := msg.(*message).filename
 149         return os.Open(filename)
 150 }
 151
 152 func (mb *mailbox) Delete(msg pop3.Message) error {
 153         msg.(*message).deleted = true
 154         return nil
 155 }
 156
 157 func (mb *mailbox) Close() error {
 158         for _, message := range mb.messages {
 159                 if message.deleted {
 160                         os.Remove(message.filename)
 161                 }
 162         }
 163         return nil
 164 }
 165
 166 func (mb *mailbox) Reset() {
 167         for _, message := range mb.messages {
 168                 message.deleted = false
 169         }
 170 }