Other refactor: clean old builder

internal/imap/mailbox_append.go

@@ -0,0 +1,198 @@
+// Copyright (c) 2021 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 imap
+
+import (
+	"io"
+	"net/mail"
+	"strings"
+	"time"
+
+	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	"github.com/ProtonMail/proton-bridge/internal/imap/uidplus"
+	"github.com/ProtonMail/proton-bridge/pkg/message"
+	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
+	"github.com/emersion/go-imap"
+	"github.com/pkg/errors"
+)
+
+// CreateMessage appends a new message to this mailbox. The \Recent flag will
+// be added regardless of whether flags is empty or not. If date is nil, the
+// current time will be used.
+//
+// If the Backend implements Updater, it must notify the client immediately
+// via a mailbox update.
+func (im *imapMailbox) CreateMessage(flags []string, date time.Time, body imap.Literal) error {
+	return im.logCommand(func() error {
+		return im.createMessage(flags, date, body)
+	}, "APPEND", flags, date)
+}
+
+func (im *imapMailbox) createMessage(flags []string, date time.Time, body imap.Literal) error { //nolint[funlen]
+	// Called from go-imap in goroutines - we need to handle panics for each function.
+	defer im.panicHandler.HandlePanic()
+
+	m, _, _, readers, err := message.Parse(body)
+	if err != nil {
+		return err
+	}
+
+	addr := im.storeAddress.APIAddress()
+	if addr == nil {
+		return errors.New("no available address for encryption")
+	}
+	m.AddressID = addr.ID
+
+	kr, err := im.user.client().KeyRingForAddressID(addr.ID)
+	if err != nil {
+		return err
+	}
+
+	// Handle imported messages which have no "Sender" address.
+	// This sometimes occurs with outlook which reports errors as imported emails or for drafts.
+	if m.Sender == nil {
+		im.log.Warning("Append: Missing email sender. Will use main address")
+		m.Sender = &mail.Address{
+			Name:    "",
+			Address: addr.Email,
+		}
+	}
+
+	// "Drafts" needs to call special API routes.
+	// Clients always append the whole message again and remove the old one.
+	if im.storeMailbox.LabelID() == pmapi.DraftLabel {
+		// Sender address needs to be sanitised (drafts need to match cases exactly).
+		m.Sender.Address = pmapi.ConstructAddress(m.Sender.Address, addr.Email)
+
+		draft, _, err := im.user.storeUser.CreateDraft(kr, m, readers, "", "", "")
+		if err != nil {
+			return errors.Wrap(err, "failed to create draft")
+		}
+
+		targetSeq := im.storeMailbox.GetUIDList([]string{draft.ID})
+		return uidplus.AppendResponse(im.storeMailbox.UIDValidity(), targetSeq)
+	}
+
+	// We need to make sure this is an import, and not a sent message from this account
+	// (sent messages from the account will be added by the event loop).
+	if im.storeMailbox.LabelID() == pmapi.SentLabel {
+		sanitizedSender := pmapi.SanitizeEmail(m.Sender.Address)
+
+		// Check whether this message was sent by a bridge user.
+		user, err := im.user.backend.bridge.GetUser(sanitizedSender)
+		if err == nil && user.ID() == im.storeUser.UserID() {
+			logEntry := im.log.WithField("addr", sanitizedSender).WithField("extID", m.Header.Get("Message-Id"))
+
+			// If we find the message in the store already, we can skip importing it.
+			if foundUID := im.storeMailbox.GetUIDByHeader(&m.Header); foundUID != uint32(0) {
+				logEntry.Info("Ignoring APPEND of duplicate to Sent folder")
+				return uidplus.AppendResponse(im.storeMailbox.UIDValidity(), &uidplus.OrderedSeq{foundUID})
+			}
+
+			// We didn't find the message in the store, so we are currently sending it.
+			logEntry.WithField("time", date).Info("No matching UID, continuing APPEND to Sent")
+		}
+	}
+
+	message.ParseFlags(m, flags)
+	if !date.IsZero() {
+		m.Time = date.Unix()
+	}
+
+	internalID := m.Header.Get("X-Pm-Internal-Id")
+	references := m.Header.Get("References")
+	referenceList := strings.Fields(references)
+
+	// In case there is a mail client which corrupts headers, try
+	// "References" too.
+	if internalID == "" && len(referenceList) > 0 {
+		lastReference := referenceList[len(referenceList)-1]
+		match := pmapi.RxInternalReferenceFormat.FindStringSubmatch(lastReference)
+		if len(match) == 2 {
+			internalID = match[1]
+		}
+	}
+
+	im.user.appendExpungeLock.Lock()
+	defer im.user.appendExpungeLock.Unlock()
+
+	// Avoid appending a message which is already on the server. Apply the
+	// new label instead. This always happens with Outlook (it uses APPEND
+	// instead of COPY).
+	if internalID != "" {
+		// Check to see if this belongs to a different address in split mode or another ProtonMail account.
+		msg, err := im.storeMailbox.GetMessage(internalID)
+		if err == nil && (im.user.user.IsCombinedAddressMode() || (im.storeAddress.AddressID() == msg.Message().AddressID)) {
+			IDs := []string{internalID}
+
+			// See the comment bellow.
+			if msg.IsMarkedDeleted() {
+				if err := im.storeMailbox.MarkMessagesUndeleted(IDs); err != nil {
+					log.WithError(err).Error("Failed to undelete re-imported internal message")
+				}
+			}
+
+			err = im.storeMailbox.LabelMessages(IDs)
+			if err != nil {
+				return err
+			}
+
+			targetSeq := im.storeMailbox.GetUIDList(IDs)
+			return uidplus.AppendResponse(im.storeMailbox.UIDValidity(), targetSeq)
+		}
+	}
+
+	im.log.Info("Importing external message")
+	if err := im.importMessage(m, readers, kr); err != nil {
+		im.log.Error("Import failed: ", err)
+		return err
+	}
+
+	// IMAP clients can move message to local folder (setting \Deleted flag)
+	// and then move it back (IMAP client does not remember the message,
+	// so instead removing the flag it imports duplicate message).
+	// Regular IMAP server would keep the message twice and later EXPUNGE would
+	// not delete the message (EXPUNGE would delete the original message and
+	// the new duplicate one would stay). API detects duplicates; therefore
+	// we need to remove \Deleted flag if IMAP client re-imports.
+	msg, err := im.storeMailbox.GetMessage(m.ID)
+	if err == nil && msg.IsMarkedDeleted() {
+		if err := im.storeMailbox.MarkMessagesUndeleted([]string{m.ID}); err != nil {
+			log.WithError(err).Error("Failed to undelete re-imported message")
+		}
+	}
+
+	targetSeq := im.storeMailbox.GetUIDList([]string{m.ID})
+	return uidplus.AppendResponse(im.storeMailbox.UIDValidity(), targetSeq)
+}
+
+func (im *imapMailbox) importMessage(m *pmapi.Message, readers []io.Reader, kr *crypto.KeyRing) (err error) {
+	body, err := message.BuildEncrypted(m, readers, kr)
+	if err != nil {
+		return err
+	}
+
+	labels := []string{}
+	for _, l := range m.LabelIDs {
+		if l == pmapi.StarredLabel {
+			labels = append(labels, pmapi.StarredLabel)
+		}
+	}
+
+	return im.storeMailbox.ImportMessage(m, body, labels)
+}