php生成RSS订阅的方法

<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
<channel>
<title>编程之家</title>
<link>;/link>
<description>编程之家</description>
<item>
<title>RSS Tutorial</title>
<link>网站地址/rss</link>
<description>New RSS tutorial on W3School</description>
</item>
<item>
<title>XML Tutorial</title>
<link>网站地址/xml</link>
<description>New XML tutorial on W3School</description>
</item>
</channel>
</rss>

<?php
/**
** php 动态生成 RSS 类
**/
define("TIME_ZONE","");
define("FEEDCREATOR_VERSION","www.aspzz.cn");//您的网址
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){
??????????? $result="<![CDATA[".$this->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 => $value){
??????????? // prevent overwriting of properties "contentType","encoding"; do not copy "_feed" itself
??????????? if(!in_array($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",$timeout=3600){
??????? $this->_setFormat($format);
??????? $this->_feed->useCached($filename,$timeout);
??? }
}
?
class FeedCreator extends HtmlDescribable{
??? var $title,$link;
??? var $syndicationURL,$language,$copyright,$pubDate,$lastBuildDate,$editor,$editorEmail,$webmaster,$docs,$ttl,$rating,$skipHours,$skipDays;
??? var $xslStyleSheet="";
??? var $items=Array();
??? var $contentType="application/xml";
??? var $encoding="utf-8";
??? 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,$length-4);
??????????? $pos=strrpos($string,".");
??????? }
??????? if($pos>=$length*0.4){
??????????? return substr($string,$pos+1)." ...";
??????? }
?
??????? $pos=strrpos($string," ");
??????? if($pos>=$length-4){
??????????? $string=substr($string," ");
??????? }
??????? if($pos>=$length*0.4){
??????????? return substr($string,$pos)." ...";
??????? }
?
??????? return substr($string,$length-4)." ...";
??? }
?
??? function _createGeneratorComment(){
??????? return "<!-- generator="".FEEDCREATOR_VERSION."" -->n";
??? }
?
??? function _createAdditionalElements($elements,$indentString=""){
??????? $ae="";
??????? if(is_array($elements)){
??????????? foreach($elements AS $key => $value){
??????????????? $ae.= $indentString."<$key>$value</$key>n";
??????????? }
??????? }
??????? return $ae;
??? }
?
??? function _createStylesheetReferences(){
??????? $xml="";
??????? if($this->cssStyleSheet) $xml .= "<?xml-stylesheet href="".$this->cssStyleSheet."" type="text/css"?>n";
??????? if($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($fileInfo["basename"],-(strlen($fileInfo["extension"])+1)).".xml";
??? }
?
??? function _redirect($filename){
??????? Header("Content-Type: ".$this->contentType."; charset=".$this->encoding."; filename=".basename($filename));
??????? Header("Content-Disposition: inline; filename=".basename($filename));
??????? readfile($filename,"r");
??????? die();
??? }
?
??? function useCached($filename="",$timeout=3600){
??????? $this->_timeout=$timeout;
??????? if($filename==""){
??????????? $filename=$this->_generateFilename();
??????? }
??????? if(file_exists($filename) && (time()-filemtime($filename) < $timeout)){
??????????? $this->_redirect($filename);
??????? }
??? }
?
??? function saveFeed($filename="",$displayContents=true){
??????? if($filename==""){
??????????? $filename=$this->_generateFilename();
??????? }
??????? $feedFile=fopen($filename,"w+");
??????? if($feedFile){
??????????? fputs($feedFile,$this->createFeed());
??????????? fclose($feedFile);
??????????? if($displayContents){
??????????????? $this->_redirect($filename);
??????????? }
??????? }else{
??????????? echo "<br /><b>Error creating feed file,please check write permissions.</b><br />";
??????? }
??? }
}
?
