Section 17.1. What Are Internet Clients?


17.1. What Are Internet Clients?

Before we take a look at these protocols, we first must ask, "What is an Internet client?" To answer this question, we simplify the Internet to a place where data are exchanged, and this interchange is made up of someone offering a service and a user of such services. You will hear the term "producer-consumer" in some circles (although this phrase is generally reserved for conversations on operating systems). Servers are the producers, providing the services, and clients consume the offered services. For any one particular service, there is usually only one server (process, host, etc.) and more than one consumer. We previously examined the client/server model, and although we do not need to create Internet clients with the low-level socket operations seen earlier, the model is an accurate match.

Here, we will look specifically at three of these Internet protocolsFTP, NNTP, and POP3and write clients for each. What you should take away afterward are being able to recognize how similar the APIs of all of these protocols arethis is done by design, as keeping interfaces consistent is a worthy causeand most importantly, the ability to create real clients of these and other Internet protocols. And even though we are only highlighting these three specific protocols, at the end of this chapter, you should feel confident enough to write clients for just about any Internet protocol.



Core Python Programming
Core Python Programming (2nd Edition)
ISBN: 0132269937
EAN: 2147483647
Year: 2004
Pages: 334
Authors: Wesley J Chun

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