extension.driver.php

<?php
// file extensions/resave_entries/extension.driver.php

class extension_resave_entries extends Extension
{
	public function about()
	{
		return array(
			'name' => 'Resave entries',
			'version' => '0.1',
			'release-date' => '2011-06-03',
			'author' => array(
				'name' => 'Marco Sampellegrini',
				'email' => 'm@rcosa.mp'
			)
		);
	}
	
	public function getSubscribedDelegates()
	{
		return array(
			array(
				'page' => '/system/preferences/',
				'delegate' => 'AddCustomPreferenceFieldsets',
				'callback' => 'AddCustomPreferenceFieldsets',
			)
		);
	}

	public function AddCustomPreferenceFieldsets($context)
	{
		if (isset($_POST['action']['resave']))
		{
			$id = $_POST['resave-section'];
			require_once TOOLKIT. '/class.entrymanager.php';
			$engine = Symphony::Engine();
			

			$em = new EntryManager($engine);
			$sm = new SectionManager($engine);
			$fm = new FieldManager($engine);
			$ex = new ExtensionManager($engine);

			$entries = $em->fetch($entry_id = null, $id);
			$fields  = $fm->fetch($field_id = null, $id);
			$section = $sm->fetch($id);
			
			if (!empty($entries)) $entries[0]->checkPostData(array());

			foreach ($entries as $e)
			{
				$e->commit();
				$ex->notifyMembers('EntryPostEdit', '/publish/edit/', array('section' => $section, 'entry' => $e, 'fields' => $fields));
			}
			
			Administration::instance()->Page->pageAlert(__('Entries resaved succesfully.'), Alert::SUCCESS);
		}
		
		$group = new XMLElement('fieldset');
		$group->setAttribute('class', 'settings');
		$group->appendChild(new XMLElement('legend', __('Resave entries'))); 
		
		$span = new XMLElement('span', NULL, array('class' => 'frame'));
		
		require_once TOOLKIT. '/class.sectionmanager.php';
		$sm = new SectionManager(Symphony::Engine());
		$sections = $sm->fetch();

		$options = array();
		foreach ($sections as $s)
		{
			$options[] = array(
				$s->get('id'), false, $s->get('name')
			);
		}
		
		$select = Widget::Select('resave-section', $options);
		$span->appendChild($select);
		$span->appendChild(new XMLElement('button', __('Resave Entries'), array_merge(array('name' => 'action[resave]', 'type' => 'submit'))));

		$group->appendChild($span);
		$context['wrapper']->appendChild($group);
	}
}

Nice! You should probably also add the EntryPreRender and EntryPreEdit delegates too, in case these manipulate the Entry objects.

Batching could follow my Search Index, whereby it fires an AJAX request passing a page and per-page number. These entries are processed, and if there are more entries (the total-pages is less than the page parameter that is passed) then more AJAX requests are made. But this is a neat proof of concept :-)

Thanks Nick, ajax sounds like a good idea. Will implement this soon :)

Awesome Marco! This will complement so many other extensions, including one I'm working on :-)