Extensions

An extension is a plugin that ships inside Riff. Each one lives in this repository as a plugin of its own, under plugins/<name>/, with its own header, version and tests, and uses Riff only through its public hooks and APIs (Hooks, JavaScript), as anyone's plugin would. Riff Lyrics is the first.

How one is bundled

plugins/riff/extensions.json names them:

{
	"extensions": [ "riff-lyrics" ]
}

A release builds Riff with .github/scripts/build-riff.sh, which copies each one named into riff/extensions/<name>/, through .distignore, as it copies Riff, and moves its strings into Riff's riff text domain, since WordPress.org translates a plugin under its own slug alone; its handles, keys and classes keep their names. Every workflow that builds or deploys Riff uses that script. A checkout of the repository has no extensions/ folder, and Riff finds each extension beside it, in plugins/<name>/, so nothing is kept twice.

Riff Sign In is never an extension. It is installed on its own, by whoever runs the site.

How Riff loads one

As WordPress loads plugins, before plugins_loaded, Riff loads each extension's main file, <name>/<name>.php, unless:

• it is off, on Settings › Riff, or for the whole network on Network Admin › Settings › Riff, where a network admin can lock it for every site;
• it is installed and active as its own plugin, which WordPress loads instead;
• its Requires Riff header names a newer Riff than this one.

The riff_extensions filter changes the list: a host can leave one out, or name a plugin it has placed in Riff's extensions/ folder.

Writing one

Write a plugin, with a Requires Riff header naming the oldest Riff whose hooks it uses. Its main file returns at once if it has already been loaded, so a copy activated as its own plugin while Riff's is running doesn't load it twice:

if ( defined( 'MY_EXTENSION_VERSION' ) ) {
	return;
}
define( 'MY_EXTENSION_VERSION', '1.0.0' );

Anything else it needs comes from its own folder (__FILE__, plugin_dir_url( __FILE__ )), which works wherever it is installed. To ship it inside Riff, add its folder under plugins/ and its name to extensions.json.