RSS(简易信息聚合，也叫聚合内容)是一种描述和同步网站内容的格式。使用RSS订阅能让用户更快地获取网站最新内容，也有利与网站内容更广泛的传播。目前RSS使用最广泛的是XML文件格式。

创建RSS源(服务端)：

1、主文件rss.php：

require("rss_class.php");

$host = 'localhost'; //数据库地址

$user = 'root'; //帐号

$pass = '123456; //密码

$db = 'data'; //数据库名

$con = mysql_connect($host,$user,$pass);

if (!$con) die('Could not connect:'.mysql_error());

mysql_select_db($db,$con);

mysql_query('SET NAMES gb2312'); //编码

$result = mysql_query("select * from news",$con);

$rss = new UniversalFeedCreator();

$rss->title = "title"; //rss标题

$rss->link = "http://www.zhixing123.cn/"; //rss源地址

$rss->description = "description"; //rss描述

while($rs=mysql_fetch_array($result)){

$item = new FeedItem();

$item->title =$rs['title']; //标题字段$item->link = 'http://www.zhixing123.cn/post'.$rs['id']; //id标识字段

$item->description =$rs['description']; //描述字段

$rss->addItem($item);

}

$rss->saveFeed("RSS2.0", "rss.xml"); //输出xml

?>

2、类文件rss_class.php：

define("TIME_ZONE","");

define("FEEDCREATOR_VERSION", //generator

class FeedItem extends HtmlDescribable {

var $title, $description, $link;

var $author, $authorEmail, $image, $category, $comments, $guid, $source, $creator;

var $date;

var $additionalElements = Array();

}

class FeedImage extends HtmlDescribable {

var $title, $url, $link;

var $width, $height, $description;

}

class HtmlDescribable {

var $descriptionHtmlSyndicated;

var $descriptionTruncSize;

function getDescription() {

$descriptionField = new FeedHtmlField($this->description);

$descriptionField->syndicateHtml = $this->descriptionHtmlSyndicated;

$descriptionField->truncSize = $this->descriptionTruncSize;

return $descriptionField->output();

}

}

class FeedHtmlField {

var $rawFieldContent;

var $truncSize, $syndicateHtml;

function FeedHtmlField($parFieldContent) {

if ($parFieldContent) {

$this->rawFieldContent = $parFieldContent;

}

}

function output() {

if (!$this->rawFieldContent) {

$result = "";

} elseif ($this->syndicateHtml) {

$result = "rawFieldContent."]]>";

} else {

if ($this->truncSize and is_int($this->truncSize)) {

$result = FeedCreator::iTrunc(htmlspecialchars($this->rawFieldContent),$this->truncSize);

} else {

$result = htmlspecialchars($this->rawFieldContent);

}

}

return $result;

}

}

class UniversalFeedCreator extends FeedCreator {

var $_feed;

function _setFormat($format) {

switch (strtoupper($format)) {

case "2.0":

// fall through

case "RSS2.0":

$this->_feed = new RSSCreator20();

break;

case "0.91":

// fall through

case "RSS0.91":

$this->_feed = new RSSCreator091();

break;

default:

$this->_feed = new RSSCreator091();

break;

}

$vars = get_object_vars($this);

foreach ($vars as $key => $value) {

if (!in_array($key, array("_feed", "contentType", "encoding"))) {

$this->_feed->{$key} = $this->{$key};

}

}

}

function createFeed($format = "RSS0.91") {

$this->_setFormat($format);

return $this->_feed->createFeed();

}

function saveFeed($format="RSS0.91", $filename="", $displayContents=true) {

$this->_setFormat($format);

$this->_feed->saveFeed($filename, $displayContents);

}

function useCached($format="RSS0.91", $filename="", $timeout=3600) {

$this->_setFormat($format);

$this->_feed->useCached($filename, $timeout);

}

}

class FeedCreator extends HtmlDescribable {

var $title, $description, $link;

var $syndicationURL, $image, $language, $copyright, $pubDate, $lastBuildDate, $editor, $editorEmail, $webmaster, $category, $docs, $ttl, $rating, $skipHours, $skipDays;

var $xslStyleSheet = "";

var $items = Array();

var $contentType = "application/xml";

var $encoding = "gb2312"; //编码

var $additionalElements = Array();

function addItem($item) {

$this->items[] = $item;

}

function clearItem2Null() {

$this->items = array();

}

function iTrunc($string, $length) {

if (strlen($string)<=$length) {

return $string;

}

$pos = strrpos($string,".");

if ($pos>=$length-4) {

$string = substr($string,0,$length-4);

$pos = strrpos($string,".");

}

if ($pos>=$length*0.4) {

return substr($string,0,$pos+1)." ...";

}

$pos = strrpos($string," ");

if ($pos>=$length-4) {

$string = substr($string,0,$length-4);

$pos = strrpos($string," ");

}

if ($pos>=$length*0.4) {

return substr($string,0,$pos)." ...";

}

return substr($string,0,$length-4)." ...";

}

function _createGeneratorComment() {

return "\n";

}

function _createAdditionalElements($elements, $indentString="") {

$ae = "";

if (is_array($elements)) {

foreach($elements AS $key => $value) {

$ae.= $indentString."$value$key>\n";

}

}

return $ae;

}

function _createStylesheetReferences() {

$xml = "";

if (isset($this->cssStyleSheet)) $xml .= "<?xml-stylesheet href=\"".$this->cssStyleSheet."\" type=\"text/css\"?>\n";

if (isset($this->xslStyleSheet)) $xml .= "<?xml-stylesheet href=\"".$this->xslStyleSheet."\" type=\"text/xsl\"?>\n";

return $xml;

}

function createFeed() {

}

function _generateFilename() {

$fileInfo = pathinfo($_SERVER["PHP_SELF"]);

return substr($fileInfo["basename"],0,-(strlen($fileInfo["extension"])+1)).".xml";