Creating a WordPress Plugin

Over the past couple of months we’ve started to look at creating functions and using actions and filters in our functions.php theme file to help manipulate the content output by WordPress. If you create something and feel it’s worthy of releasing for others to use then rather than just posting the code up for others to copy, it’s usually better to write a plugin.

To start a plugin file off you use a PHP comment to contain the information about the plugin. This is:

< ?php
/*
Plugin Name: Put your plugin name here
Plugin URI: http://www.yourdomain.com/path-to-plugin-page/
Description: Plugin description here
Version: 1.0
Author: Your Name
Author URI: http://www.yourdomain.com
*/
?>

The above tells WordPress information about your plugin and this is the information that gets displayed on the plugins page in the admin section.

After this you can then add your functions and hooks/filters if needed. If we take the simple function we first looked at, to output social bookmarking links, then we would simply add the function below the comments eg.

<?php
/*
Plugin Name: Output Social Bookmarks
Plugin URI: http://www.bloggingtips.com/wordpress-plugins/social-bookmarks/
Description: Displays Social Bookmarks for the current post.
Version: 1.0
Author: SarahG
Author URI: http://www.bloggingtips.com
*/
function display_sblinks($cssid = "social") {
global $post;
?>
<ul id="<?php echo $cssid ?>">
<li>Bookmark this page at: </li>
<li><a href="http://del.icio.us/post?url=<?php the_permalink() ?>&amp;title=<?php echo urlencode(the_title('','',FALSE)); ?>" title="Bookmark <?php the_title() ?> on Del.icio.us">Del.icio.us</a> - </li>
<li><a href="http://www.stumbleupon.com/submit?url=<?php the_permalink() ?>&amp;title=<?php echo urlencode(the_title('','',FALSE)); ?>" title="Submit <?php the_title() ?> to StumbleUpon">StumbleUpon</a> - </li>
<li><a href="http://www.spurl.net/spurl.php?url=<?php the_permalink() ?>&amp;title=<?php echo urlencode(the_title('','',FALSE)); ?>" title="Bookmark <?php the_title() ?> on Spurl">Spurl</a></li>
</ul>
<?php
}
?>

You would save this as a standard PHP file and then put it in your plugins directory. When you then go into the plugins page you’ll see it as an unactivated plugin ie. just like any other plugin you’ve added to your site.

Next week I’ll explain how to give more flexibility and control over your plugins with an options page.

Written by Sarah from Stuff By Sarah
Posted on March 15th, 2009 and filed under WordPress Coding & Design
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