GODT-1141 Use attachment name from content type if not specified in content disposition

pkg/message/parser.go

@@ -503,12 +503,15 @@ func parseAttachment(h message.Header) (*pmapi.Attachment, error) {
 	}
 	att.Header = mimeHeader
 
-	mimeType, _, err := h.ContentType()
+	mimeType, mimeTypeParams, err := h.ContentType()
 	if err != nil {
 		return nil, err
 	}
 	att.MIMEType = mimeType
 
+	// Prefer attachment name from filename param in content disposition.
+	// If not available, try to get it from name param in content type.
+	// Otherwise fallback to attachment.bin.
 	_, dispParams, dispErr := h.ContentDisposition()
 	if dispErr != nil {
 		ext, err := mime.ExtensionsByType(att.MIMEType)
@@ -521,10 +524,12 @@ func parseAttachment(h message.Header) (*pmapi.Attachment, error) {
 		}
 	} else {
 		att.Name = dispParams["filename"]
-
-		if att.Name == "" {
-			att.Name = "attachment.bin"
-		}
+	}
+	if att.Name == "" {
+		att.Name = mimeTypeParams["name"]
+	}
+	if att.Name == "" {
+		att.Name = "attachment.bin"
 	}
 
 	// Only set ContentID if it should be inline;

pkg/message/parser_test.go

@@ -239,6 +239,24 @@ func TestParseTextPlainWithOctetAttachmentBadFilename(t *testing.T) {
 	assert.Equal(t, "attachment.bin", m.Attachments[0].Name)
 }
 
+func TestParseTextPlainWithOctetAttachmentNameInContentType(t *testing.T) {
+	f := getFileReader("text_plain_octet_attachment_name_in_contenttype.eml")
+
+	m, _, _, _, err := Parse(f) //nolint[dogsled]
+	require.NoError(t, err)
+
+	assert.Equal(t, "attachment-contenttype.txt", m.Attachments[0].Name)
+}
+
+func TestParseTextPlainWithOctetAttachmentNameConflict(t *testing.T) {
+	f := getFileReader("text_plain_octet_attachment_name_conflict.eml")
+
+	m, _, _, _, err := Parse(f) //nolint[dogsled]
+	require.NoError(t, err)
+
+	assert.Equal(t, "attachment-disposition.txt", m.Attachments[0].Name)
+}
+
 func TestParseTextPlainWithPlainAttachment(t *testing.T) {
 	f := getFileReader("text_plain_plain_attachment.eml")
 

pkg/message/testdata/text_plain_octet_attachment_name_conflict.eml

@@ -0,0 +1,14 @@
+From: Sender <sender@pm.me>
+To: Receiver <receiver@pm.me>
+Content-Type: multipart/mixed; boundary=longrandomstring
+
+--longrandomstring
+
+body
+--longrandomstring
+Content-Type: application/octet-stream; name="attachment-contenttype.txt"
+Content-Transfer-Encoding: base64
+Content-Disposition: attachment; filename="attachment-disposition.txt"
+
+aWYgeW91IGFyZSByZWFkaW5nIHRoaXMsIGhpIQ==
+--longrandomstring--

pkg/message/testdata/text_plain_octet_attachment_name_in_contenttype.eml

@@ -0,0 +1,14 @@
+From: Sender <sender@pm.me>
+To: Receiver <receiver@pm.me>
+Content-Type: multipart/mixed; boundary=longrandomstring
+
+--longrandomstring
+
+body
+--longrandomstring
+Content-Type: application/octet-stream; name="attachment-contenttype.txt"
+Content-Transfer-Encoding: base64
+Content-Disposition: attachment
+
+aWYgeW91IGFyZSByZWFkaW5nIHRoaXMsIGhpIQ==
+--longrandomstring--