FeedWriter.php

<?php
// 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');
define('RSS2', 'RSS 2.0');
define('ATOM', 'ATOM');

/**
 * Univarsel Feed Writer class
 *
 * Genarate RSS 1.0, RSS2.0 and ATOM Feed
 *
 * @package     UnivarselFeedWriter
 * @author      Anis uddin Ahmad <anisniit@gmail.com>
 * @link        http://www.ajaxray.com/projects/rss
 */
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 $version constant the version constant (RSS1/RSS2/ATOM).
     */
    function __construct($version = RSS2)
    {
        $this->version = $version;

        // Setting default value for assential 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', 'title');
    }

    // Start # public functions ---------------------------------------------

    /**
     * Set multiple channel elements from an array. Array elements
     * should be 'channelName' => 'channelContent' format.
     *
     * @param $elementArray array array of channels
     * @return void
     */
    public function setChannelElementsFromArray($elementArray)
    {
        if (!is_array($elementArray)) return;
        foreach ($elementArray as $elementName => $content) {
            $this->setChannelElement($elementName, $content);
        }
    }

    /**
     * Set a channel element
     *
     * @param $elementName string name of the channel tag
     * @param $content string  content of the channel tag
     * @return void
     */
    public function setChannelElement($elementName, $content)
    {
        $this->channels[$elementName] = $content;
    }

    /**
     * Genarate the actual RSS/ATOM file
     *
     * @return void
     */
    public function generateFeed()
    {
//		header("Content-type: text/xml");

        $this->printHead();
        $this->printChannels();
        $this->printItems();
        $this->printTale();
    }

    /**
     * Prints the xml and rss namespace
     *
     * @access   private
     * @return   void
     */
    private function printHead()
    {
        $out = '<?xml version="1.0" encoding="utf-8"?>' . "\n";

        if ($this->version == RSS2) {
            $out .= '<rss version="2.0"
					xmlns:content="http://purl.org/rss/1.0/modules/content/"
					xmlns:wfw="http://wellformedweb.org/CommentAPI/"
					xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
				  >' . PHP_EOL;
        } elseif ($this->version == RSS1) {
            $out .= '<rdf:RDF
					 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
					 xmlns="http://purl.org/rss/1.0/"
					 xmlns:dc="http://purl.org/dc/elements/1.1/"
					>' . PHP_EOL;;
        } else if ($this->version == ATOM) {
            $out .= '<feed xmlns="http://www.w3.org/2005/Atom">' . PHP_EOL;;
        }
        echo $out;
    }

    /**
     * @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', $this->uuid($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;
        }
    }


    // Wrapper functions -------------------------------------------------------------------

    /**
     * Creates a single node as xml format
     *
     * @access   private
     * @param    srting  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($attributes)) {
            foreach ($attributes as $key => $value) {
                $attrText .= " $key=\"$value\" ";
            }
        }

        if (is_array($tagContent) && $this->version == RSS1) {
            $attrText = ' rdf:parseType="Resource"';
        }


        $attrText .= (in_array($tagName, $this->CDATAEncoding) && $this->version == ATOM) ? ' type="html" ' : '';
        $nodeText .= (in_array($tagName, $this->CDATAEncoding)) ? "<{$tagName}{$attrText}><![CDATA[" : "<{$tagName}{$attrText}>";

        if (is_array($tagContent)) {
            foreach ($tagContent as $key => $value) {
                $nodeText .= $this->makeNode($key, $value);
            }
        } else {
            $nodeText .= (in_array($tagName, $this->CDATAEncoding)) ?
                $tagContent : htmlspecialchars($tagContent, defined('ENT_HTML401') ? ENT_COMPAT | ENT_HTML401 : ENT_COMPAT, "UTF-8");
        }

        $nodeText .= (in_array($tagName, $this->CDATAEncoding)) ? "]]></$tagName>" : "</$tagName>";

        return $nodeText . PHP_EOL;
    }

    /**
     * Genarates 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;
    }

    /**
     * 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 $feedItem) {
                if ($feedItem['name'] == 'category') {
                    foreach ($feedItem['content'] as $tag) {
                        echo $this->makeNode($feedItem['name'], $tag, $feedItem['attributes']);
                    }
                } else {
                    echo $this->makeNode($feedItem['name'], $feedItem['content'], $feedItem['attributes']);
                }
            }
            echo $this->endItem();
        }
    }

    /**
     * Make the starting tag of channels
     *
     * @access   private
     * @param    srting  The vale of about tag which is used for only RSS 1.0
     * @return   void
     */
    private function startItem($about = false)
    {
        if ($this->version == RSS2) {
            echo '<item>' . PHP_EOL;
        } elseif ($this->version == RSS1) {
            if ($about) {
                echo "<item rdf:about=\"$about\">" . PHP_EOL;
            } else {
                die('link element is not set .\n It\'s required for RSS 1.0 to be used as about attribute of item');
            }
        } else if ($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;
        }
    }

    /**
     * Closes the open tags at the end of file
     *
     * @access   private
     * @return   void
     */
    private function printTale()
    {
        if ($this->version == RSS2) {
            echo '</channel>' . PHP_EOL . '</rss>';
        } elseif ($this->version == RSS1) {
            echo '</rdf:RDF>';
        } else if ($this->version == ATOM) {
            echo '</feed>';
        }

