Chapter 11: CGI/Perl Part I

Webpages Can Be

• Static
• Dynamic

Dynamic Technologies

• CGI: Common Gateway Interface
• ASP: Active Server Pages
• Java Applets

Perl

• Perl: Practical Extraction and Report Language
• perl.com
• activestate.com

A Script on Esus

• The script.
• Notice the .cgi extension of the file.
• Notice the permission settings required.
• Here is the source code.
• A web page that demonstrates linking to the script.

Running the Script from the Command Line

• To test a script for syntax errors: perl -c script1.cgi
• To execute a script: perl -w script1.cgi

Sending Data to a CGI Script

• View the source code of this example and look at the browser address bar.
• View the source code of this example and look at the browser address bar.
• Notice the key/value pairs.
• Notice how to send a blank character.

Parsing Data in a CGI Script

• Run this example and then look at the source code.
• Run this example.
• The CGI.pm (perl module) is part of the Standard Perl distribution.
• qw is the quote word function.
• :standard is an import tag that tells Perl to import just the standard features of CGI.pm.
• -debug is a pragma that tells the script to pause to allow information to be entered from the keyboard.
• Notice the param(key) function in the script.
• Notice some of the possibilities of the print function in the script.

Sending Multiple Data

• <a href="http://whatever?key1=value1&key2=value2">
• Notice the &.

Monday Exercise

• Work Review Questions 1 - 15 from Chapter 11. 3 points.
• Work a modified version of Exercise 11-4. Translate any five English words into two languages of your choice. Get the Perl script to run on esus. 5 points.

Submit the answers to the above questions via memory stick before lab ends.

Tuesday Exercise

I will give you the URL of an e-commerce site. Answer the following questions during lab today regarding this site. At the end of the lab, place your answers on the memory stick. 10 points.

1. What type of markup language does the homepage use?
2. Does the homepage validate? If not, mention the most common type of error.
3. List the web programming technologies that the homepage uses.
4. There is some glaring redundancy in the code that produces the homepage. Describe how this redundancy can be fixed.
5. List the various form elements and their type that appear on the homepage.
6. Explain at a high level where the moving image comes from.
7. Describe in detail one interesting thing that you learned by studying the page.
8. Where does the current weather information come from?
9. Besides things alluded to in previous questions, describe one other way in which the page can be improved.
10. What company designed the page? Describe one interesting thing about this company.