RESTful Web Services

Chapter 1. The Programmable Web and Its Inhabitants

When you write a computer program, you’re not limited to the algorithms you can think up. Your language’s standard library gives you some algorithms. You can get more from books, or in third-party libraries you find online. Only if you’re on the very cutting edge should you have to come up with your own algorithms.

If you’re lucky, the same is true for data. Some applications are driven entirely by the data the users type in. Sometimes data just comes to you naturally: if you’re analyzing spam, you should have no problem getting all you need. You can download a few public data sets—word lists, geographical data, lists of prime numbers, public domain texts—as though they were third-party libraries. But if you need some other kind of data, it doesn’t look good. Where’s the data going to come from? More and more often, it’s coming from the programmable web.

When you—a human being—want to find a book on a certain topic, you probably point your web browser to the URI of an online library or bookstore: say, http://www.amazon.com/.

Tip

The common term for the address of something on the Web is “URL.” I say “URI” throughout this book because that’s what the HTTP standard says. Every HTTP URI on the Web is also a URL, so you can substitute “URL” wherever I say “URI” with no loss of meaning.

You’re served a web page, a document in HTML format that your browser renders graphically. You visually scan the page for a search form, type your topic ...