Feedspider Dev Blog: Firefox OS Ho!

Last week, I was fairly busy due to other commitments and did not have much time to work on FeedSpider, but last Wednesday, I got a bit of exciting news – I had been accepted to the Firefox OS Apps on a Flame program!

In exchange for me committing to have an app ported and in the Firefox Marketplace within 30 days of receiving the device, they sent me a Flame developer phone to do hardware testing on. So, with that time limit in place, that moves Firefox OS up to be the priority development target! Fortunately, Enyo (with a little bit of Cordova to fill in the gaps) and Firefox OS play very nicely together, so I have had a productive week.

Since the Firefox OS UI is HTML5 based, I have only had to make minor tweaks to FeedSpider’s core (so far) to make it work. The big thing is that it doesn’t like cross-domain Ajax calls using JSON (instead of JSONP). Unfortunately, that is 99% of what FeedSpider does.

That being said, it’s not impossible. You just need to know the magic words, and ask for the right permissions for your app. In my case, the app needs to be privileged, and ask for the systemXHR permission, as described here.

The tricky part is that you also need to pass the parameter {mozSystem: true} to the XMLHTTPRequest when you create it. In Enyo, that is a little challenging, as you would typically call enyo,Ajax, which doesn’t appear to pass the parameters all the way down to XMLHTTPRequest. For another app that I was working on, I wound up having to call XMLHTTPRequest directly, rather than using enyo.Ajax. For FeedSpider, however, since I am using the prototype.js library to handle my AJAX calls, I just had to change prototype.js’s call to include the {mozSystem: true} parameter, and then everything worked. Now, I just have a couple of places to update where I have implemented my own XMLHTTPRequest handlers to work around webOS not handling puts and deletes properly.

The other bit is that it doesn’t allow you to use exec statements, so I had to toss out the JSON parser that I added in to parse articles after some characters were causing the default webOS parser to choke. On Firefox OS, this is an even simpler fix. The XMLHTTPRequest response object returns a pre-parsed responseJSON object, so I don’t even need to add the overhead of parsing the JSON. (Gecko FTW!)

As of right now, I only have a handful of things to still get working properly before the app is ready:

The add subscriptions page
A proper list for feeds and folders with refreshing and delete buttons
A proper list for articles with swipe to star and mark read/unread
OAuth (although it looks like Firefox OS will support this nicely – it’s just not a cross-platform solution)
Notifications (toast-style)
Various bug-fixes and cleanups (such as figuring out why the sharing menu won’t refresh properly)

Parts of this are a bit of a tall order, but I think that I can do it. And the Flame arrived yesterday, so the clock is ticking.

First boot on the emulator. At this point, the list of feeds and folders are loading correctly, but the articles aren’t due to the problematic JSON parser being blocked by the system.