From fe0d3b8db15dfee182392e6069c7cd70986067a6 Mon Sep 17 00:00:00 2001 From: Thomas Rothe Date: Fri, 14 Aug 2026 19:28:34 +0200 Subject: [PATCH 1/2] feat(smtp): replace CID references in HTML with attachment preview URLs --- modules/smtp/handler.go | 34 +++++++++++------ modules/smtp/handler_test.go | 72 ++++++++++++++++++++++++++++++++++++ 2 files changed, 95 insertions(+), 11 deletions(-) diff --git a/modules/smtp/handler.go b/modules/smtp/handler.go index 289812c..0daa6f9 100644 --- a/modules/smtp/handler.go +++ b/modules/smtp/handler.go @@ -114,7 +114,8 @@ func (s *session) Data(r io.Reader) error { // Generate event UUID for attachment storage. eventUUID := event.GenerateUUID() - // Store attachments. + // Store attachments and collect CID→URL mappings for inline images. + cidMap := make(map[string]string) // cid -> preview URL if s.backend.attachments != nil && len(attachments) > 0 { for _, att := range attachments { path := eventUUID + "/" + att.Filename @@ -129,6 +130,17 @@ func (s *session) Data(r io.Reader) error { attUUID, eventUUID, att.Filename, path, len(att.content), att.Type, att.ContentID, ) } + if att.ContentID != "" { + cid := strings.Trim(att.ContentID, "<>") + cidMap[cid] = "/api/smtp/attachments/" + eventUUID + "/preview/" + attUUID + } + } + } + + // Replace cid: references in HTML with attachment preview URLs. + if parsed.HTML != "" && len(cidMap) > 0 { + for cid, url := range cidMap { + parsed.HTML = strings.ReplaceAll(parsed.HTML, "cid:"+cid, url) } } @@ -167,16 +179,16 @@ type parsedAttachment struct { // ParsedEmail is the structure stored as event payload. // Field names match the original PHP Buggregator Message::jsonSerialize(). type ParsedEmail struct { - ID *string `json:"id"` - Subject string `json:"subject"` - From []EmailAddress `json:"from"` - To []EmailAddress `json:"to"` - Cc []EmailAddress `json:"cc"` - Bcc []string `json:"bcc"` - ReplyTo []EmailAddress `json:"reply_to"` - Text string `json:"text"` - HTML string `json:"html"` - Raw string `json:"raw"` + ID *string `json:"id"` + Subject string `json:"subject"` + From []EmailAddress `json:"from"` + To []EmailAddress `json:"to"` + Cc []EmailAddress `json:"cc"` + Bcc []string `json:"bcc"` + ReplyTo []EmailAddress `json:"reply_to"` + Text string `json:"text"` + HTML string `json:"html"` + Raw string `json:"raw"` } func parseEmail(raw []byte, recipients []string) (*ParsedEmail, []parsedAttachment, error) { diff --git a/modules/smtp/handler_test.go b/modules/smtp/handler_test.go index 60c7790..439d11f 100644 --- a/modules/smtp/handler_test.go +++ b/modules/smtp/handler_test.go @@ -300,6 +300,78 @@ func TestParseEmail_RFC2047Subject(t *testing.T) { } } +func TestParseEmail_InlineAttachmentWithCID(t *testing.T) { + // Build a multipart/related email with an inline image referenced via cid: + raw := []byte("From: sender@example.com\r\nTo: recipient@example.com\r\nSubject: CID Test\r\n" + + "Content-Type: multipart/related; boundary=\"rel\"\r\n\r\n" + + "--rel\r\nContent-Type: text/html\r\n\r\n" + + "\r\n" + + "--rel\r\nContent-Type: image/png\r\nContent-Disposition: inline; filename=\"logo.png\"\r\n" + + "Content-ID: \r\nContent-Transfer-Encoding: base64\r\n\r\n" + + "iVBORw0KGgo=\r\n" + + "--rel--") + + parsed, atts, err := parseEmail(raw, []string{"recipient@example.com"}) + if err != nil { + t.Fatal(err) + } + + // HTML should contain the cid: reference (replacement happens in Data(), not parseEmail). + if !strings.Contains(parsed.HTML, "cid:logo123@example.com") { + t.Errorf("HTML should still contain cid: reference, got %q", parsed.HTML) + } + + // Should have one attachment with ContentID set. + if len(atts) != 1 { + t.Fatalf("expected 1 attachment, got %d", len(atts)) + } + if atts[0].ContentID != "" { + t.Errorf("ContentID = %q, want %q", atts[0].ContentID, "") + } + if atts[0].Filename != "logo.png" { + t.Errorf("Filename = %q, want %q", atts[0].Filename, "logo.png") + } +} + +func TestReplaceCIDReferences(t *testing.T) { + // Simulate the CID replacement logic from Data(). + html := `` + cidMap := map[string]string{ + "logo@example.com": "/api/smtp/attachments/evt-uuid/preview/att-uuid-1", + "banner@example.com": "/api/smtp/attachments/evt-uuid/preview/att-uuid-2", + } + + for cid, url := range cidMap { + html = strings.ReplaceAll(html, "cid:"+cid, url) + } + + if strings.Contains(html, "cid:") { + t.Errorf("HTML still contains cid: references: %s", html) + } + if !strings.Contains(html, "/api/smtp/attachments/evt-uuid/preview/att-uuid-1") { + t.Error("missing logo preview URL") + } + if !strings.Contains(html, "/api/smtp/attachments/evt-uuid/preview/att-uuid-2") { + t.Error("missing banner preview URL") + } +} + +func TestReplaceCIDReferences_NoCID(t *testing.T) { + // When there are no CID references, HTML should remain unchanged. + html := `

No images

` + cidMap := map[string]string{} + + if len(cidMap) > 0 { + for cid, url := range cidMap { + html = strings.ReplaceAll(html, "cid:"+cid, url) + } + } + + if html != `

No images

` { + t.Errorf("HTML was modified unexpectedly: %s", html) + } +} + func TestPreviewMapper(t *testing.T) { m := &previewMapper{} From 2d414a52f7d2181bcde48ec2f7359e558cd3995c Mon Sep 17 00:00:00 2001 From: Thomas Rothe Date: Fri, 14 Aug 2026 20:53:57 +0200 Subject: [PATCH 2/2] fix(smtp): correct expected ContentID in inline attachment test parseEmail already strips angle brackets from Content-ID at parse time (handler.go:322), so the test's expected value was wrong. Co-Authored-By: Claude Sonnet 5 Claude-Session: https://claude.ai/code/session_01HTP5juELjuCdbVECrKVMSs --- modules/smtp/handler_test.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/modules/smtp/handler_test.go b/modules/smtp/handler_test.go index 439d11f..8102ce2 100644 --- a/modules/smtp/handler_test.go +++ b/modules/smtp/handler_test.go @@ -325,8 +325,8 @@ func TestParseEmail_InlineAttachmentWithCID(t *testing.T) { if len(atts) != 1 { t.Fatalf("expected 1 attachment, got %d", len(atts)) } - if atts[0].ContentID != "" { - t.Errorf("ContentID = %q, want %q", atts[0].ContentID, "") + if atts[0].ContentID != "logo123@example.com" { + t.Errorf("ContentID = %q, want %q", atts[0].ContentID, "logo123@example.com") } if atts[0].Filename != "logo.png" { t.Errorf("Filename = %q, want %q", atts[0].Filename, "logo.png")