Wiki

Hi All,

Reading through this thread, this appears to be a pretty vexed issue that has not yet gone away! It certainly appears to be the case that in Moodle 2.0(.1) YouTube videos are handled differently inside a wiki to the way they are handled in a course topic or similar general location.

In a course topic the whole object/embed content (or even the iframe) copied from youtube's embed panel can be pasted into the html editor, saved and displayed as a video. This object takes its size and settings from the copied code, and so even 3D glasses options will work INSIDE moodle without the need to link out.

Of course, you cannot paste such content in at all if object/embed code is specifically outlawed in...

Admin -> Security -> Site Policies    'Allow EMBED and OBJECT tags' = No

unless also in the same site policies 'Enable trusted content' = Yes,

AND the user's role settings say their content will be trusted!

More strictly, you can paste it in, but you find it remove or deactivated. But aside from these permissions issues, this embedding method of getting youtube content into a topic works a treat!

In the wiki, however, we do not seem to be playing by the same rules! This may well be forced onto the situation by the notion of the wiki being a collaborative activity (generally speaking), so if you can't 'trust' the content from one user, how can you trust the content from another! If this is the view taken, which seems likely, then object/embed & iframe entries pose a security risk (or at least the risk of unacceptable content), and these get removed even if you are a trusted being! So what about using other possible routes?

Yes, you can enable the Multimedia plugin filter for youtube videos and that works consistantly inside and outside a wiki. As we know, this means that if you enter some text, highlight it, click the hyperlink button, and then paste in the url of the video. Such as:  youtube.com/watch?v=0GcLW0g_c1s. Note however, that this url needs to be take from youtube's 'share' panel, not the 'embed panel' because they are quite different. The 'share' version works with the filter, whereas the embed version youtube.com/embed/0GcLW0g_c1s does not! This is simply because the filter is looking for ?v= in the url, and in the latter version it isn't gong to find it! [note I've had to cut the http etc to stop this link linking!!!]

So for moodle to behave consistantly we need to be consistant too. And there is obviously room for confusion here.

There is also a method involving the use of a [youtube] tag each side of the url, as explained here: http://docs.moodle.org/en/Multimedia_plugins#YouTube_Link_Filter

but I'm still not clear as to how that is different from simply using the media filter described above.

However, the multimedia filter may solve one problem, but it creates another. Elsewhere it has been explained that you can change the size of the display in some types of media by trailing it with d=400x300 (or similar), but the youtube instance of the filter strips these out. in fact it strips out all the content after the ? except the v=#### video reference. This means that using the multimedia filter to give youtube content results in a loss of control of the size of the video in the wiki, and leaves out all the options (such as the colour of your 3D glasses)!

So we appear to have away to go on this as yet.

Regards,

John

Having thought about this a bit more, I think Franco's solution above may work but will have unintended consequences (such as switching off filtering you want left on).

So I have set about finding a fix for the underlying problems.

Firstly, not being able to supply dimensions to the youtube filter the way you can to Quicktime or Flash video. This only really requires a few changes to the file /filter/mediaplugin/filter.php

We find the line

if (!empty($CFG->filter_mediaplugin_enable_youtube)) {

and make changes as highlighted (copy and paste, but only in a proper HTML editor, eg Smultron, Fraise, Ultraedit)

if (!empty($CFG->filter_mediaplugin_enable_youtube)) {
//see MDL-23903 for description of recent changes to this regex
//$search = '/<a.*?href="([^<]*)youtube.com\/watch\?v=([^"]*)"[^>]*>(.*?)<\/a>/is';
$search = '/<a[^>]*href="([^<]*?)youtube.com\/watch\?v=([^&"]*)(&amp;d=([\d]{1,3}%?)x([\d]{1,3}%?))?"[^>]*>(.*?)<\/a>/is';
$newtext = preg_replace_callback($search, 'filter_mediaplugin_youtube_callback', $newtext);
$search = '/<a[^>]*href="([^<]*)youtube.com\/v\/([^"\?]*)(\?d=([\d]{1,3}%?)x([\d]{1,3}%?))?"[^>]*>(.*?)<\/a>/is';
$newtext = preg_replace_callback($search, 'filter_mediaplugin_youtube_callback', $newtext);
}

