Introduction

One of the nice features that you can add to your site to give added benefit to your visitors is a search engine. It can help users quickly track down the documents, files or pages on your site that contain keywords that interest them. And if your site contains a huge back-catalog of material or documents, the idea of installing a search engine soon becomes more than a nice feature it becomes essential.

If you have visited any of the commercial index sites, such as AltaVista, Infoseek or Lycos, you'll know how a search engine operates from the user's point of view. What is not so obvious is how you go about porting a search engine application to your Web server.

There are, however, many search engine applications available ranging in price from freeware right up to tens of thousands of dollars. The differences are not always as obvious as the price! In fact, if you search requirements are simple, you could use the Perl search script that I have covered in Chapter 14 (that will search for text in a list of named files). There are several commercial Web server applications that have a search engine supplied including Luckman, O'Reilly's WebSite, Microsoft IIS, Netscape and Process' Purveyor (see Chapter 5 for more details on Web software). Search engines work in a similar way: one part will index the documents on your site, the second part searches the index in response to any user query. It's easy to trace the ancestry of...