Knowing What to Expect as Output

For many developers, the idea of a Web service is easy to grasp—knowing what to expect from it is hard. The output begins with a certain amount of raw data that you'll receive from the Web service. However, the raw data doesn't really define the Web service output completely. You also need to consider quantifiable components such as the input to the Web service and that data manipulation you'll perform. In addition, there are variant elements to the output, such as the timeliness of the data. Finally, you need to consider the intangible elements. The output has some value to you, but someone else will view the output in another way. Concepts such as relevancy are difficult to quantify or even define.

Google Web Services is no different from any other Web service when it comes to output. You'll provide input, receive raw data, manipulate that data in some way, and view the output—the result of everything you have done with the Web service. The following sections discuss various elements of Web service output as they relate to Google Web Services. These sections provide an overview—the book continues to explore the subject in other chapters. However, this is the starting point—the point at which you start to consider what to expect as output from your efforts.