Web services are getting a lot of hype. In the end, however, a Web service is just an HTTP request and response where each may be carrying XML data (Figure 28.1). So using a Web service from Cocoa is simply a matter of being able to send HTTP requests and receive responses and it also may require generating and parsing XML or JSON.
HTTP requests and responses are handled by
NSURLConnection (Figure 28.2).
Generating and parsing XML is typically done in one of two ways. The high-level method is to use ...