如何使用PHP写一个RSS订阅

<?xml version="1.0"?>
<rss version="2.0">
  <channel>
    <title>Liftoff News</title>
    <link>http://liftoff.msfc.nasa.gov/</link>
    <description>Liftoff to Space Exploration.</description>
    <language>en-us</language>
    <pubDate>Tue, 10 Jun 2003 04:00:00 GMT</pubDate>
    <lastBuildDate>Tue, 10 Jun 2003 09:41:01 GMT</lastBuildDate>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <generator>Weblog Editor 2.0</generator>
    <managingEditor>editor@example.com</managingEditor>
    <webMaster>webmaster@example.com</webMaster>
    <item>
      <title>Star City</title>
      <link>http://liftoff.msfc.nasa.gov/news/2003/news-starcity.asp</link>
      <description>How do Americans get ready to work with Russians aboard the
        International Space Station? They take a crash course in culture, language
        and protocol at Russia's Star City.</description>
      <pubDate>Tue, 03 Jun 2003 09:39:21 GMT</pubDate>
      <guid>http://liftoff.msfc.nasa.gov/2003/06/03.html#item573</guid>
    </item>
    
    <item>
      <title>Space Exploration</title>
      <link>http://liftoff.msfc.nasa.gov/</link>
      <description>Sky watchers in Europe, Asia, and parts of Alaska and Canada
        will experience a partial eclipse of the Sun on Saturday, May 31st.</description>
      <pubDate>Fri, 30 May 2003 11:06:42 GMT</pubDate>
      <guid>http://liftoff.msfc.nasa.gov/2003/05/30.html#item572</guid>
    </item>
    
    <item>
      <title>The Engine That Does More</title>
      <link>http://liftoff.msfc.nasa.gov/news/2003/news-VASIMR.asp</link>
      <description>Before man travels to Mars, NASA hopes to design new engines
        that will let us fly through the Solar System more quickly.  The proposed
        VASIMR engine would do that.</description>
      <pubDate>Tue, 27 May 2003 08:37:32 GMT</pubDate>
      <guid>http://liftoff.msfc.nasa.gov/2003/05/27.html#item571</guid>
    </item>
    
    <item>
      <title>Astronauts' Dirty Laundry</title>
      <link>http://liftoff.msfc.nasa.gov/news/2003/news-laundry.asp</link>
      <description>Compared to earlier spacecraft, the International Space
        Station has many luxuries, but laundry facilities are not one of them.
        Instead, astronauts have other options.</description>
      <pubDate>Tue, 20 May 2003 08:56:02 GMT</pubDate>
      <guid>http://liftoff.msfc.nasa.gov/2003/05/20.html#item570</guid>
    </item>
  </channel>
</rss>

<?php
$database =  "nameofthedatabase";
$dbconnect = mysql_pconnect(localhost, dbuser, dbpassword);
mysql_select_db($database, $dbconnect);
$query = "select link, headline, description from `headlines` limit 15";
$result = mysql_query($query, $dbconnect);
while ($line = mysql_fetch_assoc($result))
        {
            $return[] = $line;
        }
$now = date("D, d M Y H:i:s T");
$output = "<?xml version="1.0"?>
            <rss version="2.0">
                <channel>
                    <title>Our Demo RSS</title>
                    <link>http://www.tracypeterson.com/RSS/RSS.php</link>
                    <description>A Test RSS</description>
                    <language>en-us</language>
                    <pubDate>$now</pubDate>
                    <lastBuildDate>$now</lastBuildDate>
                    <docs>http://someurl.com</docs>
                    <managingEditor>you@youremail.com</managingEditor>
                    <webMaster>you@youremail.com</webMaster>
            ";
            
foreach ($return as $line)
{
    $output .= "<item><title>".htmlentities($line['headline'])."</title>
                    <link>".htmlentities($line['link'])."</link>
                    
<description>".htmlentities(strip_tags($line['description']))."</description>
                </item>";
}
$output .= "</channel></rss>";
echo $output;
?>

<?xml version="1.0"?>
    <rss version="0.97">
        <channel>
            <title>Our Demo RSS</title>
            <link>http://www.tracypeterson.com/RSS/RSS.php</link>
            <description>A Test RSS</description>
            <language>en-us</language>
            <pubDate>Mon, 13 Nov 2006 22:46:06 PST</pubDate>
            <lastBuildDate>Mon, 13 Nov 2006 22:46:06 PST</lastBuildDate>
            <docs>http://someurl.com</docs>
            <managingEditor>you@youremail.com</managingEditor>
            <webMaster>you@youremail.com</webMaster>
    <item rdf:about="http://www.tracypeterson.com/">
            <title>This is Tracy's Web Page!</title>
            <link>http://www.tracypeterson.com/</link>
            <description>This is a demonstration of how to get PHP to work for 
your RSS feed.</description>
        </item><item rdf:about="http://www.tracypeterson.com">
            <title>This is Tracy's site again!</title>
            <link>http://www.tracypeterson.com</link>
            <description>Again, this is a demonstration of the power of PHP 
coupled with RSS.</description>
        </item></channel></rss> 

<?php
require_once "XML/RSS.php";
$rss =& new XML_RSS("http://www.tracypeterson.com/RSS/RSS.php");
$rss->parse();
echo "<h1>Headlines from <a
href="http://www.tracypeterson.com/RSS/RSS.php">Tracy 
        Peterson's Site</a></h1>n"; echo "<ul>n";
foreach ($rss->getItems() as $item) {
  echo "<li><a href="" . $item['link'] . "">" . $item['title'] . 
"</a></li>n";
}
echo "</ul>n";
?>

foreach ($rss->getItems() as $item) {
  echo "<li>" . $item['title'] . 
"</li><br>";
  echo $item['description'] . "<br><br>n"; }