php生成RSS订阅的方法
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：ReallySimpleSyndication；RDF(ResourceDescriptionFramework)SiteSummary；RichSiteSummary。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：
<?xmlversion="1.0"encoding="utf-8"?> <rssversion="2.0"> <channel> <title>毛票票</title> <link>https://www.nhooo.com/</link> <description>毛票票</description> <item> <title>RSSTutorial</title> <link>网站地址/rss</link> <description>NewRSStutorialonW3School</description> </item> <item> <title>XMLTutorial</title> <link>网站地址/xml</link> <description>NewXMLtutorialonW3School</description> </item> </channel> </rss>
下面分享一段使用php动态生成RSS的代码示例：
<?php
/**
**php动态生成RSS类
**/
define("TIME_ZONE","");
define("FEEDCREATOR_VERSION","www.nhooo.com");//您的网址
classFeedItemextendsHtmlDescribable{
var$title,$description,$link;
var$author,$authorEmail,$image,$category,$comments,$guid,$source,$creator;
var$date;
var$additionalElements=Array();
}
classFeedImageextendsHtmlDescribable{
var$title,$url,$link;
var$width,$height,$description;
}
classHtmlDescribable{
var$descriptionHtmlSyndicated;
var$descriptionTruncSize;
functiongetDescription(){
$descriptionField=newFeedHtmlField($this->description);
$descriptionField->syndicateHtml=$this->descriptionHtmlSyndicated;
$descriptionField->truncSize=$this->descriptionTruncSize;
return$descriptionField->output();
}
}
classFeedHtmlField{
var$rawFieldContent;
var$truncSize,$syndicateHtml;
functionFeedHtmlField($parFieldContent){
if($parFieldContent){
$this->rawFieldContent=$parFieldContent;
}
}
functionoutput(){
if(!$this->rawFieldContent){
$result="";
} elseif($this->syndicateHtml){
$result="<![CDATA[".$this->rawFieldContent."]]>";
}else{
if($this->truncSizeandis_int($this->truncSize)){
$result=FeedCreator::iTrunc(htmlspecialchars($this->rawFieldContent),$this->truncSize);
}else{
$result=htmlspecialchars($this->rawFieldContent);
}
}
return$result;
}
}
classUniversalFeedCreatorextendsFeedCreator{
var$_feed;
function_setFormat($format){
switch(strtoupper($format)){
case"2.0":
//fallthrough
case"RSS2.0":
$this->_feed=newRSSCreator20();
break;
case"0.91":
//fallthrough
case"RSS0.91":
$this->_feed=newRSSCreator091();
break;
default:
$this->_feed=newRSSCreator091();
break;
}
$vars=get_object_vars($this);
foreach($varsas$key=>$value){
//preventoverwritingofproperties"contentType","encoding";donotcopy"_feed"itself
if(!in_array($key,array("_feed","contentType","encoding"))){
$this->_feed->{$key}=$this->{$key};
}
}
}
functioncreateFeed($format="RSS0.91"){
$this->_setFormat($format);
return$this->_feed->createFeed();
}
functionsaveFeed($format="RSS0.91",$filename="",$displayContents=true){
$this->_setFormat($format);
$this->_feed->saveFeed($filename,$displayContents);
}
functionuseCached($format="RSS0.91",$filename="",$timeout=3600){
$this->_setFormat($format);
$this->_feed->useCached($filename,$timeout);
}
}
classFeedCreatorextendsHtmlDescribable{
var$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();
functionaddItem($item){
$this->items[]=$item;
}
functionclearItem2Null(){
$this->items=array();
}
functioniTrunc($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){
returnsubstr($string,0,$pos+1)."...";
}
$pos=strrpos($string,"");
if($pos>=$length-4){
$string=substr($string,0,$length-4);
$pos=strrpos($string,"");
}
if($pos>=$length*0.4){
returnsubstr($string,0,$pos)."...";
}
returnsubstr($string,0,$length-4)."...";
}
function_createGeneratorComment(){
return"<!--generator=\"".FEEDCREATOR_VERSION."\"-->\n";
}
function_createAdditionalElements($elements,$indentString=""){
$ae="";
if(is_array($elements)){
foreach($elementsAS$key=>$value){
$ae.=$indentString."<$key>$value</$key>\n";
}
}
return$ae;
}
function_createStylesheetReferences(){
$xml="";
if($this->cssStyleSheet)$xml.="<?xml-stylesheethref=\"".$this->cssStyleSheet."\"type=\"text/css\"?>\n";
