PHP is a widely-used Open Source general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. Its syntax draws upon C, Java, and Perl, and is easy to learn. PHP runs on many different platforms and can be used as a standalone executable or as a module under a variety of Web servers. It has excellent support for databases, XML, LDAP, IMAP, Java, various Internet protocols, and general data manipulation, and is extensible via its powerful API. It is actively developed and supported by a talented and energetic international team. Numerous Open Source and commercial PHP-based application packages are available.
PEAR Session Handler stores PHP4 session information in a database so that it is not only faster to retrieve, but it can (generally) handle a much greater load, and is able to be safely shared between machines without significant performance penalty. By default, the PHP session handler uses text files to store session information. While this is fine for smaller sites, it does not scale well and a more robust approach is required for larger sites. Unlike database-specific alternatives, pearsession supports all PEAR databases including Interbase, Informix, mSQL, MySQL, MS SQL Server, PostgreSQL, Oracle, Sybase, and others via ODBC.
APD is a general purpose non-interactive PHP profiler/debugger that produces formatted strace/truss type reports. APD supports full stack backtraces via calls similar to croak() in Perl's carp. APD is a Zend Extension and is designed to provide timing with the minimal performance impact. APD supports varying levels of debugging and can be turned on/off in individual scripts.
PHP-Authentication works like the Tomcat authentication. You give the source to authenticate against (DB, file, XML-RPC, etc.) and the directories that shall be protected, and the class handles the rest. No including of any call to a class method on every page is necessary. You can also use it as if it were a standard Auth-class, using a call to "isLoggedIn" on every page that shall be protected.