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How-to use RSS in WRT widgets

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Article Metadata
Compatibility
Platform(s): S60 3rd Edition FP 2
Symbian
Article
Created: forum-mrkt (03 Oct 2007)
Last edited: hamishwillee (10 Oct 2012)

Contents

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");
}
This page was last modified on 10 October 2012, at 08:46.
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