package imap
import (
"crypto/tls"
"fmt"
"math"
"net"
"net/url"
"time"
"github.com/emersion/go-imap"
sortthread "github.com/emersion/go-imap-sortthread"
"github.com/emersion/go-imap/client"
"github.com/pkg/errors"
"git.sr.ht/~rjarry/aerc/lib"
"git.sr.ht/~rjarry/aerc/models"
"git.sr.ht/~rjarry/aerc/worker/handlers"
"git.sr.ht/~rjarry/aerc/worker/types"
)
func init() {
handlers.RegisterWorkerFactory("imap", NewIMAPWorker)
handlers.RegisterWorkerFactory("imaps", NewIMAPWorker)
}
var (
errUnsupported = fmt.Errorf("unsupported command")
errNotConnected = fmt.Errorf("not connected")
errAlreadyConnected = fmt.Errorf("already connected")
)
type imapClient struct {
*client.Client
thread *sortthread.ThreadClient
sort *sortthread.SortClient
}
type imapConfig struct {
scheme string
insecure bool
addr string
user *url.Userinfo
folders []string
oauthBearer lib.OAuthBearer
idle_timeout time.Duration
// tcp connection parameters
connection_timeout time.Duration
keepalive_period time.Duration
keepalive_probes int
keepalive_interval int
}
type IMAPWorker struct {
config imapConfig
client *imapClient
selected *imap.MailboxStatus
updates chan client.Update
worker *types.Worker
// Map of sequence numbers to UIDs, index 0 is seq number 1
seqMap []uint32
done chan struct{}
autoReconnect bool
retries int
idler *idler
}
func NewIMAPWorker(worker *types.Worker) (types.Backend, error) {
return &IMAPWorker{
updates: make(chan client.Update, 50),
worker: worker,
selected: &imap.MailboxStatus{},
idler: newIdler(imapConfig{}, worker),
}, nil
}
func (w *IMAPWorker) newClient(c *client.Client) {
c.Updates = w.updates
w.client = &imapClient{c, sortthread.NewThreadClient(c), sortthread.NewSortClient(c)}
w.idler.SetClient(w.client)
}
func (w *IMAPWorker) handleMessage(msg types.WorkerMessage) error {
defer func() {
w.idler.Start()
}()
if err := w.idler.Stop(); err != nil {
return err
}
var reterr error // will be returned at the end, needed to support idle
checkConn := func(wait time.Duration) {
time.Sleep(wait)
w.stopConnectionObserver()
w.startConnectionObserver()
}
// set connection timeout for calls to imap server
if w.client != nil {
w.client.Timeout = w.config.connection_timeout
}
switch msg := msg.(type) {
case *types.Unsupported:
// No-op
case *types.Configure:
reterr = w.handleConfigure(msg)
case *types.Connect:
if w.client != nil && w.client.State() == imap.SelectedState {
if !w.autoReconnect {
w.autoReconnect = true
checkConn(0)
}
reterr = errAlreadyConnected
break
}
w.autoReconnect = true
c, err := w.connect()
if err != nil {
checkConn(0)
reterr = err
break
}
w.stopConnectionObserver()
w.newClient(c)
w.startConnectionObserver()
w.worker.PostMessage(&types.Done{Message: types.RespondTo(msg)}, nil)
case *types.Reconnect:
if !w.autoReconnect {
reterr = fmt.Errorf("auto-reconnect is disabled; run connect to enable it")
break
}
c, err := w.connect()
if err != nil {
wait, msg := w.exponentialBackoff()
