P.3. What You Need to Know

This book is not meant for people building their first dynamic web site. There are plenty of good books for first timers, so we won't be attempting to cover that ground here. As such, you'll need to have a little experience with building dynamic web sites or applications. At a minimum you should have a little experience of exposing data for editing via web pages and managing user data.

While this book isn't aimed solely at implementers, there are a number of practical examples. To fully appreciate these examples, a basic knowledge of programming is required. While you don't need to know about continuations or argument currying, you'll need to have a working knowledge of simple control structures and the basic von Neumann input-process-storage-output model.

Along with the code examples, we'll be looking at quite a few examples on the Unix command line. Having access to a Linux box (or other Unix flavor) will make your life a lot easier. Having a server on which you can follow along with the commands and code will make everything easier to understand and have immediate practical usage. A working knowledge of the command line is assumed, so I won't be telling you how to launch a shell, execute a command, or kill a process. If you're new to the command line, you should pick up an introductory book before going much further—command-line experience is essential for Unix-based applications and is becoming more important even for Windows-based applications.

While the techniques in this book can be equally applied to any number of modern technologies, the examples and discussions will deal with a set of four core technologies upon which many of the largest applications are built. PHP is the main glue language used in most code examples—don't worry if you haven't used PHP before, as long as you've used another C-like language. If you've worked with C, C++, Java?, JavaScript, or Perl, then you'll pick up PHP in no time at all and the syntax should be immediately understandable.

For secondary code and utility work, there are some examples in Perl. While Perl is also usable as a main application language, it's most capable in a command-line scripting and data-munging role, so it is often the sensible choice for building administration tools. Again, if you've worked with a C-like language, then Perl syntax is a cinch to pick up, so there's no need to run off and buy the camel book just yet.

For the database component of our application, we'll focus primarily on MySQL, although we'll also touch on the other big three (Oracle, SQL Server, and PostgreSQL). MySQL isn't always the best tool for the job, but it has many advantages over the others: it's easy to set up, usually good enough, and probably most importantly, free. For prototyping or building small-scale applications, MySQL's low-effort setup and administration, combined with tools like phpMyAdmin (http://www.phpmyadmin.net), make it a very attractive choice. That's not to say that there's no space for other database technologies for building web applications, as all four have extensive usage, but it's also important to note that MySQL can be used for large scale applications—many of the largest applications on the Internet use it. A basic knowledge of SQL and database theory will be useful when reading this book, as will an instance of MySQL on which you can play about and connect to example PHP scripts.

To keep in line with a Unix environment, all of the examples assume that you're using Apache as an HTTP server. To an extent, Apache is the least important component in the tool chain, since we don't talk much about configuring or extending it (that's a large field in itself). While experience with Apache is beneficial when reading this book, it's not essential. Experience with any web server software will be fine.

Practical experience with using the software is not the only requirement, however. To get the most out of this book, you'll need to have a working knowledge of the theory behind these technologies. For each of the core protocols and standards we look at, I will cite the RFC or specification (which tends to be a little dry and impenetrable) and in most cases refer to important books in the field. While I'll talk in some depth about HTTP, TCP/IP, MIME, and Unicode, other protocols are referred to only in passing (you'll see over 200 acronyms). For a full understanding of the issues involved, you're encouraged to find out about these protocols and standards yourself.