youtube oembed for playlist link

[alexufo]

i think better add youtube playlist for auto embeding.
​http://www.youtube.com/playlist?list=PL6BCB25412319E08A

This code must add to class-oembed.php providers. I think playlist id lenth is 18.

'#http:\/\/(www\.)?youtube\.com\/playlist\?list=.{18}#i'    => array( 'http://www.youtube.com/oembed', true  ),

and... why "/" are not escaping in class-oembed.php providers?

[wonderboymusic]

In 28552:

Support oEmbed matching for YouTube playlist URLs.

Fixes #28125.

[SergeyBiryukov]

and... why "/" are not escaping in class-oembed.php providers?

It only needs escaping if it's used as a delimiter in the same expression. We use # as a delimiter here.

[kovshenin]

Has anybody considered, that every time we change the regex/pattern in any of the existing items in the oEmbed providers list, we're breaking backwards compatibility for sites that use wp_oembed_remove_provider(), for example to disallow YouTube embeds?

[wonderboymusic]

In 28593:

For YouTube playlist oEmbed, we need keep BC for wp_oembed_remove_provider() by not changing the existing YouTube endpoint keys. So, rather than merging the rules, the playlist endpoints should be on their own line.

Props kovshenin.

See #28125, [28552].

[nacin]

Replying to kovshenin:

Has anybody considered, that every time we change the regex/pattern in any of the existing items in the oEmbed providers list, we're breaking backwards compatibility for sites that use wp_oembed_remove_provider(), for example to disallow YouTube embeds?

I've not considered this. I'm OK with [28593] but I wouldn't consider this precedent-setting. We've changed patterns before and probably will have a need to in the future.

[kovshenin]

Re r28593, I wasn't implying that every new variation/addition to an embed handler should be a regex of its own, that's actually worse, because the regex engine now has to parse, cache and execute four expressions instead of two. The reason I asked about backwards compatibility is whether perhaps we should be looking at keying the list by a unique handle instead of a regular expression.

[Viper007Bond]

Replying to kovshenin:

perhaps we should be looking at keying the list by a unique handle instead of a regular expression.

Sounds like a good idea to me. That's how the non-oEmbed callback embed handlers work.