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How to generate RSS subscription in php_PHP tutorial

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Release： 2016-07-13 10:06:44
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How to generate RSS subscriptions in php

This article describes how to generate RSS subscriptions in php. Share it with everyone for your reference. The specific analysis is as follows:

RSS (Really Simple Syndication, also called syndication) is a format for describing and synchronizing website content. RSS can be one of the following three interpretations: Really Simple Syndication; RDF (Resource Description Framework) Site Summary; Rich Site Summary. But in fact, these three explanations all refer to the same Syndication technology. RSS is currently widely used in online news channels, blogs and wikis. Using RSS subscriptions can obtain information faster. The website provides RSS output, which is helpful for users to obtain the latest updates of website content. Network users can use aggregation tool software that supports RSS on the client to read website content that supports RSS output without opening the website content page.
Technically speaking, an RSS file is a piece of standardized XML data. The file generally has rss, xml or rdf as the suffix. The following is an example of the content of an rss file:

The code is as follows:




Script Home
http://www.jb51.net/
Script Home

RSS Tutorial
Website address/rss
New RSS tutorial on W3School


XML Tutorial
Website address/xml
New XML tutorial on W3School


The following is a code example that uses php to dynamically generate RSS:

The code is as follows:

/**
** PHP dynamically generates RSS classes
**/
define("TIME_ZONE","");
define("FEEDCREATOR_VERSION","www.jb51.net");//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){
$result="rawFieldContent."]]>";
}else{
if($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>$valuen";
}
}
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.= " $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";
$feed.= " ".$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.= " Postingn";
$feed.= " text/htmln";
if($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,"nr"," ")))."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");
}
}


使用示例：

代码如下:

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='http://www.jb51.net/';
$item->description =$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。

www.bkjia.comtruehttp://www.bkjia.com/PHPjc/958128.htmlTechArticlephp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）...
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