Import/Export backend prep

internal/transfer/provider_eml_target.go

@@ -0,0 +1,89 @@
+// 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 (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/hashicorp/go-multierror"
+)
+
+// DefaultMailboxes returns the default mailboxes for default rules if no other is found.
+func (p *EMLProvider) DefaultMailboxes(sourceMailbox Mailbox) []Mailbox {
+	return []Mailbox{{
+		Name: sourceMailbox.Name,
+	}}
+}
+
+// CreateMailbox does nothing. Folders are created dynamically during the import.
+func (p *EMLProvider) CreateMailbox(mailbox Mailbox) (Mailbox, error) {
+	return mailbox, nil
+}
+
+// TransferFrom imports messages from channel.
+func (p *EMLProvider) TransferFrom(rules transferRules, progress *Progress, ch <-chan Message) {
+	log.Info("Started transfer from channel to EML")
+	defer log.Info("Finished transfer from channel to EML")
+
+	err := p.createFolders(rules)
+	if err != nil {
+		progress.fatal(err)
+		return
+	}
+
+	for msg := range ch {
+		for progress.shouldStop() {
+			break
+		}
+
+		err := p.writeFile(msg)
+		progress.messageImported(msg.ID, "", err)
+	}
+}
+
+func (p *EMLProvider) createFolders(rules transferRules) error {
+	for rule := range rules.iterateActiveRules() {
+		for _, mailbox := range rule.TargetMailboxes {
+			path := filepath.Join(p.root, mailbox.Name)
+			if err := os.MkdirAll(path, os.ModePerm); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (p *EMLProvider) writeFile(msg Message) error {
+	fileName := filepath.Base(msg.ID)
+	if !strings.HasSuffix(fileName, ".eml") {
+		fileName += ".eml"
+	}
+
+	var err error
+	for _, mailbox := range msg.Targets {
+		path := filepath.Join(p.root, mailbox.Name, fileName)
+
+		if localErr := ioutil.WriteFile(path, msg.Body, 0600); localErr != nil {
+			err = multierror.Append(err, localErr)
+		}
+	}
+	return err
+}