Professional PHP4 will show you exactly how to create state of the art web applications that scale well, utilize databases optimally, and connect to a back-end network using a multi-tiered approach. This book also aims at teaching PHP by coding FTP clients, e-mail clients, some advanced data structures, session management, and secure programming. Topics covered: The whys and wherefores of PHP4; PHP installation on *nix, Windows, and MacOS X; Sessions and cookies, coding FTP clients, network-related function calls, and directory services; PHP support for LDAP; Multi-tiered development using PHP; PHP's interaction with XML; PHP with MySQL; PHP with PostgreSQL and ODBC; Securing, optimizing, and internationalizing PHP applications; PHP extension libraries; A real world employee directory, an online library application, and a GTK interface to the application; Case studies on a user privilege system and a multi-tiered WML-based shopping cart.