Allows MediaWiki to force purge for anonymous requests, with ?action=purge&forcepurge=1. This is intended to be used when generating links webcrawlers shouldn't get.

ForcePurgeAction

diff --git a/includes/actions/PurgeAction.php b/includes/actions/PurgeAction.php
index cd58889..5a8cc6f 100644
--- a/includes/actions/PurgeAction.php
+++ b/includes/actions/PurgeAction.php
@@ -61,7 +61,8 @@ class PurgeAction extends FormAction {
                // This will throw exceptions if there's a problem
                $this->checkCanExecute( $this->getUser() );

-               if ( $this->getUser()->isAllowed( 'purge' ) ) {
+               $forcePurge = isset( $_GET['forcepurge'] ) && ( $_GET['forcepurge'] == 1 );
+               if ( $forcePurge || $this->getUser()->isAllowed( 'purge' ) ) {
                        $this->redirectParams = wfArrayToCGI( array_diff_key(
                                $this->getRequest()->getQueryValues(),
                                array( 'title' => null, 'action' => null )