March 1996
Intermediate to advanced
450 pages
10h
English
Content preview from CGI Programming on the World Wide Web
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12. Debugging and Testing CGI Applications
The hardest aspect of developing CGI applications on the Web is the testing/debugging phase. The main reason for the difficulty is that applications are being run across a network, with client and server interaction. When there are errors in CGI programs, it is difficult to figure out where they lie.
In this chapter, we will discuss some of the common errors in CGI script design, and what you can do to correct them. In addition, we will look at a debugging/lint tool for CGI applications, called CGI Lint, written exclusively for this book.
12.1 Common Errors
Initially, we will discuss some of the simpler errors found in CGI application design. Most CGI designers encounter these errors at one time or another. However, they are extremely easy to fix.
CGI Script in Unrecognized Directory
Most servers require that CGI scripts reside in a special directory (/cgi-bin), or have certain file extensions. If you try to execute a script that does not follow the rules for a particular server, the server will simply retrieve and display the document, instead of executing it. For example, if you have the following two lines in your NCSA server resource map configuration file (srm.conf):
ScriptAlias /my-cgi-apps/ /usr/local/bin/httpd_1.4.2/cgi-bin/ AddType application/x-httpd-cgi .cgi .pl
the server will execute only scripts with URLs that either contain the string “/my-cgi-apps,” or have a file extension of .pl or .cgi. Take a look at the following ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.