Historically, a lot of technologies have been developed and used to create a client-server system. In recent decades, though, all client-server architectures tend to be web-based—that is, based on the HyperText Transfer Protocol (HTTP). HTTP is based on the Transfer Control Protocol (TCP) and the Internet Protocol (IP). In particular, two web-based architectures have become popular—the Simple Object Access Protocol (SOAP) and Representational State Transfer (REST).

While SOAP is an actual protocol, REST is only a collection of principles. The web services adhering to the REST principles are said to be RESTful. In this chapter, we'll see how to build RESTful services using the popular Actix web framework.

Any web service (REST web services included) can be used by any web client—that is, any program that can send HTTP requests...