    }
    // End # public functions ----------------------------------------------

    // Start # private functions ----------------------------------------------

    /**
     * Create a new FeedItem.
     *
     * @return object  instance of FeedItem class
     */
    public function createNewItem()
    {
        $Item = new FeedItem($this->version);
        return $Item;
    }

    /**
     * Add a FeedItem to the main class
     *
     * @param $feedItem object  instance of FeedItem class
     * @return void
     */
    public function addItem($feedItem)
    {
        $this->items[] = $feedItem;
    }

    /**
     * Set the 'title' channel element
     *
     * @param $title string  value of 'title' channel tag
     * @return void
     */
    public function setTitle($title)
    {
        $this->setChannelElement('title', $title);
    }

    /**
     * Set the 'description' channel element
     *
     * @access   public
     * @param    srting  value of 'description' channel tag
     * @return   void
     */
    public function setDescription($desciption)
    {
        $this->setChannelElement('description', $desciption);
    }

    /**
     * Set the 'link' channel element
     *
     * @access   public
     * @param    srting  value of 'link' channel tag
     * @return   void
     */
    public function setLink($link)
    {
        $this->setChannelElement('link', $link);
    }

    /**
     * Set the 'image' channel element
     *
     * @access   public
     * @param    srting  title of image
     * @param    srting  link url of the imahe
     * @param    srting  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    srting  value of 'about' channel tag
     * @return   void
     */
    public function setChannelAbout($url)
    {
        $this->data['ChannelAbout'] = $url;
    }


    // End # private functions ----------------------------------------------

} // end of class FeedWriter


/**
 * FeedItem class - Used as feed element in FeedWriter class
 */
class FeedItem
{
    private $elements = array();    //Collection of feed elements
    private $version;

    /**
     * Constructor
     *
     * @param $version constant    (RSS1/RSS2/ATOM) RSS2 is default.
     */
    function __construct($version = RSS2)
    {
        $this->version = $version;
    }

    /**
     * Set multiple feed elements from an array.
     * Elements which have attributes cannot be added by this method
     *
     * @access   public
     * @param    array   array of elements in 'tagName' => 'tagContent' format.
     * @return   void
     */
    public function addElementArray($elementArray)
    {
        if (!is_array($elementArray)) return;
        foreach ($elementArray as $elementName => $content) {
            $this->addElement($elementName, $content);
        }
    }

    /**
     * Add an element to elements array
     *
     * @param $elementName string  The tag name of an element
     * @param $content string  The content of tag
     * @param $attributes array   Attributes(if any) in 'attrName' => 'attrValue' format
     * @return   void
     */
    public function addElement($elementName, $content, $attributes = null)
    {
        if ($elementName == 'category') {
            if (!array_key_exists('category', $this->elements)) {
                $this->elements[$elementName]['content'] = array($content);
            } else {
                array_push($this->elements[$elementName]['content'], $content);
            }
        } else {
            $this->elements[$elementName]['content'] = $content;
        }
        $this->elements[$elementName]['name'] = $elementName;
        $this->elements[$elementName]['attributes'] = $attributes;
    }

    /**
     * Return the collection of elements in this feed item
     *
     * @access   public
     * @return   array
     */
    public function getElements()
    {
        return $this->elements;
    }

    // Wrapper functions ------------------------------------------------------

    /**
     * Set the 'dscription' element of feed item
     *
     * @access   public
     * @param    string  The content of 'description' element
     * @return   void
     */
    public function setDescription($description)
    {
        $tag = ($this->version == ATOM) ? 'summary' : 'description';
        $this->addElement($tag, $description);
    }

    /**
     * @desc     Set the 'title' element of feed item
     * @access   public
     * @param    string  The content of 'title' element
     * @return   void
     */
    public function setTitle($title)
    {
        $this->addElement('title', $title);
    }

    /**
     * Set the 'date' element of feed item
     *
     * @access   public
     * @param    string  The content of 'date' element
     * @return   void
     */
    public function setDate($date)
    {
        if (!is_numeric($date)) {
            $date = strtotime($date);
        }

        if ($this->version == ATOM) {
            $tag = 'updated';
            $value = date(DATE_ATOM, $date);
        } elseif ($this->version == RSS2) {
            $tag = 'pubDate';
            $value = date(DATE_RSS, $date);
        } else {
            $tag = 'dc:date';
            $value = date("Y-m-d", $date);
        }

        $this->addElement($tag, $value);
    }

    /**
     * Set the 'link' element of feed item
     *
     * @access   public
     * @param    string  The content of 'link' element
     * @return   void
     */
    public function setLink($link)
    {
        if ($this->version == RSS2 || $this->version == RSS1) {
            $this->addElement('link', $link);
        } else {
            $this->addElement('link', '', array('href' => $link));
            $this->addElement('id', FeedWriter::uuid($link, 'urn:uuid:'));
        }

    }

    /**
     * Set the 'encloser' element of feed item
     * For RSS 2.0 only
     *
     * @access   public
     * @param    string  The url attribute of encloser tag
     * @param    string  The length attribute of encloser tag
     * @param    string  The type attribute of encloser tag
     * @return   void
     */
    public function setEncloser($url, $length, $type)
    {
        $attributes = array('url' => $url, 'length' => $length, 'type' => $type);
        $this->addElement('enclosure', '', $attributes);
    }

} // end of class FeedItem