plugin custom code to install another plugin
// Include required libs for installation
require_once( ABSPATH . 'wp-admin/includes/plugin-install.php' );
require_once( ABSPATH . 'wp-admin/includes/class-wp-upgrader.php' );
require_once( ABSPATH . 'wp-admin/includes/class-wp-ajax-upgrader-skin.php' );
require_once( ABSPATH . 'wp-admin/includes/class-plugin-upgrader.php' );
// Get Plugin Info
$api = plugins_api( 'plugin_information',
array(
'slug' => $plugin,
'fields' => array(
'short_description' => false,
'sections' => false,
'requires' => false,
'rating' => false,
'ratings' => false,
'downloaded' => false,
'last_updated' => false,
'added' => false,
'tags' => false,
'compatibility' => false,
'homepage' => false,
'donate_link' => false,
),
)
);
$skin = new WP_Ajax_Upgrader_Skin();
$upgrader = new Plugin_Upgrader( $skin );
$upgrader->install( $api->download_link );