clear output buffer before xml responses to prevent whitespace

[ps2602]

Clear output buffer before xml responses to prevent whitespace or other extraneous characters from being sent.

[westi]

What is the bug you are trying to fix here?

[ps2602]

For some reason, there are a quite a few plugins that output white space which breaks xml parsing in all browsers. I keep coming across this problem in both ms-files.php and now the send method of the WP_Ajax_Response class so I just added ob_clean to the method in order to prevent plugins from being able to inadvertently break functionality in wordpress. I read up on ticket #14730 and I understand the viewpoint that ob_clean should not be used to cover the mistakes of plugin authors. However, finding unnecessary output in a plugin and contacting the author every time I come across this issue (which seems to happen often) seems counter-productive when users can be protected from such mistakes with a one-liner.

[nacin]

This would affect more than just WP_Ajax_Response and ms-files.php. It would also affect all RSS feeds too.

I'm not convinced this is a good idea. We can only hold the hands of plugin authors so much.

[bpetty]

This is indeed a bug in the respective plugins and themes triggering this.

I also think that the most likely cause of issues like this is due to use of EOF ?> on PHP files, which has also since been dropped entirely in core in r19712, after this ticket was opened, and probably dropped in a ton of plugins by now too.

Since there's been no interest in this for nearly 2 years now too, I'm closing this out. Re-open if you think this is still a valid concern.