add !pm autoreply

README.md

@@ -36,6 +36,7 @@ so you can use it to send emails from your apps and scripts as well.
 - [x] Send a message to matrix room with special format to send a new email, even to multiple email addresses at once
 - [x] Reply to matrix thread sends reply into email thread
 - [x] Email signatures
+- [x] Email autoreply / autoresponder for new email threads
 
 ## Configuration
 
@@ -121,6 +122,7 @@ If you want to change them - check available options in the help message (`!pm h
 
 > The following section is visible to the mailbox owners only
 
+* **`!pm autoreply`** - Get or set autoreply of the room (markdown supported) that will be sent on any new incoming email thread
 * **`!pm signature`** - Get or set signature of the room (markdown supported)
 * **`!pm nosend`** - Get or set `nosend` of the room (`true` - disable email sending; `false` - enable email sending)
 * **`!pm noreplies`** - Get or set `noreplies` of the room (`true` - ignore matrix replies; `false` - parse matrix replies)

bot/command.go

@@ -99,6 +99,12 @@ func (b *Bot) initCommands() commandList {
 			allowed:     b.allowOwner,
 		},
 		{allowed: b.allowOwner, description: "mailbox options"}, // delimiter
+		{
+			key:         config.RoomAutoreply,
+			description: "Get or set autoreply of the room (markdown supported) that will be send for any new incoming email thread",
+			sanitizer:   func(s string) string { return s },
+			allowed:     b.allowOwner,
+		},
 		{
 			key:         config.RoomSignature,
 			description: "Get or set signature of the room (markdown supported)",

bot/command_owner.go

@@ -119,7 +119,8 @@ func (b *Bot) setOption(ctx context.Context, name, value string) {
 		}
 	}
 
-	if name == config.RoomSignature {
+	if name == config.RoomAutoreply ||
+		name == config.RoomSignature {
 		value = strings.Join(b.parseCommand(evt.Content.AsMessage().Body, false)[1:], " ")
 	}
 

bot/config/room.go

@@ -18,22 +18,26 @@ const (
 	RoomOwner     = "owner"
 	RoomMailbox   = "mailbox"
 	RoomDomain    = "domain"
-	RoomNoSend        = "nosend"
-	RoomNoReplies     = "noreplies"
-	RoomNoCC          = "nocc"
-	RoomNoSender      = "nosender"
-	RoomNoRecipient   = "norecipient"
-	RoomNoSubject     = "nosubject"
-	RoomNoHTML        = "nohtml"
-	RoomNoThreads     = "nothreads"
-	RoomNoFiles       = "nofiles"
-	RoomNoInlines     = "noinlines"
 	RoomPassword  = "password"
 	RoomSignature = "signature"
+	RoomAutoreply = "autoreply"
+
+	RoomNoCC        = "nocc"
+	RoomNoFiles     = "nofiles"
+	RoomNoHTML      = "nohtml"
+	RoomNoInlines   = "noinlines"
+	RoomNoRecipient = "norecipient"
+	RoomNoReplies   = "noreplies"
+	RoomNoSend      = "nosend"
+	RoomNoSender    = "nosender"
+	RoomNoSubject   = "nosubject"
+	RoomNoThreads   = "nothreads"
+
 	RoomSpamcheckDKIM = "spamcheck:dkim"
+	RoomSpamcheckMX   = "spamcheck:mx"
 	RoomSpamcheckSMTP = "spamcheck:smtp"
 	RoomSpamcheckSPF  = "spamcheck:spf"
-	RoomSpamcheckMX   = "spamcheck:mx"
+
 	RoomSpamlist = "spamlist"
 )
 
@@ -71,6 +75,10 @@ func (s Room) Signature() string {
 	return s.Get(RoomSignature)
 }
 
+func (s Room) Autoreply() string {
+	return s.Get(RoomAutoreply)
+}
+
 func (s Room) NoSend() bool {
 	return utils.Bool(s.Get(RoomNoSend))
 }

bot/email.go

@@ -111,6 +111,8 @@ func (b *Bot) GetIFOptions(roomID id.RoomID) email.IncomingFilteringOptions {
 }
 
 // IncomingEmail sends incoming email to matrix room
+//
+//nolint:gocognit // TODO
 func (b *Bot) IncomingEmail(ctx context.Context, email *email.Email) error {
 	roomID, ok := b.GetMapping(email.Mailbox(true))
 	if !ok {
@@ -125,9 +127,11 @@ func (b *Bot) IncomingEmail(ctx context.Context, email *email.Email) error {
 	defer b.mu.Unlock(roomID.String())
 
 	var threadID id.EventID
+	newThread := true
 	if email.InReplyTo != "" || email.References != "" {
 		threadID = b.getThreadID(roomID, email.InReplyTo, email.References)
 		if threadID != "" {
+			newThread = false
 			b.setThreadID(roomID, email.MessageID, threadID)
 		}
 	}
@@ -138,6 +142,7 @@ func (b *Bot) IncomingEmail(ctx context.Context, email *email.Email) error {
 			return utils.UnwrapError(serr)
 		}
 		threadID = "" // unknown event edge case - remove existing thread ID to avoid complications
+		newThread = true
 	}
 	if threadID == "" {
 		threadID = eventID
@@ -154,18 +159,103 @@ func (b *Bot) IncomingEmail(ctx context.Context, email *email.Email) error {
 		b.sendFiles(ctx, roomID, email.Files, cfg.NoThreads(), threadID)
 	}
 