class FeedDate{
??? var $unix;
??? function FeedDate($dateString=""){
??????? if($dateString=="") $dateString=date("r");
??????? if(is_integer($dateString)){
??????????? $this->unix=$dateString;
??????????? return;
??????? }
??????? if(preg_match("~(?:(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun),s+)?(d{1,2})s+([a-zA-Z]{3})s+(d{4})s+(d{2}):(d{2}):(d{2})s+(.*)~",$dateString,$matches)){
??????????? $months=Array("Jan"=>1,"Feb"=>2,"Mar"=>3,"Apr"=>4,"May"=>5,"Jun"=>6,"Jul"=>7,"Aug"=>8,"Sep"=>9,"Oct"=>10,"Nov"=>11,"Dec"=>12);
??????????? $this->unix=mktime($matches[4],$matches[5],$matches[6],$months[$matches[2]],$matches[1],$matches[3]);
??????????? if(substr($matches[7],1)=='+' OR substr($matches[7],1)=='-'){
??????????????? $tzOffset=(substr($matches[7],3) * 60 + substr($matches[7],-2)) * 60;
??????????? }else{
??????????????? if(strlen($matches[7])==1){
??????????????????? $oneHour=3600;
??????????????????? $ord=ord($matches[7]);
??????????????????? if($ord < ord("M")){
??????????????????????? $tzOffset=(ord("A") - $ord - 1) * $oneHour;
??????????????????? } elseif($ord >= ord("M") && $matches[7]!="Z"){
??????????????????????? $tzOffset=($ord - ord("M")) * $oneHour;
??????????????????? } elseif($matches[7]=="Z"){
??????????????????????? $tzOffset=0;
??????????????????? }
??????????????? }
??????????????? switch ($matches[7]){
??????????????????? case "UT":
??????????????????? case "GMT":??? $tzOffset=0;
??????????????? }
??????????? }
??????????? $this->unix += $tzOffset;
??????????? return;
??????? }
??????? if(preg_match("~(d{4})-(d{2})-(d{2})T(d{2}):(d{2}):(d{2})(.*)~",$matches)){
??????????? $this->unix=mktime($matches[4],$matches[2],$matches[3],$matches[1]);
??????????? if(substr($matches[7],-2)) * 60;
??????????? }else{
??????????????? if($matches[7]=="Z"){
??????????????????? $tzOffset=0;
??????????????? }
??????????? }
??????????? $this->unix += $tzOffset;
??????????? return;
??????? }
??????? $this->unix=0;
??? }
?
??? function rfc822(){
??????? $date=gmdate("Y-m-d H:i:s",$this->unix);
??????? if(TIME_ZONE!="") $date .= " ".str_replace(":","",TIME_ZONE);
??????? return $date;
??? }
?
??? function iso8601(){
??????? $date=gmdate("Y-m-d H:i:s",$this->unix);
??????? $date=substr($date,22) . ':' . substr($date,-2);
??????? if(TIME_ZONE!="") $date=str_replace("+00:00",TIME_ZONE,$date);
??????? return $date;
??? }
?
??? function unix(){
??????? return $this->unix;
??? }
}
?
class RSSCreator10 extends FeedCreator{
??? function createFeed(){
??????? $feed="<?xml version="1.0" encoding="".$this->encoding.""?>n";
??????? $feed.= $this->_createGeneratorComment();
??????? if($this->cssStyleSheet==""){
??????????? $cssStyleSheet="http://www.w3.org/2000/08/w3c-synd/style.css";
??????? }
??????? $feed.= $this->_createStylesheetReferences();
??????? $feed.= "<rdf:RDFn";
??????? $feed.= "??? xmlns="http://purl.org/rss/1.0/"n";
??????? $feed.= "??? xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"n";
??????? $feed.= "??? xmlns:slash="http://purl.org/rss/1.0/modules/slash/"n";
??????? $feed.= "??? xmlns:dc="http://purl.org/dc/elements/1.1/">n";
??????? $feed.= "??? <channel rdf:about="".$this->syndicationURL."">n";
??????? $feed.= "??????? <title>".htmlspecialchars($this->title)."</title>n";
??????? $feed.= "??????? <description>".htmlspecialchars($this->description)."</description>n";
??????? $feed.= "??????? <link>".$this->link."</link>n";
??????? if($this->image!=null){
??????????? $feed.= "??????? <image rdf:resource="".$this->image->url."" />n";
??????? }
??????? $now=new FeedDate();
??????? $feed.= "?????? <dc:date>".htmlspecialchars($now->iso8601())."</dc:date>n";
??????? $feed.= "??????? <items>n";
??????? $feed.= "??????????? <rdf:Seq>n";
??????? for ($i=0;$i<count($this->items);$i++){
??????????? $feed.= "??????????????? <rdf:li rdf:resource="".htmlspecialchars($this->items[$i]->link).""/>n";
??????? }
??????? $feed.= "??????????? </rdf:Seq>n";
??????? $feed.= "??????? </items>n";
??????? $feed.= "??? </channel>n";
??????? if($this->image!=null){
??????????? $feed.= "??? <image rdf:about="".$this->image->url."">n";
??????????? $feed.= "??????? <title>".$this->image->title."</title>n";
??????????? $feed.= "??????? <link>".$this->image->link."</link>n";
??????????? $feed.= "??????? <url>".$this->image->url."</url>n";
??????????? $feed.= "??? </image>n";
??????? }
??????? $feed.= $this->_createAdditionalElements($this->additionalElements,"??? ");
?
