refactor smtp

smtp/session.go

@@ -0,0 +1,169 @@
+package smtp
+
+import (
+	"context"
+	"errors"
+	"io"
+
+	"github.com/emersion/go-smtp"
+	"github.com/getsentry/sentry-go"
+	"github.com/jhillyerd/enmime"
+	"gitlab.com/etke.cc/go/logger"
+	"gitlab.com/etke.cc/go/validator"
+	"maunium.net/go/mautrix/id"
+
+	"gitlab.com/etke.cc/postmoogle/utils"
+)
+
+// incomingSession represents an SMTP-submission session receiving emails from remote servers
+type incomingSession struct {
+	log          *logger.Logger
+	getRoomID    func(string) (id.RoomID, bool)
+	getFilters   func(id.RoomID) utils.IncomingFilteringOptions
+	receiveEmail func(context.Context, *utils.Email) error
+	domains      []string
+
+	ctx  context.Context
+	to   string
+	from string
+}
+
+func (s *incomingSession) Mail(from string, opts smtp.MailOptions) error {
+	sentry.GetHubFromContext(s.ctx).Scope().SetTag("from", from)
+	if !utils.AddressValid(from) {
+		return errors.New("please, provide email address")
+	}
+	s.from = from
+	s.log.Debug("mail from %s, options: %+v", from, opts)
+	return nil
+}
+
+func (s *incomingSession) Rcpt(to string) error {
+	sentry.GetHubFromContext(s.ctx).Scope().SetTag("to", to)
+	s.to = to
+	var domainok bool
+	for _, domain := range s.domains {
+		if utils.Hostname(to) == domain {
+			domainok = true
+			break
+		}
+	}
+	if !domainok {
+		s.log.Debug("wrong domain of %s", to)
+		return smtp.ErrAuthRequired
+	}
+
+	roomID, ok := s.getRoomID(utils.Mailbox(to))
+	if !ok {
+		s.log.Debug("mapping for %s not found", to)
+		return smtp.ErrAuthRequired
+	}
+
+	validations := s.getFilters(roomID)
+	if !validateEmail(s.from, s.to, s.log, validations) {
+		return smtp.ErrAuthRequired
+	}
+
+	s.log.Debug("mail to %s", to)
+	return nil
+}
+
+func (s *incomingSession) Data(r io.Reader) error {
+	parser := enmime.NewParser()
+	eml, err := parser.ReadEnvelope(r)
+	if err != nil {
+		return err
+	}
+
+	files := parseAttachments(eml.Attachments, s.log)
+
+	email := utils.NewEmail(
+		eml.GetHeader("Message-Id"),
+		eml.GetHeader("In-Reply-To"),
+		eml.GetHeader("Subject"),
+		s.from,
+		s.to,
+		eml.Text,
+		eml.HTML,
+		files)
+
+	return s.receiveEmail(s.ctx, email)
+}
+func (s *incomingSession) Reset()        {}
+func (s *incomingSession) Logout() error { return nil }
+
+// outgoingSession represents an SMTP-submission session sending emails from external scripts, using postmoogle as SMTP server
+type outgoingSession struct {
+	log      *logger.Logger
+	sendmail func(string, string, string) error
+	privkey  string
+	domains  []string
+
+	ctx  context.Context
+	to   string
+	from string
+}
+
+func (s *outgoingSession) Mail(from string, opts smtp.MailOptions) error {
+	sentry.GetHubFromContext(s.ctx).Scope().SetTag("from", from)
+	if !utils.AddressValid(from) {
+		return errors.New("please, provide email address")
+	}
+	return nil
+}
+
+func (s *outgoingSession) Rcpt(to string) error {
+	sentry.GetHubFromContext(s.ctx).Scope().SetTag("to", to)
+	s.to = to
+
+	s.log.Debug("mail to %s", to)
+	return nil
+}
+
+func (s *outgoingSession) Data(r io.Reader) error {
+	parser := enmime.NewParser()
+	eml, err := parser.ReadEnvelope(r)
+	if err != nil {
+		return err
+	}
+
+	files := parseAttachments(eml.Attachments, s.log)
+
+	email := utils.NewEmail(
+		eml.GetHeader("Message-Id"),
+		eml.GetHeader("In-Reply-To"),
+		eml.GetHeader("Subject"),
+		s.from,
+		s.to,
+		eml.Text,
+		eml.HTML,
+		files)
+
+	return s.sendmail(email.From, email.To, email.Compose(s.privkey))
+}
+func (s *outgoingSession) Reset()        {}
+func (s *outgoingSession) Logout() error { return nil }
+
+func validateEmail(from, to string, log *logger.Logger, options utils.IncomingFilteringOptions) bool {
+	enforce := validator.Enforce{
+		Email: true,
+		MX:    options.SpamcheckMX(),
+		SMTP:  options.SpamcheckMX(),
+	}
+	v := validator.New(options.Spamlist(), enforce, to, log)
+
+	return v.Email(from)
+}
+
+func parseAttachments(parts []*enmime.Part, log *logger.Logger) []*utils.File {
+	files := make([]*utils.File, 0, len(parts))
+	for _, attachment := range parts {
+		for _, err := range attachment.Errors {
+			log.Warn("attachment error: %v", err)
+		}
+		file := utils.NewFile(attachment.FileName, attachment.Content)
+		files = append(files, file)
+	}
+
+	return files
+}