PHP - AJAX RSS Reader

Really Simple Syndication is used to publish often updated information from website like audio, video, images, etc. We can integrate RSS feeds to a website by using Ajax and php. This code demonstrates how to show RSS feeds in our site.

Ajax (Asynchronous JavaScript And XML) and RSS (Really Simple Syndication) are two technologies that have taken the Web by storm. Most commonly, RSS is used to provide news to either people or other organizations. This is done by serving an "RSS feed" from a website. An RSS feed is simply a link to an XML file that is structured in a certain way. The RSS specification tells us the expected structure of the XML file. For example, the title, author, and description tags are required, and so all RSS XML files will have at least these three tags.

Index.html

Index page should be as follows

Example -

<html>
   <head>
      
      <script>
         function showRSS(str) {
            if (str.length == 0) { 
               document.getElementById("output").innerHTML = "";
               return;
            }
         
            if (window.XMLHttpRequest) {
               xmlhttp = new XMLHttpRequest();
            }else {
               xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
            }
            xmlhttp.onreadystatechange = function() {
               if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
                  document.getElementById("output").innerHTML = xmlhttp.responseText;
               }
            }
            
            xmlhttp.open("GET","rss.php?q="+str,true);
            xmlhttp.send();
         }
      </script>
      
   </head>
   
   <body>
      <p>Please Select an option to get RSS:</p>
      
      <form>
         <select onchange = "showRSS(this.value)">
            <option value = "">Select an RSS-feed:</option>
            <option value = "cnn">CNN</option>
            <option value = "bbc">BBC News</option>
            <option value = "pc">PC World</option>
         </select>
      </form>
      <br>
      
      <div id = "output">RSS-feeds</div>
      
   </body>
</html>

This function simply calls the constructor of the RSS2Channel object and passes rssxml. This argument is of special significance, as it contains all of the RSS information. Moreover, JavaScript is able to recognize this as an XML object, and therefore we are able to use JavaScript's built-in DOM (Document Object Model) functions and properties on it. We can do this because we used the responseXML attribute of the XHR object to get the server response. If we had used responseText, parsing the XML would be much more difficult.

rss.php

rss.php has contained syntax about how to get access to rss feeds and return rss feeds to web pages.

Example -

<html>
   <head>
<?php
   $q = $_GET["q"];
   
   if($q == "cnn") {
      $xml = ("https://rss.cnn.com/rss/cnn_topstories.rss");
   }elseif($q == "bbc") {
      $xml = ("https://newsrss.bbc.co.uk/rss/newsonline_world_edition/americas/rss.xml");
   }elseif($q = "pcw"){
      $xml = ("https://www.pcworld.com/index.rss");
   }
	
   $xmlDoc = new DOMDocument();
   $xmlDoc->load($xml);
   
   $channel = $xmlDoc->getElementsByTagName('channel')->item(0);
   
   $channel_title = $channel->getElementsByTagName('title')
   ->item(0)->childNodes->item(0)->nodeValue;
   
   $channel_link = $channel->getElementsByTagName('link')
   ->item(0)->childNodes->item(0)->nodeValue;
   
   $channel_desc = $channel->getElementsByTagName('description')
   ->item(0)->childNodes->item(0)->nodeValue;
   
   echo("<p><a href = '" . $channel_link . "'>" . 
      $channel_title . "</a>");
   echo("<br>");
   echo($channel_desc . "</p>");
   
   $x = $xmlDoc->getElementsByTagName('item');
   
   for ($i = 0; $i<=2; $i++) {
      $item_title = $x->item($i)->getElementsByTagName('title')
      ->item(0)->childNodes->item(0)->nodeValue;
      
      $item_link = $x->item($i)->getElementsByTagName('link')
      ->item(0)->childNodes->item(0)->nodeValue;
      
      $item_desc = $x->item($i)->getElementsByTagName('description')
      ->item(0)->childNodes->item(0)->nodeValue;
      
      echo ("<p><a href = '" . $item_link . "'>" .
         $item_title . "</a>");
      echo ("<br>");
      echo ($item_desc . "</p>");
   }
?>
</body>
</html>