About the Book
Table of Contents
Foreword
Preface
Source Code
Sample Chapters
About The Authors
Errata (typos, etc..)
Contact the Authors
Kevin
Brent
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Writing CGI Applications with Perl - Foreword
Foreword - Lincoln Stein When the Web exploded in popularity in the mid-90's, sweeping away Gopher, WAIS, Hyper-G and other competing technologies, a big part of its phenomenal success was the ease with which developers could attach backend processing to pretty front-end Web pages. Rather than offering an arcane programmer's interface to a limited number of programming languages, the Web offered the Common Gateway Interface, or CGI. CGI is the vice grip of the Internet. It is language-independent, platform-neutral, and best of all, easy to learn. You can write a CGI script to generate a dynamic Web page in just a couple of lines of code, and with not much more work you can accept user input from a fill-out form, pass it to a backend program or database for processing, and generate a new Web page to show the results. CGI allows you to take any new or legacy application and wrench it into a form that can be served over the Web. Almost from the start CGI was associated with the Perl programming language. In fact, to many people CGI is synonymous with Perl and vice versa. There are good reasons for this. If CGI is the vice grip of the Internet, then Perl is its duct tape. Perl's interprocess communications abilities couple with its powerful text parsing facilities to create an environment that makes it easy to combine unrelated software components into a seamless whole. For example, a typical e-commerce site needs to interface to a search engine, display catalog pages using up-to-date price information contained in a database, manage a shopping cart, and handle order entry, credit card validation, and order fulfillment. Perl excels that this type of task. It can run the search engine and transform its output into a hyperlinked web page, generate on-the-fly catalog pages from information contained in the stock database, transmit credit card information across the network to a verification service, and enter the user's order into the fulfillment database. The range of innovative applications that people have built on top of Perl/CGI is nothing short of amazing. Tourism agencies use Perl/CGI to generate interactive maps of cities and towns. Medical schools use Perl/CGI to run interactive simulations of human physiology. The human genome project uses Perl/CGI to share its vast holdings of mapping and sequencing data with the biological research community. Perl/CGI has also been used to glue a vast array of hardware devices to the Web -- everything from fish-cams to robotic arms. The Web has gotten a lot more complicated over the years. It's no longer sufficient just to accept user input from a fill-out form and generate an HTML pages in response. Web sites must be prepared to parse XML, generate XHTML and DHTML, manipulate cookies, and interact with increasingly distributed back-end systems. Users also have heightened expectations for the Web site experience. Users expect Web sites to remember them from visit to visit, and to allow them to customize the site to meet their particular needs. Thankfully, as the Web has evolved, Perl and CGI have grown to meet the challenges. This book demonstrates just how potent and vital the combination of Perl and CGI remains. In these pages you will learn how to glue Web pages to databases, track uers' click trails, exchange information with other sites using XML, and generate graphics and animations on the fly. Just as importantly, this book focuses from the outself on three issues that are often ignored in the pell-mell pace of Web development: security, reliability and scalability. I know that you'll find the combination of Perl and CGI to be both powerful and enjoyable, as I have over many years.
Lincoln Stein |