+	if newThread && cfg.Autoreply() != "" {
+		b.sendAutoreply(roomID, threadID)
+	}
+
 	return nil
 }
 
+//nolint:gocognit // TODO
+func (b *Bot) sendAutoreply(roomID id.RoomID, threadID id.EventID) {
+	cfg, err := b.cfg.GetRoom(roomID)
+	if err != nil {
+		return
+	}
+
+	text := cfg.Autoreply()
+	if text == "" {
+		return
+	}
+
+	evt := &event.Event{
+		ID:     threadID + "-autoreply",
+		RoomID: roomID,
+		Content: event.Content{
+			Parsed: &event.MessageEventContent{
+				RelatesTo: &event.RelatesTo{
+					Type:    event.RelThread,
+					EventID: threadID,
+				},
+			},
+		},
+	}
+
+	meta := b.getParentEmail(evt, cfg.Mailbox())
+
+	if meta.To == "" {
+		return
+	}
+
+	if meta.ThreadID == "" {
+		meta.ThreadID = threadID
+	}
+	if meta.Subject == "" {
+		meta.Subject = "Automatic response"
+	}
+	content := format.RenderMarkdown(text, true, true)
+	signature := format.RenderMarkdown(cfg.Signature(), true, true)
+	body := content.Body
+	if signature.Body != "" {
+		body += "\n\n---\n" + signature.Body
+	}
+	var htmlBody string
+	if !cfg.NoHTML() {
+		htmlBody = content.FormattedBody
+		if htmlBody != "" && signature.FormattedBody != "" {
+			htmlBody += "<br><hr><br>" + signature.FormattedBody
+		}
+	}
+
+	meta.MessageID = email.MessageID(evt.ID, meta.FromDomain)
+	meta.References = meta.References + " " + meta.MessageID
+	b.log.Info().Any("meta", meta).Msg("sending automatic reply")
+	eml := email.New(meta.MessageID, meta.InReplyTo, meta.References, meta.Subject, meta.From, meta.To, meta.RcptTo, meta.CC, body, htmlBody, nil, nil)
+	data := eml.Compose(b.cfg.GetBot().DKIMPrivateKey())
+	if data == "" {
+		return
+	}
+
+	var queued bool
+	ctx := newContext(evt)
+	recipients := meta.Recipients
+	for _, to := range recipients {
+		queued, err = b.Sendmail(evt.ID, meta.From, to, data)
+		if queued {
+			b.log.Info().Err(err).Str("from", meta.From).Str("to", to).Msg("email has been queued")
+			b.saveSentMetadata(ctx, queued, meta.ThreadID, recipients, eml, cfg, "Autoreply has been sent (queued)")
+			continue
+		}
+
+		if err != nil {
+			b.Error(ctx, evt.RoomID, "cannot send email: %v", err)
+			continue
+		}
+	}
+
+	b.saveSentMetadata(ctx, queued, meta.ThreadID, recipients, eml, cfg, "Autoreply has been sent")
+}
+
+func (b *Bot) canReply(sender id.UserID, roomID id.RoomID) bool {
+	return b.allowSend(sender, roomID) && b.allowReply(sender, roomID)
+}
+
 // SendEmailReply sends replies from matrix thread to email thread
 //
 //nolint:gocognit // TODO
 func (b *Bot) SendEmailReply(ctx context.Context) {
 	evt := eventFromContext(ctx)
-	if !b.allowSend(evt.Sender, evt.RoomID) {
-		return
-	}
-	if !b.allowReply(evt.Sender, evt.RoomID) {
+	if !b.canReply(evt.Sender, evt.RoomID) {
 		return
 	}
 	cfg, err := b.cfg.GetRoom(evt.RoomID)
@@ -399,12 +489,15 @@ func (b *Bot) getParentEmail(evt *event.Event, newFromMailbox string) *parentEma
 
 // saveSentMetadata used to save metadata from !pm sent and thread reply events to a separate notice message
 // because that metadata is needed to determine email thread relations
-func (b *Bot) saveSentMetadata(ctx context.Context, queued bool, threadID id.EventID, recipients []string, eml *email.Email, cfg config.Room) {
+func (b *Bot) saveSentMetadata(ctx context.Context, queued bool, threadID id.EventID, recipients []string, eml *email.Email, cfg config.Room, textOverride ...string) {
 	addrs := strings.Join(recipients, ", ")
 	text := "Email has been sent to " + addrs
 	if queued {
 		text = "Email to " + addrs + " has been queued"
 	}
+	if len(textOverride) > 0 {
+		text = textOverride[0]
+	}
 
 	evt := eventFromContext(ctx)
 	content := eml.Content(threadID, cfg.ContentOptions())