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Deploy Web 2.0 technologies to save time and ensure data accuracy

Level: Advanced

Norbert (Norb) R. Ryan, III (nryan@us.ibm.com), Software Engineer, IBM 14 Feb 2008

Let’s cut through the chatter and find out how a Web service and Asynchronous JavaScript + XML (Ajax) can improve an application, in this case a Ruby on Rails (RoR) application. This article shows you how to spruce up a common Web activity—entering a street address—with Ajax and a call to a Web service. Learn a few tricks to combining these fundamental Web 2.0 components.

A little background on the idea

The United States Postal Service (USPS) has made several Web services available (see the USPS Web tools sidebar). One of those Web services accepts a ZIP code and returns the corresponding city and state. In this example application, you make use of this CityStateLookupRequest to save the user some typing. This feature also gives you better address data in your database, because you reduce the chances of typing errors.

Prerequisites and assumptions

David Heinemeier Hansson, the ideological spirit and creator of Ruby on Rails, is a smart guy! In RoR, he implemented a number of great ideas, ideas that make developing Web applications much easier and, as a friend of mine remarked, “It makes programming fun again!” There’s little doubt in my mind that other frameworks and programming paradigms will espouse these ideas. However, this isn’t a tutorial on how to create an RoR application. (See the Resources section at the end of this article for links to good tutorials and reference information.)

The assumption here is that you’ve created an RoR application that has an HTML input form for an address (for example, 590 Madison Ave, New York, NY 10022). This Rails application also has a model named address and a corresponding database table.

Furthermore, let’s assume that you:

• Understand basic design principles of Web application development.
• Have created an RoR application.
• Understand the basic parts of an RoR application: ActiveSupport, ActiveRecord, ActionView, ActionController, Migrations, and so on.
• Have a database (like IBM® DB2® or MySQL) configured to work with the RoR application.
• Connect with users by anticipating their needs and know the importance of saving them time.

Table 1. Assuming you have an RoR application with these objects