PHP Cookbook, 2nd Edition

Chapter 16. Internet Services

Introduction

Before there was HTTP, there was FTP, NNTP, IMAP, POP3, and a whole alphabet soup of other protocols. Many people quickly embraced web browsers because the browser provided an integrated program that let them check their email, read newsgroups, transfer files, and view documents without worrying about the details surrounding the underlying means of communication. PHP provides functions, both natively and through PEAR, to use these other protocols. With them, you can use PHP to create web frontend applications that perform all sorts of network-enabled tasks, such as looking up domain names or sending web-based email. While PHP simplifies these jobs, it is important to understand the strengths and limitations of each protocol.

Recipes 16.1 to 16.3 cover the most popular feature of all: email. Recipe 16.1 shows how to send basic email messages. Recipe 16.2 describes MIME-encoded email, which enables you to send plain text and HTML-formatted messages. The IMAP and POP3 protocols, which are used to read mailboxes, are discussed in Recipe 16.3.

The next two recipes discuss how to read newsgroups with NNTP. Newsgroups are similar to mailing lists, but instead of every person on the list receiving an email message, people can access a news server and view just the messages they’re interested in. Newsgroups also allow threaded discussions, so its easy to trace a conversation through the archives. Recipe 16.4 discusses posting messages, while Recipe 16.5 ...