Import/Export backend prep

internal/transfer/provider_mbox_target.go

@@ -0,0 +1,97 @@
+// 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 (
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/emersion/go-mbox"
+	"github.com/hashicorp/go-multierror"
+)
+
+// DefaultMailboxes returns the default mailboxes for default rules if no other is found.
+func (p *MBOXProvider) DefaultMailboxes(sourceMailbox Mailbox) []Mailbox {
+	return []Mailbox{{
+		Name: sourceMailbox.Name,
+	}}
+}
+
+// CreateMailbox does nothing. Files are created dynamically during the import.
+func (p *MBOXProvider) CreateMailbox(mailbox Mailbox) (Mailbox, error) {
+	return mailbox, nil
+}
+
+// TransferFrom imports messages from channel.
+func (p *MBOXProvider) TransferFrom(rules transferRules, progress *Progress, ch <-chan Message) {
+	log.Info("Started transfer from channel to MBOX")
+	defer log.Info("Finished transfer from channel to MBOX")
+
+	for msg := range ch {
+		for progress.shouldStop() {
+			break
+		}
+
+		err := p.writeMessage(msg)
+		progress.messageImported(msg.ID, "", err)
+	}
+}
+
+func (p *MBOXProvider) writeMessage(msg Message) error {
+	var multiErr error
+	for _, mailbox := range msg.Targets {
+		mboxName := filepath.Base(mailbox.Name)
+		if !strings.HasSuffix(mboxName, ".mbox") {
+			mboxName += ".mbox"
+		}
+
+		mboxPath := filepath.Join(p.root, mboxName)
+		mboxFile, err := os.OpenFile(mboxPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
+		if err != nil {
+			multiErr = multierror.Append(multiErr, err)
+			continue
+		}
+
+		msgFrom := ""
+		msgTime := time.Now()
+		if header, err := getMessageHeader(msg.Body); err == nil {
+			if date, err := header.Date(); err == nil {
+				msgTime = date
+			}
+			if addresses, err := header.AddressList("from"); err == nil && len(addresses) > 0 {
+				msgFrom = addresses[0].Address
+			}
+		}
+
+		mboxWriter := mbox.NewWriter(mboxFile)
+		messageWriter, err := mboxWriter.CreateMessage(msgFrom, msgTime)
+		if err != nil {
+			multiErr = multierror.Append(multiErr, err)
+			continue
+		}
+
+		_, err = messageWriter.Write(msg.Body)
+		if err != nil {
+			multiErr = multierror.Append(multiErr, err)
+			continue
+		}
+	}
+	return multiErr
+}