go checkConn(wait)
w.retries++
reterr = errors.Wrap(err, msg)
break
}
w.stopConnectionObserver()
w.newClient(c)
w.startConnectionObserver()
w.worker.PostMessage(&types.Done{Message: types.RespondTo(msg)}, nil)
case *types.Disconnect:
w.autoReconnect = false
w.stopConnectionObserver()
if w.client == nil || w.client.State() != imap.SelectedState {
reterr = errNotConnected
break
}
if err := w.client.Logout(); err != nil {
reterr = err
break
}
w.worker.PostMessage(&types.Done{Message: types.RespondTo(msg)}, nil)
case *types.ListDirectories:
w.handleListDirectories(msg)
case *types.OpenDirectory:
w.handleOpenDirectory(msg)
case *types.FetchDirectoryContents:
w.handleFetchDirectoryContents(msg)
case *types.FetchDirectoryThreaded:
w.handleDirectoryThreaded(msg)
case *types.CreateDirectory:
w.handleCreateDirectory(msg)
case *types.RemoveDirectory:
w.handleRemoveDirectory(msg)
case *types.FetchMessageHeaders:
w.handleFetchMessageHeaders(msg)
case *types.FetchMessageBodyPart:
w.handleFetchMessageBodyPart(msg)
case *types.FetchFullMessages:
w.handleFetchFullMessages(msg)
case *types.DeleteMessages:
w.handleDeleteMessages(msg)
case *types.FlagMessages:
w.handleFlagMessages(msg)
case *types.AnsweredMessages:
w.handleAnsweredMessages(msg)
case *types.CopyMessages:
w.handleCopyMessages(msg)
case *types.AppendMessage:
w.handleAppendMessage(msg)
case *types.SearchDirectory:
w.handleSearchDirectory(msg)
default:
reterr = errUnsupported
}
// we don't want idle to timeout, so set timeout to zero
if w.client != nil {
w.client.Timeout = 0
}
return reterr
}
func (w *IMAPWorker) handleImapUpdate(update client.Update) {
w.worker.Logger.Printf("(= %T", update)
checkBounds := func(idx, size int) bool {
if idx < 0 || idx >= size {
return false
}
return true
}
switch update := update.(type) {
case *client.MailboxUpdate:
status := update.Mailbox
if w.selected.Name == status.Name {
w.selected = status
}
w.worker.PostMessage(&types.DirectoryInfo{
Info: &models.DirectoryInfo{
Flags: status.Flags,
Name: status.Name,
ReadOnly: status.ReadOnly,
Exists: int(status.Messages),
Recent: int(status.Recent),
Unseen: int(status.Unseen),
},
}, nil)
case *client.MessageUpdate:
msg := update.Message
if msg.Uid == 0 {
if ok := checkBounds(int(msg.SeqNum)-1, len(w.seqMap)); !ok {
w.worker.Logger.Println("MessageUpdate error: index out of range")
return
}
msg.Uid = w.seqMap[msg.SeqNum-1]
}
w.worker.PostMessage(&types.MessageInfo{
Info: &models.MessageInfo{
BodyStructure: translateBodyStructure(msg.BodyStructure),
Envelope: translateEnvelope(msg.Envelope),
Flags: translateImapFlags(msg.Flags),
InternalDate: msg.InternalDate,
Uid: msg.Uid,
},
}, nil)
case *client.ExpungeUpdate:
i := update.SeqNum - 1
if ok := checkBounds(int(i), len(w.seqMap)); !ok {
w.worker.Logger.Println("ExpungeUpdate error: index out of range")
return
}
uid := w.seqMap[i]
w.seqMap = append(w.seqMap[:i], w.seqMap[i+1:]...)
