php生成RSS订阅的方法_PHP

本文实例讲述了php生成RSS订阅的方法。分享给大家供大家参考。具体分析如下：

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。
从技术上来说一个RSS文件就是一段规范的XML数据，该文件一般以rss，xml或者rdf作为后缀，下面是一段 rss 文件的内容示例：

 <br /> <br /> <br /><title></title> <br /><link>http://www.bitsCN.com/ <br /> <br /> <br /><title>RSS Tutorial</title> <br /><link>网站地址/rss <br />New RSS tutorial on W3School <br /> <br /> <br /><title>XML Tutorial</title> <br /><link>网站地址/xml <br />New XML tutorial on W3School <br /> <br /> <br />

下面分享一段使用 php 动态生成 RSS 的代码示例：

<?php <br />/** <br />** php 动态生成 RSS 类 <br />**/ <br />define("TIME_ZONE",""); <br />define("FEEDCREATOR_VERSION","www.bitsCN.com");//您的网址 <br />class FeedItem extends HtmlDescribable{ <br />    var $title,$description,$link; <br />    var $author,$authorEmail,$image,$category,$comments,$guid,$source,$creator;<br />    var $date;<br />    var $additionalElements=Array(); <br />} <br /> <br />class FeedImage extends HtmlDescribable{ <br />    var $title,$url,$link; <br />    var $width,$height,$description; <br />} <br /> <br />class HtmlDescribable{ <br />    var $descriptionHtmlSyndicated; <br />    var $descriptionTruncSize; <br /> <br />    function getDescription(){ <br />        $descriptionField=new FeedHtmlField($this->description); <br />        $descriptionField->syndicateHtml=$this->descriptionHtmlSyndicated;<br />        $descriptionField->truncSize=$this->descriptionTruncSize;<br />        return $descriptionField->output(); <br />    } <br />} <br /> <br />class FeedHtmlField{ <br />    var $rawFieldContent; <br />    var $truncSize,$syndicateHtml; <br />    function FeedHtmlField($parFieldContent){ <br />        if($parFieldContent){ <br />            $this->rawFieldContent=$parFieldContent; <br />        } <br />    } <br />    function output(){ <br />        if(!$this->rawFieldContent){ <br />            $result=""; <br />        }    elseif($this->syndicateHtml){ <br />            $result="rawFieldContent."]]>"; <br />        }else{ <br />            if($this->truncSize and is_int($this->truncSize)){ <br />                $result=FeedCreator::iTrunc(htmlspecialchars($this->rawFieldContent),$this->truncSize);<br />            }else{ <br />                $result=htmlspecialchars($this->rawFieldContent); <br />            } <br />        } <br />        return $result; <br />    } <br />} <br /> <br />class UniversalFeedCreator extends FeedCreator{ <br />    var $_feed; <br />    function _setFormat($format){ <br />        switch (strtoupper($format)){ <br />            case "2.0": <br />                // fall through <br />            case "RSS2.0": <br />                $this->_feed=new RSSCreator20(); <br />                break; <br />            case "0.91": <br />                // fall through <br />            case "RSS0.91": <br />                $this->_feed=new RSSCreator091(); <br />                break; <br />            default: <br />                $this->_feed=new RSSCreator091(); <br />                break; <br />        } <br />        $vars=get_object_vars($this); <br />        foreach ($vars as $key => $value){ <br />            // prevent overwriting of properties "contentType","encoding"; do not copy "_feed" itself <br />            if(!in_array($key, array("_feed","contentType","encoding"))){ <br />                $this->_feed->{$key}=$this->{$key}; <br />            } <br />        } <br />    } <br /> <br />    function createFeed($format="RSS0.91"){ <br />        $this->_setFormat($format); <br />        return $this->_feed->createFeed(); <br />    } <br /> <br />    function saveFeed($format="RSS0.91",$filename="",$displayContents=true){ <br />        $this->_setFormat($format); <br />        $this->_feed->saveFeed($filename,$displayContents); <br />    } <br /> <br />    function useCached($format="RSS0.91",$filename="",$timeout=3600){ <br />        $this->_setFormat($format); <br />        $this->_feed->useCached($filename,$timeout); <br />    } <br />} <br /> <br />class FeedCreator extends HtmlDescribable{ <br />    var $title,$description,$link; <br />    var $syndicationURL,$image,$language,$copyright,$pubDate,$lastBuildDate,$editor,$editorEmail,$webmaster,$category,$docs,$ttl,$rating,$skipHours,$skipDays;<br />    var $xslStyleSheet=""; <br />    var $items=Array(); <br />    var $contentType="application/xml"; <br />    var $encoding="utf-8"; <br />    var $additionalElements=Array(); <br /> <br />    function addItem($item){ <br />        $this->items[]=$item; <br />    } <br /> <br />    function clearItem2Null(){ <br />        $this->items=array(); <br />    } <br /> <br />    function iTrunc($string,$length){ <br />        if(strlen($string)<=$length){ <br />            return $string; <br />        } <br /> <br />        $pos=strrpos($string,"."); <br />        if($pos>=$length-4){ <br />            $string=substr($string,0,$length-4); <br />            $pos=strrpos($string,"."); <br />        } <br />        if($pos>=$length*0.4){ <br />            return substr($string,0,$pos+1)." ..."; <br />        } <br /> <br />        $pos=strrpos($string," "); <br />        if($pos>=$length-4){ <br />            $string=substr($string,0,$length-4); <br />            $pos=strrpos($string," "); <br />        } <br />        if($pos>=$length*0.4){ <br />            return substr($string,0,$pos)." ..."; <br />        } <br /> <br />        return substr($string,0,$length-4)." ..."; <br />    } <br /> <br />    function _createGeneratorComment(){ <br />        return "<!---ecms -ecms -ecms  generator="".FEEDCREATOR_VERSION."" -->\n"; <br />    } <br /> <br />    function _createAdditionalElements($elements,$indentString=""){ <br />        $ae=""; <br />        if(is_array($elements)){ <br />            foreach($elements AS $key => $value){ <br />                $ae.= $indentString."$value\n"; <br />            } <br />        } <br />        return $ae; <br />    } <br /> <br />    function _createStylesheetReferences(){ <br />        $xml=""; <br />        if($this->cssStyleSheet) $xml .= "cssStyleSheet."\" type=\"text/css\"?>\n"; <br />        if($this->xslStyleSheet) $xml .= "xslStyleSheet."\" type=\"text/xsl\"?>\n"; <br />        return $xml; <br />    } <br /> <br />    function createFeed(){} <br /> <br />    function _generateFilename(){ <br />        $fileInfo=pathinfo($_SERVER["PHP_SELF"]); <br />        return substr($fileInfo["basename"],0,-(strlen($fileInfo["extension"])+1)).".xml"; <br />    } <br /> <br />    function _redirect($filename){ <br />        Header("Content-Type: ".$this->contentType."; charset=".$this->encoding."; filename=".basename($filename)); <br />        Header("Content-Disposition: inline; filename=".basename($filename)); <br />        readfile($filename,"r"); <br />        die(); <br />    } <br /> <br />    function useCached($filename="",$timeout=3600){ <br />        $this->_timeout=$timeout; <br />        if($filename==""){ <br />            $filename=$this->_generateFilename<strong>（本文来源gaodai#ma#com搞@@代~&码网</strong><pre>搞代gaodaima码

