<?php
/*
* Copyright (C) 2008 Anis uddin Ahmad <anisniit@gmail.com>
* Copyright (C) 2010-2012 Michael Bemmerl <mail@mx-server.de>
*
* This file is part of the "Universal Feed Writer" project.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// RSS 0.90 Officially obsoleted by 1.0
// RSS 0.91, 0.92, 0.93 and 0.94 Officially obsoleted by 2.0
// So, define constants for RSS 1.0, RSS 2.0 and ATOM
define('RSS1', 'RSS 1.0', true);
define('RSS2', 'RSS 2.0', true);
define('ATOM', 'ATOM', true);
if (!class_exists('FeedItem'))
require dirname(__FILE__) . '/FeedItem.php';
/**
* Universal Feed Writer class
*
* Generate RSS 1.0, RSS2.0 and ATOM Feeds
*
* @package UniversalFeedWriter
* @author Anis uddin Ahmad <anisniit@gmail.com>
* @link http://www.ajaxray.com/projects/rss
*/
abstract class FeedWriter
{
private $channels = array(); // Collection of channel elements
private $items = array(); // Collection of items as object of FeedItem class.
private $data = array(); // Store some other version wise data
private $CDATAEncoding = array(); // The tag names which have to encoded as CDATA
private $version = null;
/**
* Constructor
*
* @param constant the version constant (RSS1/RSS2/ATOM).
*/
protected function __construct($version = RSS2)
{
$this->version = $version;
// Setting default value for essential channel elements
$this->channels['title'] = $version . ' Feed';
$this->channels['link'] = 'http://www.ajaxray.com/blog';
//Tag names to encode in CDATA
$this->CDATAEncoding = array('description', 'content:encoded', 'summary');
}
// Start # public functions ---------------------------------------------
/**
* Set a channel element
* @access public
* @param string name of the channel tag
* @param string content of the channel tag
* @return void
*/
public function setChannelElement($elementName, $content)
{
$this->channels[$elementName] = $content;
}
/**
* Set multiple channel elements from an array. Array elements
* should be 'channelName' => 'channelContent' format.
*
* @access public
* @param array array of channels
* @return void
*/
public function setChannelElementsFromArray($elementArray)
{
if (!is_array($elementArray))
return;
foreach ($elementArray as $elementName => $content)
{
$this->setChannelElement($elementName, $content);
}
}
/**
* Genarate the actual RSS/ATOM file
*
* @access public
* @param bool FALSE if the specific feed media type should be send.
* @return void
*/
public function generateFeed($useGenericContentType = FALSE)
{
$contentType = "text/xml";
if (!$useGenericContentType)
{
switch($this->version)
{
case RSS2 : $contentType = "application/rss+xml";
break;
case RSS1 : $contentType = "application/rdf+xml";
break;
case ATOM : $contentType = "application/atom+xml";
break;
}
}
header("Content-Type: " . $contentType . "; charset=UTF-8");
$this->printHeader();
$this->printChannels();
$this->printItems();
$this->printFooter();
}
/**
* Create a new FeedItem.
