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About the Author
Akash Mehta
Akash Mehta is a web developer and freelance writer specializing in web application development. Check out his other work at http://bitmeta.org/.
Learn Adobe AIR, Part III: Beyond the Browser
Whoever said that the desktop was dead? Large sites such as eBay make available desktop applications for their web services due to the fact that they’re often more stable, more lightweight, and provide a smoother user experience.
One of the big features of Adobe AIR is the rethink of Ajax—in particular, the cross-domain security restrictions. Before AIR, a web application could only make Ajax requests to the same domain from which it originated, with some exceptions. To fetch data from another domain, a server-side proxy script was needed to relay the request. In AIR, Adobe has enabled cross-domain Ajax requests to support the wide variety of potential uses of AIR applications that consume web services and interact with server-side applications. This opens the door for all sorts of handy mashups that operate entirely on the client side.
In this article, we’re going to look at consuming web services from a simple PHP application—we’ll work with login mechanisms, file uploads, and reading an RSS news feed. We’ll be building a simple interface to enable a firm’s clients to log in and submit files, as well as browse internal notices from the newsfeed.
Continuing our recent theme, there’ll be a quiz at the end, to test you on what you’ve learned. The first 100 people to undergo the quiz will receive, free-of-charge, the Adobe AIR For JavaScript Developers pocket guide in the post. Remember, the book can be downloaded free as a PDF, so get cracking!
NOTE: Background Knowledge
To gain the most from this tutorial, I suggest you read through my introductory HTML/Ajax AIR articles, Build a Customer Management App and Build a Note Storage App, or are at least comfortable with AIR and jQuery. We’ll be using the AIR SDK again, along with Aptana and jQuery. If you haven’t set these up already, I cover this process in my first article, under the section A Powerful Tool for Building AIR Apps. For the purposes of this example, you’ll also need access to a PHP-enabled web server. Alternatively, you can rewrite the trivial PHP routines in your server-side language of choice.
Starting with the Sample Project
To get ready to build the application, download the baseline project files. You’ll find a single HTML file with separate div elements for the key sections of the application interface—we’ll use jQuery to show and hide the relevant sections as needed. Open Aptana, and create a new project in the same directory that you extracted the baseline files, or use the “Existing Folder as New Project” in the File > Import dialog.
The archive also includes a folder named serverfiles—you’ll need to upload these files to a PHP-enabled web server if you want to modify and experiment with the backend. Alternatively, you can create your own with the instructions in this tutorial. For now, we’ll use a hosted demonstration copy of these files.
Within our new project, all the action happens within the index.html file. Here’s a screenshot of the file with all the sections revealed.
We’ll store all our behavior logic in the behavior.js JavaScript file.