Then we find the callback function filter_mediaplugin_youtube_callback and make these changes...

function filter_mediaplugin_youtube_callback($link, $autostart=false) {

$site = addslashes_js($link[1]);
$url = addslashes_js($link[2]);
$info = addslashes_js(strip_tags($link[3]));//strip out html tags as they won't work in the title attribute
if (empty($link[4]) or empty($link[5])) {
$size = 'width="425" height="344"';
} else {
$size = 'width="'.$link[4].'" height="'.$link[5].'"';
}

return '<object title="'.$info.'"
class="mediaplugin mediaplugin_youtube" type="application/x-shockwave-flash"
data="'.$site.'youtube.com/v/'.$url.'&amp;fs=1&amp;rel=0" '.$size.'>'.
'<param name="movie" value="'.$site.'youtube.com/v/'.$url.'&amp;fs=1&amp;rel=0" />'.
'<param name="FlashVars" value="playerMode=embedded" />'.
'<param name="wmode" value="transparent" />'.
'<param name="allowFullScreen" value="true" />'.
'</object>';
}

This should allow dimensions to but put in either in the form

http:// www .youtube.com/watch?v=6RFuRY7azgA&d=450x300

or

http:// www .youtube.com/v/6RFuRY7azgA?d=450x300

Note thank this depends entirely on the url you get from 'share' in youtube!

Finally we can also get Moodle to do the work on putting in an iframe that users are generally blocked from (along with object and embed). My reasoning here is that it must be safe for moodle to do in the say way as it embeds to object safely for you!

Here we add an extra trap in the filtering process inside the same braces as before (top of this post)

$search = '/<a[^>]*href="([^<]*)youtube.com\/embed\/([^"\?]*)(\?d=([\d]{1,3}%?)x([\d]{1,3}%?))?"[^>]*>(.*?)<\/a>/is';
$newtext = preg_replace_callback($search, 'filter_mediaplugin_youtube_embed_callback', $newtext);

Note this adds a NEW function call so them we add a new callback function (below the current youtube one)

/**
* Change links to embedding Youtube content into iframe Youtube videos
*/
function filter_mediaplugin_youtube_embed_callback($link, $autostart=false) {

$site = addslashes_js($link[1]);
$url = addslashes_js($link[2]);
$info = addslashes_js(strip_tags($link[3]));//strip out html tags as they won't work in the title attribute
if (empty($link[4]) or empty($link[5])) {
$size = 'width="640" height="390"';
} else {
$size = 'width="'.$link[4].'" height="'.$link[5].'"';
}

return '<iframe title="YouTube video player" class="youtube-player" type="text/html" '.
'src="'.$site.'youtube.com/embed/'.$url.'" '.
'frameborder="0" '.$size.'>'.
'</iframe>';
}

And THIS allows you to use the youtube embed content, BUT WITHOUT THE IFRAME STUFF ARROUND IT. Like so:

http:// www .youtube.com/embed/6RFuRY7azgA

And add dimensions, like so:

http:// www .youtube.com/embed/6RFuRY7azgA?d=640x390

I've tested this moderately well though only on Firefox.

Thats all for now.

John

[note: I have inserted a couple of spaces in urls to stop them linking! - there must be a better way?]

Yes! Thank you! This helped me! I have been adding videos to a wiki that my pupils have been creating about our lessons. The first one was added as a simple link (to the video file uploaded in the file area of the course) and it worked! But then any subsequent links were not showing. Disabling the Camel Case links works wonders-I can now see all videos!

Phew! I was getting a bit worried when seeing all the technical changes mentioned in the previous posts. Thanks Ruth!