NetNewsWire/Safari Extension/evergreen-subscribe-to-feed.js

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var thisPageLinkObjects = null;
// I convert the native "link" node into an object that I can pass out to the global page
function objectFromLink(theLink) {
var linkObject = new Object();
linkObject.href = theLink.href;
linkObject.type = theLink.type;
linkObject.title = theLink.title;
return linkObject;
}
// Some sites will list feeds with inappropriate or at least less-than-ideal information
// in the MIME type attribute. We cover some edge cases here that allow to be passed through,
// where they will successfully open as "feed://" URLs in the browser.
function isValidFeedLink(theLink) {
var isValid = false;
switch (theLink.type)
{
case "application/atom+xml":
case "application/x.atom+xml":
case "application/rss+xml":
// These types do not require other criteria.
isValid = (theLink.href != null);
case "text/xml":
case "application/rdf+xml":
// These types require a title that has "RSS" in it.
if (theLink.title && theLink.title.search(/RSS/i) != -1)
{
isValid = (theLink.href != null);
}
}
return isValid;
}
function scanForSyndicationFeeds() {
// In case we don't find any, we establish that we have at least tried by setting the
// variables to empty instead of null.
thisPageLinkObjects = []
thisPageLinks = document.getElementsByTagName("link");
for (thisLinkIndex = 0; thisLinkIndex < thisPageLinks.length; thisLinkIndex++)
{
var thisLink = thisPageLinks[thisLinkIndex];
var thisLinkRel = thisLink.getAttribute("rel");
if (thisLinkRel == "alternate")
{
if (isValidFeedLink(thisLink))
{
thisPageLinkObjects.push(objectFromLink(thisLink));
}
}
}
}
function subscribeToFeed(theFeed) {
// Convert the URL to a feed:// scheme because Safari
// will refuse to load e.g. a feed that is listed merely
// as "text/xml". We do some preflighting of the link rel
// in the PageLoadEnd.js so we can be more confident it's a
// good feed: URL.
var feedURL = theFeed.href;
if (feedURL.match(/^http[s]?:\/\//))
{
feedURL = feedURL.replace(/^http[s]?:\/\//, "feed://");
}
else if (feedURL.match(/^feed:/) == false)
{
feedURL = "feed:" + feedURL;
}
safari.extension.dispatchMessage("subscribeToFeed", { "url": feedURL });
}
function messageHandler(event) {
if (event.name === "toolbarButtonClicked")
{
// Workaround Radar #31182842, in which residual copies of our
// app extension may remain loaded in context of pages in Safari,
// causing multiple responses to broadcast message about toolbar
// button being clicked. In the case of the "extra" injections,
// the document location is null, so we can avoid doing on anything.
if ((document.location != null) && (thisPageLinkObjects.length > 0))
{
feedToOpen = thisPageLinkObjects[0];
subscribeToFeed(feedToOpen);
}
}
else if (event.name === "ping")
{
// Just a hack to get the toolbar icon validation to work as expected.
// If we don't pong back, the extension knows we are not loaded in a page.
// There is a bug in Safari where the messageHandler is apparently held on to by Safari
// even after an extension is disabled. So an effort to "ping" an extension's scripts will
// succeed even if its been disabled and the page reloaded. Checking for the existance of
// document.location seems to ensure we have enough of a handle still on the document that
// we can do something useful with it.
var shouldValidate = (document.location != null) && (thisPageLinkObjects.length > 0);
// Pass back the same validationID we were handed so they can look up the correlated validationHandler
safari.extension.dispatchMessage("pong", { "validationID": event.message.validationID, "shouldValidate": shouldValidate });
}
}
document.addEventListener("DOMContentLoaded", function(event) {
// Prevent injecting the JavaScript in IFRAMES, and from acting before Safari is ready...
if ((window.top === window) && (typeof safari != 'undefined') && (document.location != null))
{
safari.self.addEventListener("message", messageHandler, false)
scanForSyndicationFeeds();
}
});