Core PHP Programming, Third Edition

28.6. Simulating HTTP Connections

When writing PHP scripts, it is not necessary to understand every detail of the HTTP protocol. I would be straying to include a treatise here, but you ought to have enough understanding so that you could simulate a connect by using telnet. You may know that Web servers listen on port 80 by default. HTTP is a text-based protocol, so it's not hard to telnet directly to a Web server and type a simple request. HTTP has several commands that should be familiar; GET and POST are used most often. HEAD is a command that returns just the headers for a request. Browsers use this command to test whether they really want to get an entire document.

It is especially helpful to simulate an HTTP connection when your script sends ...