Vessenger is an app that allows closed groups such as organizations, to chat and send documents to each other or to a central repository. People can be divided in groups so that they can share status updates or documents with just the required people. In some ways it is similar to yammer, but was to be based primarily on a desktop app.
We decide to use Titanium
Working in Titanium can be frustrating at times, and although it works pretty well, I had to spend a lot of time looking through the documentation. After some time, I realized that the docs for Tianium are not easy to understand, not particularly friendly and sometimes even incomplete.
I started working on Vessenger by doing most of the UI, the status message sending and retrieving, and getting a basic version of the chat feature working for demo purposes. The status updates was the easiest one to build, and I added the possibility to upload files within you status update. They can be any type of files, with images showing a thumbnail when seen by your colleagues. All the files live on Vessenger’s servers, which makes it very easy to retrieve information at a later date, just by looking at your (infinite) chat or status history.
Switching to Adobe Air
I then started working on the chat feature, which is where we noticed an issue with the repeated server polling we were doing: as well as being suboptimal on the server side, the was also a memory leak on the client side, which seemd to be caused by Titanium not properly closing and/or releasing the connection object, a problem compouded by the fact that Titanium has no method for explicitely closing a remote connection. As I was connecting to the server several times per second, the memory footprint of the application grew fairly quickly. After a lot a frustration trying to make it right, we decided the problem lay with Titanium and decided to switch to Adobe Air. Regretfully, the latest Air version is not supported on Linux anymore, but it’s possible to make the app the app compatible with Air 2.6 to get it to run properly on linux.
The memory used by the app could climb to 600Mb overnight…
The switch to Adobe air did not involve the complete rewrite I feared, as most of the code is compatible and I had created some abstractions for things like connecting to the API and storing data. Nevertheless, EncryptedLocalStorage is great: very easy to use and has all the features needed. My only problem with Adobe Air was the way it handled cookies: it basically did not, so I had to create that from scratch, storing the cookies in EcryptedLocalStorage and sending it explicitely with each and every request. In hindsight I should have setup a dedicated server with node.js to talk to the API, and socket.io to talk between the desktop app and the node server. I am actually implementing this solution now for another project and I think it would be a perfect fit for Vessenger as well.
Sort issues caused by Titanium
So by a combination of moving to Air and reducing the polling frequency for the things that did not need to be refreshed so often, I managed to eliminate the memory leak. Development could then continue as previously planned: I integrated Snaplr in the file upload dialogs, allowing the user to easily take a screenshot, annotate it and upload it along along with his message, to be seen instantly by the people he is chatting with. For me this is one of the killer features of Vessenger