xml 制做 RSS 订阅源

首先制做一个 RSS 模板，模板的文件名是 feed.xml，代码以下：

<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0" xmlns:wfw="http://wellformedweb.org/CommentAPI/"></rss>

再就是用php文件从数据库读取数据并生成 RSS 文件，这里用一个数组模拟从数据库读取的数据：

<?php 
class Rss{
    protected $dom = null;
    protected $temp = './feed.xml';
    protected $rss = null;
    protected $title = '';
    protected $desc = '';
    protected $link = '';
    
    public function __construct(){
        $this->title = '物理学';
        $this->desc = '现代物理学';
        $this->link = 'http://mysql/rss.php';
        $this->dom = new DOMDocument('1.0','utf-8');
        $this->dom->load($this->temp);
        $this->rss = $this->dom->getElementsByTagName('rss')->item(0);
    }
    
    public function feed($arr){
        $this->createChannel();
        $channel = $this->dom->getElementsByTagName('channel')->item(0);
        foreach ($arr as $v){
            $channel->appendChild($this->createItem($v));
        }
        header('content-type:text/xml');
        echo $this->dom->savexml();
    }
    
    protected function createChannel(){
        $channel = $this->dom->createElement('channel');
        $channel->appendChild($this->createEle('title',$this->title));
        $channel->appendChild($this->createEle('link',$this->link));
        $channel->appendChild($this->createEle('description',$this->desc));
        $this->rss->appendChild($channel);
    }

    protected function createItem($arr){
        $item = $this->dom->createElement('item');
        foreach($arr as $k => $v){
            $item->appendChild($this->createEle($k,$v));
        }
        return $item;
    }
    
    protected function createEle($name,$value){
        $e=$this->dom->createElement($name);
        $t=$this->dom->createTextNode($value);
        $e->appendChild($t);
        return $e;
    }
}

$arr = array(
    array(
        'title'=>'牛顿力学',
        'link'=>'1',
        'description'=>'牛顿力学'
    ),
    array(
        'title'=>'相对论',
        'link'=>'1',
        'description'=>'爱因斯坦的相对论'
    )
    
);
$rss = new Rss;
$rss->feed($arr);
?>

最后在火狐下效果：