Problem with _drupal_wrap_mail_line and attachment files

I'm experiencing a similar issue with a custom email form that uses the Upload element module to upload a file to send as an attachment.

Sending a docx file does not work (a .txt file containing hieroglyphics is received), apparently because of the lengthy name for the mime type. In my case, commenting out this line in the _drupal_wrap_mail_line function in includes/mail.inc allows the attachment to be sent properly:

$line = wordwrap($line, 77 - $values['length'], $values['soft'] ? "  \n" : "\n");

I've run into this issue today. Using Contact Attach like MaxMendez. The docx content type is being split even to three lines!

--b4a452e28855b54e258a93b65aeb7b87
Content-Type:  
application/vnd.openxmlformats-officedocument.wordprocessingml.document;  
name="hello.docx"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="hello.docx"

UEsDBBQABgAIAAAAIQApwh5lnAEAABIGAAATAAgCW0NvbnRlbnRfVHlwZXNdLnhtbCCiBAIooAAC
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
...
--b4a452e28855b54e258a93b65aeb7b87--

It seems that Drupal mail isn't designed to handle multipart messages. I've tried several approaches to fix it, but there is no easy way out of this - except the solution considered by brianbrarian which means we resign on wrapping the text of the e-mail.

Note that I'm using strpos instead of preg_match since the benchmark showed me +36% perfomance gain.

$line = "LKGELKGMLKEMGLEKGMLKENGLEKGN";
$max = 1000000;

$start = microtime(TRUE);
for ($i = 1; $i < $max; ++$i) {
  $line_is_mime_header = strpos($line, 'Content-Type: ') === 0
    || strpos($line, 'Content-Transfer-Encoding: ') === 0
    || strpos($line, 'Content-Disposition: ') === 0
    || strpos($line, 'Content-Description: ') === 0;
}
$strpos = microtime(TRUE) - $start;
dvm($strpos, 'strpos:');

$start = microtime(TRUE);
for ($i = 1; $i < $max; ++$i) {
  preg_match('/^(Content-Type|Content-Transfer-Encoding|Content-Disposition|Content-Description): /', $line);
}
$preg_match = microtime(TRUE) - $start;
dvm($preg_match, 'preg_match:');

dvm(number_format(($preg_match - $strpos) / $preg_match * 100) . '%');

Lets fix this in D8 first.

Can anyone give me a hint on how to test this without a contrib module? Is there a way to attach stuff in core?

I agree that this should fixed in core, I just don't know how to test this.

Added a unit test for drupal_wrap_mail() to prove that the fix does the trick. There is no way to send mails with attachments from the UI without contrib modules, so this can't be tested easily as a functional test.
Patch without wojtha's fix is supposed to fail.

Without a contrib module, this can't be fully tested, but the patch and test look good.

Great. In that case I'm re-rolling #6 to convert the test to comply with PSR-0, as other system tests in D8 are now converted to comply with PSR-0.

+++ b/core/includes/mail.incundefined
@@ -513,10 +513,23 @@ function drupal_html_to_text($string, $allowed_tags = NULL) {
+  $line_is_mime_header = strpos($line, 'Content-Type: ') === 0 || strpos($line, 'Content-Transfer-Encoding: ') === 0 || strpos($line, 'Content-Disposition: ') === 0 || strpos($line, 'Content-Description: ') === 0;
+  if (!$line_is_mime_header) {

I wonder if we could re-write this against an array of headers? That would make it easier to modify later if we run across others with problems.

+++ b/core/modules/system/lib/Drupal/system/Tests/Mail/WrapMailUnitTest.phpundefined
@@ -0,0 +1,42 @@
+  function testDrupalWrapMail() {

Just need a quick line of PHPDoc on top of this function.

Hi,
Will this be fixed in Drupal 7?

I wonder if we could re-write this against an array of headers? That would make it easier to modify later if we run across others with problems. -webchick

Sure. It will be less performant but more readable.

Just need a quick line of PHPDoc on top of this function. -webchick

Added.

Back to webchick for consideration :)

Looks like webchick has this.

Awesome, thanks!

Committed and pushed to 8.x.

Back to 7.x for porting.

Great, it's a merry christmas after all!

Here's the D7 version. There shouldn't be any problems in backporting this.

#18: D7-mail-dont-wrap-mime-lines-1328696-18.patch queued for re-testing.

#18: D7-mail-dont-wrap-mime-lines-1328696-18.patch queued for re-testing.

Unrelated fail. Can't be because of this patch.

#18: D7-mail-dont-wrap-mime-lines-1328696-18.patch queued for re-testing.

18: D7-mail-dont-wrap-mime-lines-1328696-18.patch queued for re-testing.

Re-rolled.

Fixed test.

Did anyone bother to put this into D7? Having a patch is ok, but not having to patch D7 is even better. I highly doubt this patch would still be valid for current D7 dev or stable.

Tested and looks like patch in #26 needs re-roll for Drupal 7.77

Attached is patch from comment #26 re-rolled against Drupal 7.77 and since we don't have a use for it maybe someone who does might test it and comment back. Thanks.

The re-roll in #33 appears to apply to stock 7.77 on my end.

The patch still passes tests on latest Drupal 7.x branch.

See also #1447236: DefaultMailSystem implements MailSystemInterface::format() incorrectly, which changes the same function changed in this patch. Whichever patch gets committed first, the other one needs to be re-rolled.