Aaron Crane - GBdirect Ltd.

Experiences of Using PHP in Large Websites

The PHP scripting language has enjoyed an enormous growth in popularity over the past few years. It benefits from being particularly easy to pick up and having been designed as a language just for producing webpages. As such, a dynamically-generated webpage can be implemented quickly in PHP.

This talk examines how well PHP scales for use in larger commercial websites. Issues covered include:

• The separation of presentation from business logic;
• Sharing code between pages in a site, and between sites;
• How cross-platform PHP is in practice;
• Having multiple developers working together on a site;
• Where PHP's simplicity can actually make things more complicated;
• Security considerations;
• Caveats that can trip you up between development and deployment;

Real-world examples are used to illustrate both the situations where PHP makes life easier, and those where it causes headaches or security holes. These are taken from our experiences using PHP in a range of sites, including the geographic search engine Somewherenear.com, and a multi-million dollar e-commerce site in the canning industry.

We have concluded that there are some circumstances in which it is not appropriate to use PHP, as it creates more problems than it solves. However, we do not go so far as to claim it should never be used. Rather, we have identified a checklist of pertinent questions for determining in advance how suitable PHP is for a given project - where it falls on the pain/gain axis. For circumstances where PHP is to be used, we present tips and guidance for doing so while keeping the suffering so caused to the minimum necessary - defensive coding techniques, which PHP configurations settings to use, which PHP features to avoid, and which security considerations to be aware of.