|
| 1 | +package imap |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "crypto/tls" |
| 6 | + "fmt" |
| 7 | + "log/slog" |
| 8 | + "net" |
| 9 | + "strconv" |
| 10 | + "time" |
| 11 | + |
| 12 | + goimap "github.com/emersion/go-imap/v2" |
| 13 | + "github.com/emersion/go-imap/v2/imapclient" |
| 14 | + "github.com/fastygo/framework/pkg/mail" |
| 15 | +) |
| 16 | + |
| 17 | +const ( |
| 18 | + idleReconnectDelay = 5 * time.Second |
| 19 | + defaultWatchMbox = "INBOX" |
| 20 | +) |
| 21 | + |
| 22 | +// Watch implements mail.Pusher with a dedicated IMAP connection running IDLE. |
| 23 | +// The primary Client connection stays free for ordinary commands. The returned |
| 24 | +// channel closes when ctx is cancelled or the watcher exits permanently. |
| 25 | +// |
| 26 | +// ChangeEvent.MailboxID is the mailbox SELECT'd for IDLE (Options.WatchMailbox |
| 27 | +// or INBOX). Events are mailbox-level only — callers re-query Messages. |
| 28 | +func (c *Client) Watch(ctx context.Context) (<-chan mail.ChangeEvent, error) { |
| 29 | + const op = "imap: IDLE" |
| 30 | + if !c.Capabilities().Push { |
| 31 | + return nil, &mail.Error{Op: op, Code: mail.CodeUnsupported, Err: fmt.Errorf("server does not advertise IDLE")} |
| 32 | + } |
| 33 | + if err := ctx.Err(); err != nil { |
| 34 | + return nil, wrapError(op, mail.CodeUnavailable, err) |
| 35 | + } |
| 36 | + |
| 37 | + mailbox := c.opts.WatchMailbox |
| 38 | + if mailbox == "" { |
| 39 | + mailbox = defaultWatchMbox |
| 40 | + } |
| 41 | + events := make(chan mail.ChangeEvent) |
| 42 | + go func() { |
| 43 | + defer close(events) |
| 44 | + auditEvent(ctx, slog.LevelInfo, "push_started", |
| 45 | + slog.String("op", op), |
| 46 | + slog.String("mailbox", mailbox)) |
| 47 | + defer auditEvent(ctx, slog.LevelInfo, "push_stopped", |
| 48 | + slog.String("op", op), |
| 49 | + slog.String("mailbox", mailbox)) |
| 50 | + |
| 51 | + for { |
| 52 | + if err := c.idleOnce(ctx, mailbox, events); err != nil { |
| 53 | + if ctx.Err() != nil { |
| 54 | + return |
| 55 | + } |
| 56 | + select { |
| 57 | + case <-ctx.Done(): |
| 58 | + return |
| 59 | + case <-time.After(idleReconnectDelay): |
| 60 | + } |
| 61 | + continue |
| 62 | + } |
| 63 | + if ctx.Err() != nil { |
| 64 | + return |
| 65 | + } |
| 66 | + } |
| 67 | + }() |
| 68 | + return events, nil |
| 69 | +} |
| 70 | + |
| 71 | +func (c *Client) idleOnce(ctx context.Context, mailbox string, events chan<- mail.ChangeEvent) error { |
| 72 | + const op = "imap: IDLE" |
| 73 | + ic, err := c.openIdleClient(ctx, mailbox, events) |
| 74 | + if err != nil { |
| 75 | + return err |
| 76 | + } |
| 77 | + defer func() { |
| 78 | + _ = ic.Logout().Wait() |
| 79 | + _ = ic.Close() |
| 80 | + }() |
| 81 | + |
| 82 | + idleCmd, err := ic.Idle() |
| 83 | + if err != nil { |
| 84 | + return wrapError(op, mail.CodeUnavailable, err) |
| 85 | + } |
| 86 | + |
| 87 | + waitDone := make(chan error, 1) |
| 88 | + go func() { |
