A couple of days ago, I’ve been asked how to make Sliding Notes work in sidebar widgets. The general answer is, as with any shortcode: “Enable shortcodes in widgets”.
As it turns out, finding out how to do it right is not nearly as easy as it should be, due to some tricky interweavement with plug-in loading and execution order.
The Punchline
Most advice on this converges to this simple line of code:
add_filter('widget_text', 'do_shortcode');
Though a wide spread method, this is not quite correct. The more correct way would be:
if (!is_admin()) add_filter('widget_text', 'do_shortcode', 11);
That is, (a) process shortcodes only if outside the admin area, and (b) process them at priority 11, where they belong.
BTW: Ideally, the code should even read
if (!is_admin()) add_filter('widget_text', 'do_shortcode', SHORTCODE_PRIORITY);
to avoid guessing what the number 11 means, but SHORTCODE_PRIORITY is a constant the WordPress team has yet to provide.
Update: The place to insert the above code is not arbitrary. Many WordPress functions don’t work as expected when WordPress initialization has not reached a certain point.
It is safest to put the code in a plugin.
The Widget Tweaks Composer, a free online tool for WordPress, can create a plugin for you that does the trick, and more.
The Background
Shortcode processing is a WordPress filter – one out of several filters applied when WordPress renders the page HTML, many of which stem from various plug-ins.
The above code, however, adds shortcode processing at the default priority of 10. This is different to the shortcode priority in posts, which is 11.
This means, some filters may be executed before, some after the do_shortcode filter. Should there be filters that execute with both, content and widgets, it may very well happen that the output in widgets is different then the output in posts. (Depending on plug-ins used, and their loading order, the issue may or may not manifest.)
To illustrate the situation, imagine two plug-ins, one implementing a shortcode, the other implementing a filter. The filter is running at default priority 10, and checks if a particular shortcode (or any other pattern of text for that matter) is present in the content.
In posts, the filter would see the shortcode, because it has not been processed yet. In widgets, it may as well not see it, if the filter plug-in is loaded after the shortcode plug-in.1 Hence, the overall result is likely to be different in widgets, then it is in posts.
- The WordPress plug-in load order is one of the bigger mysteries in the universe
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October 11th, 2009 at 2:46 pm
Hi – I landed on your page looking for a way to “shortcode” a widget without coding another template or plugin. It turns out what I wanted was kinda the other way round I think from what you are talking about….
I wanted to use a widget as a shortcode…. and so a trial version of “shortcode_any_widget” was born. I thought I’d post a comment here in case other readers were looking for a similar thing. I hope that’s okay? See
http://webdesign.anmari.com/shortcode-any-widget/
October 14th, 2009 at 10:23 am
Anmari, sure it’s okay. (I understand when you try to use my blog to promote yours
)
A nice idea BTW!
October 17th, 2009 at 2:40 am
I added the correct code to my functions.php but my ics-calendar shortcode (and others) won’t be executed.. any ideas?
October 18th, 2009 at 10:59 am
Lasse, functions.php may not be the right place to do it. It is because many WP functions (including conditional tags like
is_admin) don’t work as expected unless WP initialization has reached a certain point. I use a small plugin for this kind of tasks.January 12th, 2010 at 7:51 pm
Can you explain what you ment by putting it in a plugin?
January 13th, 2010 at 7:40 pm
Yoav, you could put that code into a theme file, your wp-config.php, or a plugin. I consider the last to be the best way. Actually, meanwhile there exists a plugin that does things like that in a very optimal way: My WordPress Tweaks Bundle. Put together your own tweaks with my Wordpress Tweaks Composer.
January 13th, 2010 at 9:08 pm
Hi Hachadelic.yes, i used your Tweak widget and it worked.thank you.
January 17th, 2010 at 6:15 pm
Hello
Maybe you can help me with this : I added a text widget with a shortcode to a function I wrote, basically it calls an include file which displays a div on the page.
But the div doesn’t appear inside the text widget div, but before the widget div.
Example :
contents
empty
instead of
<contents
Is there a way to fix this?
thanks
January 17th, 2010 at 7:59 pm
Paul I’m afraid the comment editor ate your tags. Please use entities (“<” => “<”, “> => “<”).
January 29th, 2010 at 12:11 am
What if a shortcode hacks the way other shortcodes are loaded, such as embed? See:
http://phpdoc.wordpress.org/tr....._shortcode
January 29th, 2010 at 12:35 am
In this case, what is needed is:
add_filter( ‘widget_text’, array(&$wp_embed, ‘run_shortcode’), 8 );
January 31st, 2010 at 11:14 am
gilek7, thanks for the hint. Since they disable other shortcodes during run_shortcode(), you’ll have to have both run_shortcode and do_shortcode in place in order to make [embed] available in widgets alongside with other shortcodes.
March 12th, 2010 at 8:34 am
Any idea why this is not working on my end? Using WP 2.9.2 with inFocus premium theme (however it doesn’t work when I revert back to Kubrick either). I’m trying to use [audio] (MP3 Audio Player plugin) which works fine in a post but not in the text widget. I’ve tried adding the filter to functions.php, then the Hackadelic plugin method, but nothing works.
March 14th, 2010 at 9:32 am
Saul, I don’t know the plugin. However, your issue looks like the plugin doesn’t use the shortcode API, but the filter API to emulate a shortcode (perhaps because there’s been no shortcode API when the plugin was first created). Another plugin, WPaudio MP3 Player, seems to be widget-enabled though, so you might want to switch.
April 13th, 2010 at 6:11 pm
Thanks for the tip man, I was actually looking for a hook on which I could run the ‘the_content’ filter on text widgets to get all its effects, but now that I think of it really I just wanted shortcode support so this works great (and you pointed out the right filter anyway). Glad to learn about the priority considerations as well. Keep up the god work, I love your slogan
April 14th, 2010 at 9:49 am
Jeremy, you are welcome.
April 27th, 2010 at 5:26 am
Will this do anything different than just calling do_shortcode($content)
http://codex.wordpress.org/Fun....._shortcode
April 28th, 2010 at 7:13 am
Andrew,
do_shortcode($content)on widget content? Any widget content? Doesn’t make much sense outside theme code, does it?July 27th, 2010 at 1:45 am
Do you know of any way to utilize shortcodes in theme options text areas? Thank you in advance.
July 27th, 2010 at 12:24 pm
Jason, yes, I know, and even you are basically a “competitor” of mine, I’ll tell you nonetheless.
The way I do it is to pass the option through do_shortcode right after obtaining it from the database.