oEmbed: Newlines within <pre> tags get removed

[cweiske]

An oEmbed's HTML content gets all \n newlines removed through

add_filter( 'oembed_dataparse', array($this, '_strip_newlines'), 10, 3 );

WP_oEmbed::strip_newlines() unfortunately removes every newline, even those within <pre> tags - but they are crucial there. My oEmbedded code pastes all only have a single line currently: ​http://fotostore.cweiske.de/screenshots/2015-02-02%20wordpress%20oembed%20newlines.png

Please fix this method to not remove newlines within <pre> tags.

[wonderboymusic]

31214.diff​ does this if DOMDocument exists, which falls in line with other places that bow out if DOMDocument isn't available (please don't disable this, for crying out loud).

The tokens have to be sequential to account for HTML nodes that may be identical

[wonderboymusic]

In 31415:

Protect <pre> tags when parsing oEmbed responses in WP_oEmbed::_strip_newlines() in DOMDocument is available.

Fixes #31214.

[wonderboymusic]

In 31416:

After [31415], make sure str_replace() only occurs once for each matched tag to avoid overwriting until <pre>s.

See #31214.

[cweiske]

The applied patch does not work when the <pre> tag contains HTML entities like  .

$dom->saveHTML() replaces the entities with their real characters, which in turn leads to a failing following str_replace call.

Try to embed ​http://p.cweiske.de/158 - it is what I have the problem with.

[cweiske]

I tried to use html_entity_decode on the input HTML and the saveHTML()'ed HTML, but it seems that the saved <pre> tag is UTF-8, while the input html is a different encoding.

[wonderboymusic]

it's the DOMDocument internals, trying a few different things now...

[wonderboymusic]

1. DOMDocument is awesome and completely sucks at the same time
2. 31214.2.diff​ uses RegEx instead, please test.

[cweiske]

Thanks - this patch works fine.

​http://fotostore.cweiske.de/screenshots/2015-02-11%20wordpress%20phorkie%20oembed%20fixed.png

[wonderboymusic]

In 31423:

Use RegEx instead of DOMDocument when protecting <pre> tags in WP_oEmbed::_strip_newlines(). It is incredibly difficult to maintain character encoding and whitespace when parsing via DOMDocument.

See #31214.

[wonderboymusic]

Calling this fixed - I have been filtering oembed responses for 3 weeks now and adding <pre> tags. All works as expected.