??????? for ($i=0;$i<count($this->items);$i++){
??????????? $feed.= "??? <item rdf:about="".htmlspecialchars($this->items[$i]->link)."">n";
??????????? //$feed.= "??????? <dc:type>Posting</dc:type>n";
??????????? $feed.= "??????? <dc:format>text/html</dc:format>n";
??????????? if($this->items[$i]->date!=null){
??????????????? $itemDate=new FeedDate($this->items[$i]->date);
??????????????? $feed.= "??????? <dc:date>".htmlspecialchars($itemDate->iso8601())."</dc:date>n";
??????????? }
??????????? if($this->items[$i]->source!=""){
??????????????? $feed.= "??????? <dc:source>".htmlspecialchars($this->items[$i]->source)."</dc:source>n";
??????????? }
??????????? if($this->items[$i]->author!=""){
??????????????? $feed.= "??????? <dc:creator>".htmlspecialchars($this->items[$i]->author)."</dc:creator>n";
??????????? }
??????????? $feed.= "??????? <title>".htmlspecialchars(strip_tags(strtr($this->items[$i]->title,"nr","? ")))."</title>n";
??????????? $feed.= "??????? <link>".htmlspecialchars($this->items[$i]->link)."</link>n";
??????????? $feed.= "??????? <description>".htmlspecialchars($this->items[$i]->description)."</description>n";
??????????? $feed.= $this->_createAdditionalElements($this->items[$i]->additionalElements,"??????? ");
??????????? $feed.= "??? </item>n";
??????? }
??????? $feed.= "</rdf:RDF>n";
??????? return $feed;
??? }
}
?
class RSSCreator091 extends FeedCreator{
??? var $RSSVersion;
?
??? function RSSCreator091(){
??????? $this->_setRSSVersion("0.91");
??????? $this->contentType="application/rss+xml";
??? }
?
??? function _setRSSVersion($version){
??????? $this->RSSVersion=$version;
??? }
?
??? function createFeed(){
??????? $feed="<?xml version="1.0" encoding="".$this->encoding.""?>n";
??????? $feed.= $this->_createGeneratorComment();
??????? $feed.= $this->_createStylesheetReferences();
??????? $feed.= "<rss version="".$this->RSSVersion."">n";
??????? $feed.= "??? <channel>n";
??????? $feed.= "??????? <title>".FeedCreator::iTrunc(htmlspecialchars($this->title),100)."</title>n";
??????? $this->descriptionTruncSize=500;
??????? $feed.= "??????? <description>".$this->getDescription()."</description>n";
??????? $feed.= "??????? <link>".$this->link."</link>n";
??????? $now=new FeedDate();
??????? $feed.= "??????? <lastBuildDate>".htmlspecialchars($now->rfc822())."</lastBuildDate>n";
??????? $feed.= "??????? <generator>".FEEDCREATOR_VERSION."</generator>n";
?