*
* @access public
* @return object instance of FeedItem class
*/
public function createNewItem()
{
$Item = new FeedItem($this->version);
return $Item;
}
/**
* Add a FeedItem to the main class
*
* @access public
* @param object instance of FeedItem class
* @return void
*/
public function addItem(FeedItem $feedItem)
{
if ($feedItem->getVersion() != $this->version)
die('Feed type mismatch: This instance can handle ' . $this->version . ' feeds only, but item with type ' . $feedItem->getVersion() . ' given.');
$this->items[] = $feedItem;
}
// Wrapper functions -------------------------------------------------------------------
/**
* Set the 'title' channel element
*
* @access public
* @param string value of 'title' channel tag
* @return void
*/
public function setTitle($title)
{
$this->setChannelElement('title', $title);
}
/**
* Set the 'updated' channel element of an ATOM feed
*
* @access public
* @param string value of 'updated' channel tag
* @return void
*/
public function setDate($date)
{
if ($this->version != ATOM)
return;
if ($date instanceof DateTime)
$date = $date->format(DateTime::ATOM);
else if(is_numeric($date))
$date = date(DATE_ATOM, $date);
else
$date = date(DATE_ATOM, strtotime($date));
$this->setChannelElement('updated', $date);
}
/**
* Set the 'description' channel element
*
* @access public
* @param string value of 'description' channel tag
* @return void
*/
public function setDescription($desciption)
{
if ($this->version != ATOM)
$this->setChannelElement('description', $desciption);
}
/**
* Set the 'link' channel element
*
* @access public
* @param string value of 'link' channel tag
* @return void
*/
public function setLink($link)
{
$this->setChannelElement('link', $link);
}
/**
* Set the 'image' channel element
*
* @access public
* @param string title of image
* @param string link url of the image
* @param string path url of the image
* @return void
*/
public function setImage($title, $link, $url)
{
$this->setChannelElement('image', array('title'=>$title, 'link'=>$link, 'url'=>$url));
}
/**
* Set the 'about' channel element. Only for RSS 1.0
*
* @access public
* @param string value of 'about' channel tag
* @return void
*/
public function setChannelAbout($url)
{
$this->data['ChannelAbout'] = $url;
}
/**
* Generates an UUID
* @author Anis uddin Ahmad <admin@ajaxray.com>
* @param string an optional prefix
* @return string the formated uuid
*/
public static function uuid($key = null, $prefix = '')
{
$key = ($key == null)? uniqid(rand()) : $key;
$chars = md5($key);
$uuid = substr($chars,0,8) . '-';
$uuid .= substr($chars,8,4) . '-';
$uuid .= substr($chars,12,4) . '-';
$uuid .= substr($chars,16,4) . '-';
$uuid .= substr($chars,20,12);
return $prefix . $uuid;
}
// End # public functions ----------------------------------------------
// Start # private functions ----------------------------------------------
/**
* Prints the xml and rss namespace
*
* @access private
* @return void
*/
private function printHeader()
{
$out = '<?xml version="1.0" encoding="utf-8"?>' . PHP_EOL;
if($this->version == RSS2)
{
$out .= '<rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/">';
}
elseif($this->version == RSS1)
{
$out .= '<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://purl.org/rss/1.0/" xmlns:dc="http://purl.org/dc/elements/1.1/">';
}
else if($this->version == ATOM)
{
$out .= '<feed xmlns="http://www.w3.org/2005/Atom">';
}
$out .= PHP_EOL;
echo $out;
}
/**
* Closes the open tags at the end of file
*
* @access private
* @return void
*/
private function printFooter()
{
if($this->version == RSS2)
{
echo '</channel>' . PHP_EOL . '</rss>';
}
elseif($this->version == RSS1)
{
echo '</rdf:RDF>';
}
else if($this->version == ATOM)
{
echo '</feed>';
}
}
/**
* Creates a single node as xml format
*
* @access private
* @param string name of the tag
* @param mixed tag value as string or array of nested tags in 'tagName' => 'tagValue' format
* @param array Attributes(if any) in 'attrName' => 'attrValue' format
