Embedding Prerequisites

WordPress.com is built on top of the open-source WordPress publishing platform. Third-party embed markup must have a fully functional WordPress plugin with significant market interest before being considered for inclusion on WordPress.com.

WordPress Shortcode API

WordPress Shortcodes translate complex embed codes into simple macros. The WordPress publishing system, with the help of your custom plugin, converts shortcodes into the best possible markup for the requesting agent. Shortcodes help embedded content expand to the full content width of a blog theme, display different content to mobile and desktop browsers, or add specific content to web feeds. Shortcodes are the preferred embed method for WordPress sites including WordPress.com.

Example

[mysite id="abc123" fmt=22]

WordPress passes key-value attribute pairs to a shortcode plugin registered for a given shortcode name. In the example above the shortcode “mysite” receives an array with an unique identifier and format code specific to a fictional “mysite” service. The shortcode handler should recognize and verify embed customizations unique to your service. Take a look at your existing generic embed markup and define all customizations you would like a post author to configure on his or her WordPress blog.

Many WordPress themes store the width of the theme’s main content column in the content_width global variable. Shortcode handlers should be aware of the blog’s current theme and the full width available to embedded content. Post authors may want to override this default handling inside the shortcode or define the desired width of your embedded content by defining a width or height attribute (commonly abbreviated “w” and “h” in shortcode markup).

Filtering post embed content

Embed markup copy and pasted from other websites passes through WordPress HTML filters before being saved into the WordPress database. Plugins connected to the pre_kses filter can scan post content for markup better served by a WordPress Shortcode and replace the appropriate text with equivalent shortcode attributes.

Plugins should recognize customization parameters present in embed markup before converting to a shortcode. If a publisher customized an embed on your website before inserting into his or her post you should preserve such preferences inside a shortcode where supported.

Additional development notes

HTTP functions

Plugins requesting remote resources over HTTP should use the WordPress HTTP API for maximum compatibility across WordPress installations and related plugins.

PHP versions

Self-hosted WordPress requires PHP 5.2.4 or greater. WordPress.com runs PHP 5.3.

Plugin distribution

WordPress.org hosts and distributes plugins licensed under a GPLv2-compatible license. Plugins approved for distribution through WordPress.org receive access to a subversion repository, distribution through the WordPress.org website, installation and upgrade support through the WordPress administrative interface and plugin usage statistics.

WordPress.com evaluates the popularity and reported issues with existing embed plugins before considering such plugins for inclusion on WordPress.com servers.

Hired help

CodePoet is a directory of professional WordPress consultants available to assist your company and its WordPress plugin needs. Some companies post contract requests to the WordPress jobs board. WordCamp events in your area are a great way to get out and meet the WordPress community, including plugin and theme developers.