| 89 | + waitDone <- idleCmd.Wait() |
| 90 | + }() |
| 91 | + |
| 92 | + select { |
| 93 | + case <-ctx.Done(): |
| 94 | + _ = idleCmd.Close() |
| 95 | + <-waitDone |
| 96 | + return ctx.Err() |
| 97 | + case err := <-waitDone: |
| 98 | + _ = idleCmd.Close() |
| 99 | + if err != nil { |
| 100 | + return wrapError(op, mail.CodeUnavailable, err) |
| 101 | + } |
| 102 | + return nil |
| 103 | + } |
| 104 | +} |
| 105 | + |
| 106 | +func (c *Client) openIdleClient(ctx context.Context, mailbox string, events chan<- mail.ChangeEvent) (*imapclient.Client, error) { |
| 107 | + const op = "imap: IDLE connect" |
| 108 | + emit := func(ev mail.ChangeEvent) { |
| 109 | + select { |
| 110 | + case events <- ev: |
| 111 | + case <-ctx.Done(): |
| 112 | + } |
| 113 | + } |
| 114 | + handler := &imapclient.UnilateralDataHandler{ |
| 115 | + Expunge: func(uint32) { |
| 116 | + emit(mail.ChangeEvent{MailboxID: mailbox}) |
| 117 | + }, |
| 118 | + Mailbox: func(data *imapclient.UnilateralDataMailbox) { |
| 119 | + if data == nil { |
| 120 | + return |
| 121 | + } |
| 122 | + emit(mail.ChangeEvent{MailboxID: mailbox}) |
| 123 | + }, |
| 124 | + Fetch: func(*imapclient.FetchMessageData) { |
| 125 | + emit(mail.ChangeEvent{MailboxID: mailbox}) |
| 126 | + }, |
| 127 | + } |
| 128 | + |
| 129 | + tlsConfig := &tls.Config{ |
| 130 | + ServerName: c.opts.IMAPHost, |
| 131 | + InsecureSkipVerify: c.opts.InsecureTLS, //nolint:gosec // explicit development-only option |
| 132 | + } |
| 133 | + imapOpts := &imapclient.Options{ |
| 134 | + TLSConfig: tlsConfig, |
| 135 | + UnilateralDataHandler: handler, |
| 136 | + } |
| 137 | + |
| 138 | + var ( |
| 139 | + ic *imapclient.Client |
| 140 | + err error |
| 141 | + ) |
| 142 | + if c.opts.DialIMAP != nil { |
| 143 | + var conn net.Conn |
| 144 | + conn, err = c.opts.DialIMAP(ctx) |
| 145 | + if err == nil { |
| 146 | + ic = imapclient.New(conn, imapOpts) |
| 147 | + } |
| 148 | + } else { |
| 149 | + ic, err = imapclient.DialTLS(net.JoinHostPort(c.opts.IMAPHost, strconv.Itoa(c.opts.IMAPPort)), imapOpts) |
| 150 | + } |
| 151 | + if err != nil { |
| 152 | + return nil, wrapError(op, mail.CodeUnavailable, err) |
| 153 | + } |
| 154 | + if err := ctx.Err(); err != nil { |
| 155 | + _ = ic.Close() |
| 156 | + return nil, wrapError(op, mail.CodeUnavailable, err) |
| 157 | + } |
| 158 | + if err := ic.Login(c.opts.Username, c.opts.Password).Wait(); err != nil { |
| 159 | + _ = ic.Close() |
| 160 | + return nil, wrapError(op, mail.CodeAuth, err) |
| 161 | + } |
| 162 | + if _, err := ic.Select(mailbox, nil).Wait(); err != nil { |
| 163 | + _ = ic.Logout().Wait() |
| 164 | + _ = ic.Close() |
| 165 | + return nil, wrapError(op, mail.CodeNotFound, err) |
| 166 | + } |
| 167 | + return ic, nil |
| 168 | +} |
| 169 | + |
| 170 | +func supportsIdle(caps goimap.CapSet) bool { |
| 171 | + return caps.Has(goimap.CapIdle) || caps.Has(goimap.CapIMAP4rev2) |
| 172 | +} |
0 commit comments