PHP RSS

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。RSS可以是以下三个解释的其中一个： Really Simple Syndication；RDF (Resource Description Framework) Site Summary； Rich Site Summary。但其实这三个解释都是指同一种Syndication的技术。RSS目前广泛用于网上新闻频道，blog和wiki。使用RSS订阅能更快地获取信息，网站提供RSS输出，有利于让用户获取网站内容的最新更新。网络用户可以在客户端借助于支持RSS的聚合工具软件，在不打开网站内容页面的情况下阅读支持RSS输出的网站内容。

下面是一个自动生成RSS的php类

<?php/**** php 动态生成 RSS 类**/define("TIME_ZONE","");define("FEEDCREATOR_VERSION","www.phpernote.com");//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($format)){case "2.0":// fall throughcase "RSS2.0":$this->_feed=new RSSCreator20();break;case "0.91":// fall throughcase "RSS0.91":$this->_feed=new RSSCreator091();break;default:$this->_feed=new RSSCreator091();break;}$vars=get_object_vars($this);foreach ($vars as $key => $value){// prevent overwriting of properties "contentType","encoding"; do not copy "_feed" itselfif(!in_array($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="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($string,0,$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,$length-4)." ...";}function _createGeneratorComment(){return "<!-- generator=\"".FEEDCREATOR_VERSION."\" -->\n";}function _createAdditionalElements($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"],0,-(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],0,1)=='+' OR substr($matches[7],0,1)=='-'){$tzOffset=(substr($matches[7],0,3) * 60 + substr($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 += $tzOffset;return;}if(preg_match("~(\\d{4})-(\\d{2})-(\\d{2})T(\\d{2}):(\\d{2}):(\\d{2})(.*)~",$dateString,$matches)){$this->unix=mktime($matches[4],$matches[5],$matches[6],$matches[2],$matches[3],$matches[1]);if(substr($matches[7],0,1)=='+' OR substr($matches[7],0,1)=='-'){$tzOffset=(substr($matches[7],0,3) * 60 + 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($date,0,22) . ':' . substr($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:RDF\n";$feed.= "    xmlns=\"http://purl.org/rss/1.0/\"\n";$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[$i]->title,"\n\r","  ")))."</title>\n";$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");}}

使用方法

<?phpheader('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='http://www.phpernote.com/';$item->description =$rowbrs['description'];$rss->addItem($item);}mysql_close($db);$rss->saveFeed("RSS2.0","rss.xml");