Opening tabs in Chrome news reader extension - google-chrome-extension

Question

I'm trying to create a simple chrome extension using the following google RSS reader sample,
http://code.google.com/chrome/extensions/samples.html#597015d3bcce3da693b02314afd607bec4f55291
I can add links in the pop-up window that open tabs, but not from the feeds themselves.
Looping through the items in the feed, grabbing title tags and link tags, I want the title to link the the appropriate sites
var entries = doc.getElementsByTagName('item');
var count = Math.min(entries.length, maxFeedItems);
for (var i = 0; i < count; i++) {
item = entries.item(i);
// Grab the title for the feed item.
var itemTitle = item.getElementsByTagName('title')[0];
if (itemTitle) {
itemTitle = itemTitle.textContent;
} else {
itemTitle = "Unknown title";
}
// Grab the link for this feed item
var itemLink = item.getElementsByTagName('link')[0];
if (itemLink) {
itemLink = itemLink.textContent;
} else {
itemLink = "Unknown link";
}
var title = document.createElement("a");
title.className = "item_title";
title.innerText = itemTitle; //display title in iframe
title.addEventListener("click", titleLink); // should open link when clicking on title, but does not.
}
// -------------------------------------------------------------------
// Show |url| in a new tab.
function showUrl(url) {
// Only allow http and https URLs.
if (url.indexOf("http:") != 0 && url.indexOf("https:") != 0) {
return;
}
chrome.tabs.create({url: url});
}
function moreStories(event) {
showUrl(moreStoriesUrl);
}
function titleLink(event) {
showUrl(itemLink);
}
Any thoughts on why this is not working.
If I replace title.addEventListener("click", titleLink); with title.addEventListener("click", moreStories); each title will link to moreStories, I cannot get each title to link to itemLink.
Thanks

Answer 1

Its a bit hard to answer your question without the whole code, but Ill give it a shot ;)
First up, titleLink() isnt going to work because itemLink isnt known. When you create title (the link) you should of attached it to that...say title.href=itemLink then in tiltleLinks you could access that href with showUrl(event.currentTarget.href)
Also did you fix the error in that example?...if not then change frameLoaded to....
function frameLoaded() {
var links = document.getElementsByTagName("A");
for (i = 0; i < links.length; i++) {
var clssName = links[i].className;
if (clssName != "item_title" && clssName != "open_box") {
links[i].addEventListener("click", showStory);
}
}
window.addEventListener("message", messageHandler);
}
If you still have probs could you attach the whole code so I can see what your doing and Ill give you a hand.

