Allow KnowledgableExtractorJS to parse out youtube watch from youtube…

[vonrosen]

… javascript embed

[nlevitt]

Hey Hunter, looking at https://developers.google.com/youtube/iframe_api_reference?hl=en
their sample code has

    <!-- 1. The <iframe> (and video player) will replace this <div> tag. -->
    <div id="player"></div>

    function onYouTubeIframeAPIReady() {
        player = new YT.Player('player', {
          height: '390',
          width: '640',
          videoId: 'M7lc1UVf-VE',
          events: {
            'onReady': onPlayerReady,
            'onStateChange': onPlayerStateChange
          }
        });
      }

The first argument to YT.Player is an html tag id, which is arbitrary. Your regex only checks for 'ytplayer' though. Best to allow anything there.

Also, the regex should probably accept either single-quotes or double-quotes (right now it looks only for single-quotes).

Separately, it would be good to use addRelativeToBase(). Here's my suggested, untested code:

            String newUri = "https://www.youtube.com/watch?v=" + videoId;
            try {
                addRelativeToBase(curi,
                        ext.getExtractorParameters().getMaxOutlinks(), newUri,
                        LinkContext.INFERRED_MISC, Hop.INFERRED);
            } catch (URIException e) {
                // no way this should happen
                throw new IllegalStateException(newUri, e);
            }