??????? if($this->image!=null){
??????????? $feed.= "??????? <image>n";
??????????? $feed.= "??????????? <url>".$this->image->url."</url>n";
??????????? $feed.= "??????????? <title>".FeedCreator::iTrunc(htmlspecialchars($this->image->title),100)."</title>n";
??????????? $feed.= "??????????? <link>".$this->image->link."</link>n";
??????????? if($this->image->width!=""){
??????????????? $feed.= "??????????? <width>".$this->image->width."</width>n";
??????????? }
??????????? if($this->image->height!=""){
??????????????? $feed.= "??????????? <height>".$this->image->height."</height>n";
??????????? }
??????????? if($this->image->description!=""){
??????????????? $feed.= "??????????? <description>".$this->image->getDescription()."</description>n";
??????????? }
??????????? $feed.= "??????? </image>n";
??????? }
??????? if($this->language!=""){
??????????? $feed.= "??????? <language>".$this->language."</language>n";
??????? }
??????? if($this->copyright!=""){
??????????? $feed.= "??????? <copyright>".FeedCreator::iTrunc(htmlspecialchars($this->copyright),100)."</copyright>n";
??????? }
??????? if($this->editor!=""){
??????????? $feed.= "??????? <managingEditor>".FeedCreator::iTrunc(htmlspecialchars($this->editor),100)."</managingEditor>n";
??????? }
??????? if($this->webmaster!=""){
??????????? $feed.= "??????? <webMaster>".FeedCreator::iTrunc(htmlspecialchars($this->webmaster),100)."</webMaster>n";
??????? }
??????? if($this->pubDate!=""){
??????????? $pubDate=new FeedDate($this->pubDate);
??????????? $feed.= "??????? <pubDate>".htmlspecialchars($pubDate->rfc822())."</pubDate>n";
??????? }
??????? if($this->category!=""){
??????????? $feed.= "??????? <category>".htmlspecialchars($this->category)."</category>n";
??????? }
??????? if($this->docs!=""){
??????????? $feed.= "??????? <docs>".FeedCreator::iTrunc(htmlspecialchars($this->docs),500)."</docs>n";
??????? }
??????? if($this->ttl!=""){
??????????? $feed.= "??????? <ttl>".htmlspecialchars($this->ttl)."</ttl>n";
??????? }
??????? if($this->rating!=""){
??????????? $feed.= "??????? <rating>".FeedCreator::iTrunc(htmlspecialchars($this->rating),500)."</rating>n";
??????? }
??????? if($this->skipHours!=""){
??????????? $feed.= "??????? <skipHours>".htmlspecialchars($this->skipHours)."</skipHours>n";
??????? }
??????? if($this->skipDays!=""){
??????????? $feed.= "??????? <skipDays>".htmlspecialchars($this->skipDays)."</skipDays>n";
??????? }
??????? $feed.= $this->_createAdditionalElements($this->additionalElements,"??? ");
?
??????? for ($i=0;$i<count($this->items);$i++){
??????????? $feed.= "??????? <item>n";
??????????? $feed.= "??????????? <title>".FeedCreator::iTrunc(htmlspecialchars(strip_tags($this->items[$i]->title)),100)."</title>n";
??????????? $feed.= "??????????? <link>".htmlspecialchars($this->items[$i]->link)."</link>n";
??????????? $feed.= "??????????? <description>".$this->items[$i]->getDescription()."</description>n";
?
??????????? if($this->items[$i]->author!=""){
??????????????? $feed.= "??????????? <author>".htmlspecialchars($this->items[$i]->author)."</author>n";
??????????? }
??????????? /*
???????????? // on hold
???????????? if($this->items[$i]->source!=""){
???????????? $feed.= "??????????? <source>".htmlspecialchars($this->items[$i]->source)."</source>n";
???????????? }
???????????? */
??????????? if($this->items[$i]->category!=""){
??????????????? $feed.= "??????????? <category>".htmlspecialchars($this->items[$i]->category)."</category>n";
??????????? }
??????????? if($this->items[$i]->comments!=""){
??????????????? $feed.= "??????????? <comments>".htmlspecialchars($this->items[$i]->comments)."</comments>n";
??????????? }
??????????? if($this->items[$i]->date!=""){
??????????????? $itemDate=new FeedDate($this->items[$i]->date);
??????????????? $feed.= "??????????? <pubDate>".htmlspecialchars($itemDate->rfc822())."</pubDate>n";
??????????? }
??????????? if($this->items[$i]->guid!=""){
??????????????? $feed.= "??????????? <guid>".htmlspecialchars($this->items[$i]->guid)."</guid>n";
??????????? }
??????????? $feed.= $this->_createAdditionalElements($this->items[$i]->additionalElements,"??????? ");
??????????? $feed.= "??????? </item>n";
??????? }
??????? $feed.= "??? </channel>n";
??????? $feed.= "</rss>n";
??????? return $feed;
??? }
}
?
class RSSCreator20 extends RSSCreator091{
?
??? function RSSCreator20(){
??????? parent::_setRSSVersion("2.0");
??? }
}

<?php
header('Content-Type:text/html; charset=utf-8');
$db=mysql_connect('127.0.0.1','root','123456');
mysql_query("set names utf8");
mysql_select_db('dbname',$db);
$brs=mysql_query('select * from article order by add_time desc limit 0,10',$db);
$rss=new UniversalFeedCreator();
$rss->title="页面标题";
$rss->link="网址http://";
$rss->description="rss标题";
while($rowbrs=mysql_fetch_array($brs)){
??? $item=new FeedItem();
??? $item->title =$rowbrs['subject'];
??? $item->link='/';
??? $item->description =$rowbrs['description'];
??? $rss->addItem($item);
}
mysql_close($db);
$rss->saveFeed("RSS2.0","rss.xml");