How-to use RSS in WRT widgets

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Article Metadata

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Compatibility

Platform(s): S60 3rd Edition FP 2

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Article

Created: forum-mrkt (03 Oct 2007)

Last edited: hamishwillee (10 Oct 2012)

Example code

This is example contains JavaScript example code for parsing RSS feed. As such RSS parsing is done using standard JavaScript functions - however developers should take into account the possibility of error conditions specific to mobile devices:

• No SIM inserted
• No access point available
• Connection canceled by the end user

request

function loadRSSFeed(url) {
  if (null == req) {
    req = new XMLHttpRequest();
  }  	
 
  req.onreadystatechange = ReqStateChange;
 
  req.open("GET", url, true);
  req.send(null); 
 
  document.getElementById("content").innerHTML = "Updating" + url; 
}

request callback

function ReqStateChange() {
  if (req.readyState == 4) {
 
    if (req.status == 200) {
    	UpdateContent(req);
    } 
    else {
      /*
       * if widget is totally dependent of network connection you 
       * might consider notifying end user. error may occur due to 
       * network error (GSM/3G), no SIM inserted, invalid access point etc.
       * detailed information is not available.
       */
      alert("error");
    }
  }
}

RSS parser

function UpdateContent(reqst) {
  var d = null;
  var el = document.getElementById("content");
 
  document.getElementById("content").innerHTML = "Updating!";
 
  var rss = null;
 
  var html = "";
  rss = reqst.responseXML.documentElement;
 
  if (rss != null) {
    var itemTitleNodes = rss.getElementsByTagName("title");
    var itemLinkNodes = rss.getElementsByTagName("link");
    var itemDescNodes = rss.getElementsByTagName("description");
 
    var c=itemTitleNodes.length;
 
    el.innerHTML="Displaying " + c + " items...";
 
    if (c<=0) {
      return;
    };
 
    if (c>4) c=3; // limit to four stories
 
    for (var i = 0; i < c; i++) { 
      var itemLink, itemTitle, itemDesc;
 
      if ((itemTitleNodes[i+2].childNodes[0] != null) &&
	  (itemLinkNodes[i+2].childNodes[0] != null) &&
	  (itemDescNodes[i+1].childNodes[0] != null)) {
 
        itemTitle = itemTitleNodes[i+2].childNodes[0].nodeValue;
	itemLink = itemLinkNodes[i+2].childNodes[0].nodeValue;
	itemDesc = itemDescNodes[i+1].childNodes[0].nodeValue;
      }
      else {
        itemTitle = "RSS feed missing";
	itemLink = "???";
	itemDesc = "RSS broken";
      }
      html = html + "<div class='item'><div class='linking'
      onClick='widget.openURL(\"" + itemLink +
      "\");'>"+itemTitle+"</div></br><div
      class='description'>"+itemDesc+"</div></div></br>";
    }
  }
 
  el.innerHTML = html;
  html = null;
  el = null;
  req = null;
 
  d = document.getElementById("lastupdate");		
}