if($this->xslStyleSheet)$xml.="<?xml-stylesheethref=\"".$this->xslStyleSheet."\"type=\"text/xsl\"?>\n";
return$xml;
}
functioncreateFeed(){}
function_generateFilename(){
$fileInfo=pathinfo($_SERVER["PHP_SELF"]);
returnsubstr($fileInfo["basename"],0,-(strlen($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();
}
functionuseCached($filename="",$timeout=3600){
$this->_timeout=$timeout;
if($filename==""){
$filename=$this->_generateFilename();
}
if(file_exists($filename)&&(time()-filemtime($filename)<$timeout)){
$this->_redirect($filename);
}
}
functionsaveFeed($filename="",$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>Errorcreatingfeedfile,pleasecheckwritepermissions.</b><br/>";
}
}
}
classFeedDate{
var$unix;
functionFeedDate($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($matches[7],0,1)=='+'ORsubstr($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)=='+'ORsubstr($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;
}
functionrfc822(){
$date=gmdate("Y-m-dH:i:s",$this->unix);
if(TIME_ZONE!="")$date.="".str_replace(":","",TIME_ZONE);
return$date;
}
functioniso8601(){
$date=gmdate("Y-m-dH:i:s",$this->unix);
$date=substr($date,0,22).':'.substr($date,-2);
if(TIME_ZONE!="")$date=str_replace("+00:00",TIME_ZONE,$date);
return$date;
}
functionunix(){
return$this->unix;
}
}
classRSSCreator10extendsFeedCreator{
functioncreateFeed(){
$feed="<?xmlversion=\"1.0\"encoding=\"".$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";
$feed.=" <channelrdf:about=\"".$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){
$feed.=" <imagerdf:resource=\"".$this->image->url."\"/>\n";
}
$now=newFeedDate();
$feed.=" <dc:date>".htmlspecialchars($now->iso8601())."</dc:date>\n";
$feed.=" <items>\n";
$feed.=" <rdf:Seq>\n";
for($i=0;$i<count($this->items);$i++){
$feed.=" <rdf:lirdf:resource=\"".htmlspecialchars($this->items[$i]->link)."\"/>\n";
}
$feed.=" </rdf:Seq>\n";
$feed.=" </items>\n";
$feed.=" </channel>\n";
if($this->image!=null){
$feed.=" <imagerdf:about=\"".$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++){
$feed.=" <itemrdf:about=\"".htmlspecialchars($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){
$itemDate=newFeedDate($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;
}
}
classRSSCreator091extendsFeedCreator{
var$RSSVersion;
functionRSSCreator091(){
$this->_setRSSVersion("0.91");
$this->contentType="application/rss+xml";
}
function_setRSSVersion($version){
$this->RSSVersion=$version;
}
functioncreateFeed(){
$feed="<?xmlversion=\"1.0\"encoding=\"".$this->encoding."\"?>\n";
$feed.=$this->_createGeneratorComment();
$feed.=$this->_createStylesheetReferences();
$feed.="<rssversion=\"".$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=newFeedDate();
$feed.=" <lastBuildDate>".htmlspecialchars($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!=""){
$pubDate=newFeedDate($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[$i]->author)."</author>\n";
}
/*
//onhold
if($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!=""){
$itemDate=newFeedDate($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;
}
}
classRSSCreator20extendsRSSCreator091{
functionRSSCreator20(){
parent::_setRSSVersion("2.0");
}
}使用示例：
<?php
header('Content-Type:text/html;charset=utf-8');
$db=mysql_connect('127.0.0.1','root','123456');
mysql_query("setnamesutf8");
mysql_select_db('dbname',$db);
$brs=mysql_query('select*fromarticleorderbyadd_timedesclimit0,10',$db);
$rss=newUniversalFeedCreator();
$rss->title="页面标题";
$rss->link="网址http://";
$rss->description="rss标题";
while($rowbrs=mysql_fetch_array($brs)){
$item=newFeedItem();
$item->title=$rowbrs['subject'];
$item->link='https://www.nhooo.com/';
$item->description=$rowbrs['description'];
$rss->addItem($item);
}
mysql_close($db);
$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。