Understanding Connectivity Requirements

You must consider three kinds of connectivity when you set up your development system. The first level of connectivity is your own machine. Make sure your machine has a connection to the Internet. Otherwise, any tests you run will fail. Remember that a Web service runs on the remote machine, not your local machine. You're borrowing the resources of that remote machine to perform useful work.

The second level of connectivity is the user's machine. If you create a Web site that simply contains links to Google's Web site, you can assume the user has a connection, but how fast is that connection? The best Web sites I've seen ask about the user's connection speed. This question allows the application to send the user the level of information that their connection can comfortably support. If you know that most users will rely on a dial-up connection for your Web site, make sure you also use a dial-up connection for testing. This additional step can greatly reduce the chances that you'll make the application too robust. Users who leave your site and don't use your application are users who are probably visiting someone else.

The third level of connectivity is the non-connected mode. You need to consider what happens when the user loses the connection or doesn't have one available. Applications can store static data locally to enable the user to continue using data they have already queried from the Web service. However, you need to observe any refresh requirements and ensure the data retains the same information the user would see online. For example, the local copy of the data must include any required copyright statements or trademarks.

Note Google's licensing terms are flexible in that they allow you to store information as long as that information remains viable to you and you retain your relationship with Google. This flexibility means you can create user applications that only query Google when necessary, instead of for each request. It's important to note that any application you create using Google Web Services will require your license to access the site. Any queries a user makes using your application will count against your licensed access total for the day. The best policy is to ensure the user obtains a personal license from Google whenever possible. Your application can request this license information from the user so the user's access doesn't count against your total.