Answer 2

Thank you very much for your help.
code title.href=itemLink and code showUrl(event.currentTarget.href) was exactly what I needed.
For completeness, here is the full code,
<script id="iframe_script">
function reportHeight() {
var msg = JSON.stringify({type:"size", size:document.body.offsetHeight});
parent.postMessage(msg, "*");
}
function frameLoaded() {
var links = document.getElementsByTagName("A");
for (i = 0; i < links.length; i++) {
var class = links[i].className;
if (class != "item_title" && class != "open_box") {
links[i].addEventListener("click", showStory);
}
}
window.addEventListener("message", messageHandler);
}
function showStory(event) {
var href = event.currentTarget.href;
parent.postMessage(JSON.stringify({type:"show", url:href}), "*");
event.preventDefault();
}
function messageHandler(event) {
reportHeight();
}
</script>
<script>
// Feed URL.
var feedUrl = 'http://localhost/newsfeed.xml';
// The XMLHttpRequest object that tries to load and parse the feed.
var req;
function main() {
req = new XMLHttpRequest();
req.onload = handleResponse;
req.onerror = handleError;
req.open("GET", feedUrl, true);
req.send(null);
}
// Handles feed parsing errors.
function handleFeedParsingFailed(error) {
var feed = document.getElementById("feed");
feed.className = "error";
feed.innerText = "Error: " + error;
}
// Handles errors during the XMLHttpRequest.
function handleError() {
handleFeedParsingFailed('Failed to fetch RSS feed.');
}
// Handles parsing the feed data we got back from XMLHttpRequest.
function handleResponse() {
var doc = req.responseXML;
if (!doc) {
handleFeedParsingFailed("Not a valid feed.");
return;
}
buildPreview(doc);
}
// The maximum number of feed items to show in the preview.
var maxFeedItems = 10;
// Where the more stories link should navigate to.
var moreStoriesUrl;
function buildPreview(doc) {
// Get the link to the feed source.
var link = doc.getElementsByTagName("link");
var parentTag = link[0].parentNode.tagName;
if (parentTag != "item" && parentTag != "entry") {
moreStoriesUrl = link[0].textContent;
}
// Setup the title image.
var images = doc.getElementsByTagName("image");
var titleImg;
if (images.length != 0) {
var urls = images[0].getElementsByTagName("url");
if (urls.length != 0) {
titleImg = urls[0].textContent;
}
}
var img = document.getElementById("title");
// Listen for mouse and key events
if (titleImg) {
img.src = titleImg;
if (moreStoriesUrl) {
document.getElementById("title_a").addEventListener("click",moreStories);
document.getElementById("title_a").addEventListener("keydown",
function(event) {
if (event.keyCode == 13) {
moreStories(event);
}});
}
} else {
img.style.display = "none";
}
// Construct the iframe's HTML.
var iframe_src = "<!doctype html><html><head><script>" +
document.getElementById("iframe_script").textContent + "<" +
"/script></head><body onload='frameLoaded();' " +
"style='padding:0px;margin:0px;'>";
var feed = document.getElementById("feed");
// Set ARIA role indicating the feed element has a tree structure
feed.setAttribute("role", "tree");
var entries = doc.getElementsByTagName('item');
var count = Math.min(entries.length, maxFeedItems);
for (var i = 0; i < count; i++) {
item = entries.item(i);
// Grab the title for the feed item.
var itemTitle = item.getElementsByTagName('title')[0];
if (itemTitle) {
itemTitle = itemTitle.textContent;
} else {
itemTitle = "Unknown title";
}
// Grab the link for the feed item.
var itemLink = item.getElementsByTagName('link')[0];
if (itemLink) {
itemLink = itemLink.textContent;
} else {
itemLink = "Unknown link";
}
var item = document.createElement("div");
var title = document.createElement("a");
title.innerText = itemTitle; //display title in iframe
title.href=itemLink;
title.addEventListener("click", titleLink);
item.appendChild(title);
feed.appendChild(item);
}
if (moreStoriesUrl) {
var more = document.createElement("a");
more.className = "more";
more.innerText = "***Site Main Page*** \u00BB";
more.tabIndex = 0;
more.addEventListener("click", moreStories);
more.addEventListener("keydown", function(event) {
if (event.keyCode == 13) {
moreStories(event);
}});
feed.appendChild(more);
}
}
// -------------------------------------------------------------------
// Show |url| in a new tab.
function showUrl(url) {
// Only allow http and https URLs.
if (url.indexOf("http:") != 0 && url.indexOf("https:") != 0) {
return;
}
chrome.tabs.create({url: url});
}
// -------------------------------------------------------------------
function moreStories(event) {
showUrl(moreStoriesUrl);
}
function titleLink(event) {
showUrl(event.currentTarget.href);
}
function keyHandlerShowDesc(event) {
// Display content under heading when spacebar or right-arrow pressed
// Hide content when spacebar pressed again or left-arrow pressed
// Move to next heading when down-arrow pressed
// Move to previous heading when up-arrow pressed
if (event.keyCode == 32) {
showDesc(event);
} else if ((this.parentNode.className == "item opened") &&
(event.keyCode == 37)) {
showDesc(event);
} else if ((this.parentNode.className == "item") && (event.keyCode == 39)) {
showDesc(event);
} else if (event.keyCode == 40) {
if (this.parentNode.nextSibling) {
this.parentNode.nextSibling.children[1].focus();
}
} else if (event.keyCode == 38) {
if (this.parentNode.previousSibling) {
this.parentNode.previousSibling.children[1].focus();
}
}
}
function showDesc(event) {
var item = event.currentTarget.parentNode;
var items = document.getElementsByClassName("item");
for (var i = 0; i < items.length; i++) {
var iframe = items[i].getElementsByClassName("item_desc")[0];
if (items[i] == item && items[i].className == "item") {
items[i].className = "item opened";
iframe.contentWindow.postMessage("reportHeight", "*");
// Set the ARIA state indicating the tree item is currently expanded.
items[i].getElementsByClassName("item_title")[0].
setAttribute("aria-expanded", "true");
iframe.tabIndex = 0;
} else {
items[i].className = "item";
iframe.style.height = "0px";
// Set the ARIA state indicating the tree item is currently collapsed.
items[i].getElementsByClassName("item_title")[0].
setAttribute("aria-expanded", "false");
iframe.tabIndex = -1;
}
}
}
function iframeMessageHandler(e) {
// Only listen to messages from one of our own iframes.
var iframes = document.getElementsByTagName("IFRAME");
for (var i = 0; i < iframes.length; i++) {
if (iframes[i].contentWindow == e.source) {
var msg = JSON.parse(e.data);
if (msg) {
if (msg.type == "size") {
iframes[i].style.height = msg.size + "px";
}
else if (msg.type == "show") {
var url = msg.url;
if (url.indexOf("http://localhost/index.html") == 0) {
// If the URL is a redirect URL, strip of the destination and go to
// that directly. This is necessary because the Google news
// redirector blocks use of the redirects in this case.
var index = url.indexOf("&url=");
if (index >= 0) {
url = url.substring(index + 5);
index = url.indexOf("&");
if (index >= 0)
url = url.substring(0, index);
}
}
showUrl(url);
}
}
return;
}
}
}
window.addEventListener("message", iframeMessageHandler);
</script>
Thanks again for the help.
-Mike