Why bother with an entire plugin when you can just add a few lines to your theme’s functions.php file and use a WordPress hook to filter the feed content?

function my_rss_footer($content) {
if (is_feed()) {
$content .= '<p><small>&copy;WP Fix, all rights reserved.</small></p>';
}
return $content;
}

add_action('the_content', 'my_rss_footer');

The the_content filter fires when a page is loaded in WordPress. We use the is_feed() conditional to tell WordPress to only add the footer if the page being generated is an RSS feed.

Note that we use $content .= and not $content = when setting the footer text. This means that the text will be added to the end of $content, which is the post content, rather than replacing it entirely.

The screencast covers the basic file structure of plugins, and how to work with hooks and filters. In short, the two essentials. The example plugin that you will be walked-through the making of is a stripped-down version of the plugin that the screencaster wrote to aid him in his editing work for Net.Tuts+. It fixes HTML in posts to be in the preferred format. (H3s instead of H2s, images wrapped in a DIV with a certain class, etc.)

Overall, the 40-minute (approx.) video is a good introduction to WordPress plugin development.

What if you’re interested in plugin development, but you don’t know PHP? Another Envato blog, that of the ThemeForest marketplace, has a nice series of screencasts on the language.

Here’s some code:

curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $twitter_data);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_USERPWD, "{$twitter_user}:{$twitter_password}");