ProcessPreview.module

<?php

/**
 * ProcessPreview
 *
 * (c) 2014 Nico Knoll (http://www.nico-knoll.de/)
 *
 * Sponsored by dreizunull.com
 *
 */

class ProcessPreview extends Process implements Module {

	public static function getModuleInfo() {
		return array(
			'title' => 'Preview', 
			'version' => '2.5.0', 
			'summary' => 'Let you see a preview of a page.',
			'singular' => true, 
			'autoload' => true 
		);
	}

	public function init() {
		parent::init();
		$this->addHook('ProcessPageEdit::buildForm', $this, 'addButton');
		$this->addHook('ProcessPageView::execute', $this, 'changeView');

		// if ajax Request
		if($this->input->get->ajax == 'true') {
			echo $this->ajaxPreviewToSession();
			exit;
		}
	}

	private function ajaxPreviewToSession() {
		// get the data into $data
		foreach($this->input->post as $key => $value) {
			$data[$key] = $value;
		}

		// set field stuff into session so the opened page can use it
		$this->session->set('preview', $data);

		// retrurn the pages preview url
		$previewURL = $this->pages->get($this->input->get->id)->url.'?preview=true';
		return $previewURL;
	}

	public function changeView(HookEvent $event) {
		// get session data
		$sessionData = $this->session->get('preview');

		// check if ?preview=true
		if($this->input->get->preview != 'true') return false;

		// check if the opened page is the one we created the preview for
		$page = $this->page;
		if($this->page->id != $sessionData['id']) return false;

		// abort if NullPage
		if($page instanceof NullPage) return false;
		// abort request if page is not editable
		if(!$page->editable()) return;

		// replace field content of the $page var with the preview stuff saved in the session
		foreach($sessionData as $key => $value) {
			if($page->fields->has($key)) $page->setFieldValue($key, $value);
		}

		$page->status = Page::statusOn;

		// return the preview merged page
		$event->return = $page->setOutputFormatting(true)->render();

		// reset preview session
		$this->session->remove('preview');
	}


	public function addButton(HookEvent $event) {
		// it's better to go with hleper to prevent include automatically on every page becaue of autoload
		$this->config->styles->add($this->config->urls->ProcessPreview.'ProcessPreviewHelper.css');
		$this->config->scripts->add($this->config->urls->ProcessPreview.'ProcessPreviewHelper.js');

		// generate the link / button ...
		$field = $this->modules->get('InputfieldButton');
		$field->attr('id+name', 'previewButton'); 
		$field->attr('class', $field->class);
		$field->attr('target', '_blank');
		$field->attr('value', $this->_('Preview')); 

		// little hacking to add the preview link as link and not as button
		$href = $this->pages->get($this->input->get->id)->url.'?preview=true&time='.time();
		$wrapper = $this->modules->get('InputfieldMarkup');
		$wrapper->attr('id+name', 'previewMarkupWrapper');
		$wrapper->attr('value', '</div></li>
		<li class="Inputfield InputfieldPreview Inputfield_previewButton InputfieldColumnWidthFirst" id="wrap_previewButton">
			<div class="InputfieldContent">

				<a href="'.$href.'" class="ui-button ui-widget ui-corner-all head_button_clone ui-state-default" id="previewButton" target="_blank">
					<span class="ui-button-text">'.$this->_('Preview').'</span>
				</a>

		');

		// ... and add it to the form
		$event->return = $event->return->append($wrapper); 
	}


}