();
}
if(file_exists($filename) && (time()-filemtime($filename) < $timeout)){
$this->_redirect($filename);
}
}

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=”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.= ” syndicationURL.”\”>\n”;
$feed.= ” “.htmlspecialchars($this->title).”\n”;
$feed.= ” “.htmlspecialchars($this->description).”\n”;
$feed.= ” <link>”.$this->link.”\n”;
if($this->image!=null){
$feed.= ” image->url.”\” />\n”;
}
$now=new FeedDate();
$feed.= ” “.htmlspecialchars($now->iso8601()).”\n”;
$feed.= ” \n”;
$feed.= ” \n”;
for ($i=0;$iitems);$i++){
$feed.= ” items[$i]->link).”\”/>\n”;
}
$feed.= ” \n”;
$feed.= ” \n”;
$feed.= ” \n”;
if($this->image!=null){
$feed.= ” image->url.”\”>\n”;
$feed.= ” “.$this->image->title.”\n”;
$feed.= ” <link>”.$this->image->link.”\n”;
$feed.= ” “.$this->image->url.”\n”;
$feed.= ” \n”;
}
$feed.= $this->_createAdditionalElements($this->additionalElements,” “);

for ($i=0;$iitems);$i++){
$feed.= ” items[$i]->link).”\”>\n”;
//$feed.= ” Posting\n”;
$feed.= ” text/html\n”;
if($this->items[$i]->date!=null){
$itemDate=new FeedDate($this->items[$i]->date);
$feed.= ” “.htmlspecialchars($itemDate->iso8601()).”\n”;
}
if($this->items[$i]->source!=””){
$feed.= ” “.htmlspecialchars($this->items[$i]->source).”\n”;
}
if($this->items[$i]->author!=””){
$feed.= ” “.htmlspecialchars($this->items[$i]->author).”\n”;
}
$feed.= ” “.htmlspecialchars(strip_tags(strtr($this->items[$i]->title,”\n\r”,” “))).”\n”;
$feed.= ” <link>”.htmlspecialchars($this->items[$i]->link).”\n”;
$feed.= ” “.htmlspecialchars($this->items[$i]->description).”\n”;
$feed.= $this->_createAdditionalElements($this->items[$i]->additionalElements,” “);
$feed.= ” \n”;
}
$feed.= “\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=”encoding.”\”?>\n”;
$feed.= $this->_createGeneratorComment();
$feed.= $this->_createStylesheetReferences();
$feed.= “RSSVersion.”\”>\n”;
$feed.= ” \n”;
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars($this->title),100).”\n”;
$this->descriptionTruncSize=500;
$feed.= ” “.$this->getDescription().”\n”;
$feed.= ” <link>”.$this->link.”\n”;
$now=new FeedDate();
$feed.= ” “.htmlspecialchars($now->rfc822()).”\n”;
$feed.= ” “.FEEDCREATOR_VERSION.”\n”;

if($this->image!=null){
$feed.= ” \n”;
$feed.= ” “.$this->image->url.”\n”;
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars($this->image->title),100).”\n”;
$feed.= ” <link>”.$this->image->link.”\n”;
if($this->image->width!=””){
$feed.= ” “.$this->image->width.”\n”;
}
if($this->image->height!=””){
$feed.= ” “.$this->image->height.”\n”;
}
if($this->image->description!=””){
$feed.= ” “.$this->image->getDescription().”\n”;
}
$feed.= ” \n”;
}
if($this->language!=””){
$feed.= ” “.$this->language.”\n”;
}
if($this->copyright!=””){
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars($this->copyright),100).”\n”;
}
if($this->editor!=””){
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars($this->editor),100).”\n”;
}
if($this->webmaster!=””){
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars($this->webmaster),100).”\n”;
}
if($this->pubDate!=””){
$pubDate=new FeedDate($this->pubDate);
$feed.= ” “.htmlspecialchars($pubDate->rfc822()).”\n”;
}
if($this->category!=””){
$feed.= ” “.htmlspecialchars($this->category).”\n”;
}
if($this->docs!=””){
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars($this->docs),500).”\n”;
}
if($this->ttl!=””){
$feed.= ” “.htmlspecialchars($this->ttl).”\n”;
}
if($this->rating!=””){
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars($this->rating),500).”\n”;
}
if($this->skipHours!=””){
$feed.= ” “.htmlspecialchars($this->skipHours).”\n”;
}
if($this->skipDays!=””){
$feed.= ” “.htmlspecialchars($this->skipDays).”\n”;
}
$feed.= $this->_createAdditionalElements($this->additionalElements,” “);

for ($i=0;$iitems);$i++){
$feed.= ” \n”;
$feed.= ” “.FeedCreator::iTrunc(htmlspecialchars(strip_tags($this->items[$i]->title)),100).”\n”;
$feed.= ” <link>”.htmlspecialchars($this->items[$i]->link).”\n”;
$feed.= ” “.$this->items[$i]->getDescription().”\n”;

if($this->items[$i]->author!=””){
$feed.= ” “.htmlspecialchars($this->items[$i]->author).”\n”;
}
/*
// on hold
if($this->items[$i]->source!=””){
$feed.= ” “.htmlspecialchars($this->items[$i]->source).”\n”;
}
*/
if($this->items[$i]->category!=””){
$feed.= ” “.htmlspecialchars($this->items[$i]->category).”\n”;
}
if($this->items[$i]->comments!=””){
$feed.= ” “.htmlspecialchars($this->items[$i]->comments).”\n”;
}
if($this->items[$i]->date!=””){
$itemDate=new FeedDate($this->items[$i]->date);
$feed.= ” “.htmlspecialchars($itemDate->rfc822()).”\n”;
}
if($this->items[$i]->guid!=””){
$feed.= ” “.htmlspecialchars($this->items[$i]->guid).”\n”;
}
$feed.= $this->_createAdditionalElements($this->items[$i]->additionalElements,” “);
$feed.= ” \n”;
}
$feed.= ” \n”;
$feed.= “\n”;
return $feed;
}
}

class RSSCreator20 extends RSSCreator091{

function RSSCreator20(){
parent::_setRSSVersion(“2.0”);
}
}
使用示例：

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

希望本文所述对大家的php程序设计有所帮助。

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