php中RSS订阅类的使用方法-tutorial php-php.cn

这篇文章主要介绍了php生成RSS订阅的方法,较为详细的分析了一个RSS订阅类及其具体使用技巧,非常具有实用价值,需要的朋友可以参考下

本文实例讲述了php生成RSS订阅的方法。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：

代码如下:

   PHP中文网 //m.sbmmt.com/ PHP中文网  RSS Tutorial 网站地址/rss New RSS tutorial on W3School   XML Tutorial 网站地址/xml New XML tutorial on W3School

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下面分享一段使用 php 动态生成 RSS 的代码示例：

代码如下:

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 => $value){ // prevent overwriting of properties "contentType","encoding"; do not copy "_feed" itself if(!in_array($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",$filename="",$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 "\n"; } function _createAdditionalElements($elements,$indentString=""){ $ae=""; if(is_array($elements)){ foreach($elements AS $key => $value){ $ae.= $indentString."<$key>$value\n"; } } return $ae; } function _createStylesheetReferences(){ $xml=""; if($this->cssStyleSheet) $xml .= "cssStyleSheet."\" type=\"text/css\"?>\n"; if($this->xslStyleSheet) $xml .= "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 "
Error creating feed file, please check write permissions.
"; } } } 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.= "\n"; $feed.= " syndicationURL."\">\n"; $feed.= " ".htmlspecialchars($this->title)."\n"; $feed.= " ".htmlspecialchars($this->description)."\n"; $feed.= " ".$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"; $feed.= " ".$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"; $feed.= " ".htmlspecialchars($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"; $feed.= " ".$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"; $feed.= " ".$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"; $feed.= " ".htmlspecialchars($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"); } }

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使用示例：

代码如下:

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='//www.jb51.net/'; $item->description =$rowbrs['description']; $rss->addItem($item); } mysql_close($db); $rss->saveFeed("RSS2.0","rss.xml");

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总结：以上就是本篇文的全部内容，希望能对大家的学习有所帮助。