Import/Export backend prep

internal/transfer/provider_imap.go

@@ -0,0 +1,98 @@
+// Copyright (c) 2020 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package transfer
+
+import (
+	"net"
+	"strings"
+
+	imapClient "github.com/emersion/go-imap/client"
+)
+
+// IMAPProvider implements export from IMAP server.
+type IMAPProvider struct {
+	username string
+	password string
+	addr     string
+
+	client *imapClient.Client
+}
+
+// NewIMAPProvider returns new IMAPProvider.
+func NewIMAPProvider(username, password, host, port string) (*IMAPProvider, error) {
+	p := &IMAPProvider{
+		username: username,
+		password: password,
+		addr:     net.JoinHostPort(host, port),
+	}
+
+	if err := p.auth(); err != nil {
+		return nil, err
+	}
+
+	return p, nil
+}
+
+// ID is used for generating transfer ID by combining source and target ID.
+// We want to keep the same rules for import from any IMAP server, therefore
+// it returns constant.
+func (p *IMAPProvider) ID() string {
+	return "imap"
+}
+
+// Mailboxes returns all available folder names from root of EML files.
+// In case the same folder name is used more than once (for example root/a/foo
+// and root/b/foo), it's treated as the same folder.
+func (p *IMAPProvider) Mailboxes(includEmpty, includeAllMail bool) ([]Mailbox, error) {
+	mailboxesInfo, err := p.list()
+	if err != nil {
+		return nil, err
+	}
+
+	mailboxes := []Mailbox{}
+	for _, mailbox := range mailboxesInfo {
+		hasNoSelect := false
+		for _, attrib := range mailbox.Attributes {
+			if strings.ToLower(attrib) == "\\noselect" {
+				hasNoSelect = true
+				break
+			}
+		}
+		if hasNoSelect || mailbox.Name == "[Gmail]" {
+			continue
+		}
+
+		if !includEmpty || true {
+			mailboxStatus, err := p.selectIn(mailbox.Name)
+			if err != nil {
+				return nil, err
+			}
+			if mailboxStatus.Messages == 0 {
+				continue
+			}
+		}
+
+		mailboxes = append(mailboxes, Mailbox{
+			ID:          "",
+			Name:        mailbox.Name,
+			Color:       "",
+			IsExclusive: false,
+		})
+	}
+	return mailboxes, nil
+}