w.worker.PostMessage(&types.MessagesDeleted{
Uids: []uint32{uid},
}, nil)
}
}
func (w *IMAPWorker) exponentialBackoff() (time.Duration, string) {
maxWait := 16
if w.retries > 0 {
backoff := int(math.Pow(2.0, float64(w.retries)))
if backoff > maxWait {
backoff = maxWait
}
waitStr := fmt.Sprintf("%ds", backoff)
wait, err := time.ParseDuration(waitStr)
if err == nil {
return wait, fmt.Sprintf("wait %s before reconnect", waitStr)
}
}
return 0 * time.Second, ""
}
func (w *IMAPWorker) startConnectionObserver() {
emitConnErr := func(errMsg string) {
w.worker.PostMessage(&types.ConnError{
Error: fmt.Errorf(errMsg),
}, nil)
}
if w.client == nil {
emitConnErr("imap client not connected")
return
}
go func() {
select {
case <-w.client.LoggedOut():
if w.autoReconnect {
emitConnErr("imap: logged out")
}
case <-w.done:
return
}
}()
}
func (w *IMAPWorker) stopConnectionObserver() {
if w.done != nil {
close(w.done)
}
w.done = make(chan struct{})
}
func (w *IMAPWorker) connect() (*client.Client, error) {
var (
conn *net.TCPConn
c *client.Client
)
addr, err := net.ResolveTCPAddr("tcp", w.config.addr)
if err != nil {
return nil, err
}
conn, err = net.DialTCP("tcp", nil, addr)
if err != nil {
return nil, err
}
if w.config.connection_timeout > 0 {
end := time.Now().Add(w.config.connection_timeout)
err = conn.SetDeadline(end)
if err != nil {
return nil, err
}
}
if w.config.keepalive_period > 0 {
err = w.setKeepaliveParameters(conn)
if err != nil {
return nil, err
}
}
serverName, _, _ := net.SplitHostPort(w.config.addr)
tlsConfig := &tls.Config{ServerName: serverName}
switch w.config.scheme {
case "imap":
c, err = client.New(conn)
if err != nil {
return nil, err
}
if !w.config.insecure {
if err = c.StartTLS(tlsConfig); err != nil {
return nil, err
}
}
case "imaps":
tlsConn := tls.Client(conn, tlsConfig)
c, err = client.New(tlsConn)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("Unknown IMAP scheme %s", w.config.scheme)
}
c.ErrorLog = w.worker.Logger
if w.config.user != nil {
username := w.config.user.Username()
password, hasPassword := w.config.user.Password()
if !hasPassword {
// TODO: ask password
}
if w.config.oauthBearer.Enabled {
if err := w.config.oauthBearer.Authenticate(
username, password, c); err != nil {
return nil, err
}
} else if err := c.Login(username, password); err != nil {
return nil, err
}
}
c.SetDebug(w.worker.Logger.Writer())
if _, err := c.Select(imap.InboxName, false); err != nil {
return nil, err
}
w.retries = 0
return c, nil
}
// Set additional keepalive parameters.
// Uses new interfaces introduced in Go1.11, which let us get connection's file
// descriptor, without blocking, and therefore without uncontrolled spawning of
// threads (not goroutines, actual threads).
func (w *IMAPWorker) setKeepaliveParameters(conn *net.TCPConn) error {
err := conn.SetKeepAlive(true)
if err != nil {
return err
}
// Idle time before sending a keepalive probe
err = conn.SetKeepAlivePeriod(w.config.keepalive_period)
if err != nil {
return err
}
rawConn, e := conn.SyscallConn()
if e != nil {
return e
}
err = rawConn.Control(func(fdPtr uintptr) {
fd := int(fdPtr)
// Max number of probes before failure
err := lib.SetTcpKeepaliveProbes(fd, w.config.keepalive_probes)
if err != nil {
w.worker.Logger.Printf(
"cannot set tcp keepalive probes: %v\n", err)
}
// Wait time after an unsuccessful probe
err = lib.SetTcpKeepaliveInterval(fd, w.config.keepalive_interval)
if err != nil {
w.worker.Logger.Printf(
"cannot set tcp keepalive interval: %v\n", err)
}
})
return err
}
func (w *IMAPWorker) Run() {
for {
select {
case msg := <-w.worker.Actions:
msg = w.worker.ProcessAction(msg)
if err := w.handleMessage(msg); err == errUnsupported {
w.worker.PostMessage(&types.Unsupported{
Message: types.RespondTo(msg),
}, nil)
} else if err != nil {
w.worker.PostMessage(&types.Error{
Message: types.RespondTo(msg),
Error: err,
}, nil)
}
case update := <-w.updates:
w.handleImapUpdate(update)
}
}
}
