In this chapter, I discussed how to consume web APIs that use the XML-­RPC and SOAP/WSDL protocols. Although these protocols, especially SOAP and WSDL, are geared toward simplifying the process for making calls to web services, they sometimes are fragile in practice. Consequently, if you use them, you should learn how to debug them with the techniques I showed you in this chapter.

With techniques to work with REST, XML-­RPC, and SOAP web APIs in hand, you can then start moving beyond Flickr to look at a wide range of APIs. I showed you how to use to learn about those APIs and to draw some broad conclusions about APIs, the protocols they use, which ones are popular, and which subject matter they cover. I concluded this chapter with a study of the YouTube API (as an example of a simple REST API other than Flickr) and the Blogger API (as an instance of a uniform interface intimately tied to the HTTP methods). In the next chapter, you’ll study JavaScript-­based APIs and look at how to consume web APIs in the browser.