First try at a ProcessWire module to convert a PageArray to JSON

PagesToJSON

<?php

/**
 * ProcessWire PagesToJSON Module
 *
 * Adds the ability to output a PageArray as JSON
 * Original code from RC here: http://processwire.com/talk/topic/1417-export-array-to-json-format/
 * Don't for get to add header("Content-type: application/json"); to pages that output JSON only
 * 
 * ProcessWire 2.x 
 * Copyright (C) 2011 by Ryan Cramer 
 * Licensed under GNU/GPL v2, see LICENSE.TXT
 * 
 * http://www.processwire.com
 * http://www.ryancramer.com
 *
 */

class PagesToJSON extends WireData implements Module {


	public static function getModuleInfo() {
		return array(
			'title' => __('Pages to JSON', __FILE__), // Module Title
			'summary' => __('Adds the ability to output a PageArray as JSON.', __FILE__), // Module Summary
			'version' => 101, 
			'permanent' => true, 
			'singular' => true, 
			'autoload' => true, 
			);
	}

	protected $config; 

	/**
	 * Initialize the hooks
	 *
	 */
	public function init() {
		$this->config = $this->fuel('config'); 
		$this->addHook('Pages::toJSON', $this, 'pagesToJSON');
	}

	/**
	 * Return a string with all of the Page data in the PageArray encoded as JSON
	 *
	 *
	 * @return string JSON formatted data
	 *
	 */
	public function pagesToJSON($event) {
 
		$pages = $event->object; 

		$a = array();
		foreach($pages as $page) {
			$a[] = pageToArray($page); 
		}
		
		$event->return = json_encode($a); 		
	}



	/**
	 * Return an array with the standard PW fields and a nested data array of all custom Page template fields
	 *
	 *
	 * @return array the Page object as an array
	 *
	 */
	protected function pageToArray(Page $page) {

		$outputFormatting = $page->outputFormatting;
		$page->setOutputFormatting(false);

		$data = array(
	        'id' => $page->id,
	        'parent_id' => $page->parent_id,
	        'templates_id' => $page->templates_id,
	        'name' => $page->name,
	        'status' => $page->status,
	        'sort' => $page->sort,
	        'sortfield' => $page->sortfield,
	        'numChildren' => $page->numChildren,
	        'template' => $page->template->name,
	        'parent' => $page->parent->path,
	        'data' => array(),
	    );

	  	foreach($page->template->fieldgroup as $field) {
	  		if($field->type instanceof FieldtypeFieldsetOpen) continue;
	        	$value = $page->get($field->name); 
	        	$data['data'][$field->name] = $field->type->sleepValue($page, $field, $value);
	  	}

	  	$page->setOutputFormatting($outputFormatting);

	  	return $data;
	}

}