* @return string formatted xml tag
*/
private function makeNode($tagName, $tagContent, $attributes = null)
{
$nodeText = '';
$attrText = '';
if(is_array($attributes) && count($attributes) > 0)
{
foreach ($attributes as $key => $value)
{
$value = htmlspecialchars($value);
$attrText .= " $key=\"$value\" ";
}
// Get rid of the last whitespace
$attrText = substr($attrText, 0, strlen($attrText) - 1);
}
if(is_array($tagContent) && $this->version == RSS1)
{
$attrText = ' rdf:parseType="Resource"';
}
$attrText .= (in_array($tagName, $this->CDATAEncoding) && $this->version == ATOM) ? ' type="html"' : '';
$nodeText .= "<{$tagName}{$attrText}>";
$nodeText .= (in_array($tagName, $this->CDATAEncoding)) ? '<![CDATA[' : '';
if(is_array($tagContent))
{
foreach ($tagContent as $key => $value)
{
$nodeText .= $this->makeNode($key, $value);
}
}
else
{
$nodeText .= (in_array($tagName, $this->CDATAEncoding))? $this->sanitizeCDATA($tagContent) : htmlspecialchars($tagContent);
}
$nodeText .= (in_array($tagName, $this->CDATAEncoding)) ? ']]>' : '';
$nodeText .= "</$tagName>" . PHP_EOL;
return $nodeText;
}
/**
* @desc Print channels
* @access private
* @return void
*/
private function printChannels()
{
//Start channel tag
switch ($this->version)
{
case RSS2:
echo '<channel>' . PHP_EOL;
break;
case RSS1:
echo (isset($this->data['ChannelAbout']))? "<channel rdf:about=\"{$this->data['ChannelAbout']}\">" : "<channel rdf:about=\"{$this->channels['link']}\">";
break;
}
//Print Items of channel
foreach ($this->channels as $key => $value)
{
if($this->version == ATOM && $key == 'link')
{
// ATOM prints link element as href attribute
echo $this->makeNode($key,'', array('href' => $value));
//Add the id for ATOM
echo $this->makeNode('id', FeedWriter::uuid($value, 'urn:uuid:'));
}
else
{
echo $this->makeNode($key, $value);
}
}
//RSS 1.0 have special tag <rdf:Seq> with channel
if($this->version == RSS1)
{
echo "<items>" . PHP_EOL . "<rdf:Seq>" . PHP_EOL;
foreach ($this->items as $item)
{
$thisItems = $item->getElements();
echo "<rdf:li resource=\"{$thisItems['link']['content']}\"/>" . PHP_EOL;
}
echo "</rdf:Seq>" . PHP_EOL . "</items>" . PHP_EOL . "</channel>" . PHP_EOL;
}
}
/**
* Prints formatted feed items
*
* @access private
* @return void
*/
private function printItems()
{
foreach ($this->items as $item)
{
$thisItems = $item->getElements();
//the argument is printed as rdf:about attribute of item in rss 1.0
echo $this->startItem($thisItems['link']['content']);
foreach ($thisItems as $feedItem)
{
echo $this->makeNode($feedItem['name'], $feedItem['content'], $feedItem['attributes']);
}
echo $this->endItem();
}
}
/**
* Make the starting tag of channels
*
* @access private
* @param string The vale of about tag which is used for RSS 1.0 only.
* @return void
*/
private function startItem($about = false)
{
if($this->version == RSS2)
{
echo '<item>' . PHP_EOL;
}
else if($this->version == RSS1)
{
if($about)
{
echo "<item rdf:about=\"$about\">" . PHP_EOL;
}
else
{
die("link element is not set." . PHP_EOL . "It's required for RSS 1.0 to be used as the about attribute of the item tag.");
}
}
else if($this->version == ATOM)
{
echo "<entry>" . PHP_EOL;
}
}
/**
* Closes feed item tag
*
* @access private
* @return void
*/
private function endItem()
{
if($this->version == RSS2 || $this->version == RSS1)
{
echo '</item>' . PHP_EOL;
}
else if($this->version == ATOM)
{
echo "</entry>" . PHP_EOL;
}
}
/**
* Sanitizes data which will be later on returned as CDATA in the feed.
*
* A "]]>" respectively "<![CDATA" in the data would break the CDATA in the
* XML, so the brackets are converted to a HTML entity.
*
* @access private
* @param string Data to be sanitized
* @return string Sanitized data
*/
private function sanitizeCDATA($text)
{
$text = str_replace("]]>", "]]>", $text);
$text = str_replace("<![CDATA[", "<![CDATA[", $text);
return $text;
}
// End # private functions ----------------------------------------------
} // end of class FeedWriter