Perl CGI Scripting

News Recommended Books Recommended Links Tutorials Reference CGI-scanners Selena Sol CGI scripts
CGI Security SSI Administration Debugging History Humor Etc.

CGI is a very flexible and powerful protocol, and it scales much more that most WEB developers assume.  CGI may be not that fancy technology, but it's simple and you can do almost anything it it.

The most common tool for writing CGI scripts is Perl, therefore most CGI scripts you can find on the WEB are written in this language.

Essentially, all web applications do pretty much the same things:

  1. Provide a Query Interface - Web Applications provide users with an interface for entering data. The data they enter is usually called a "query" or a "request" because the user-defined data is used to dynamically query or make a request from some service on the web server machine (searching a database, ordering a book, requesting a file).
  2. Transmit User-Defined Query - Once collected, the user-data is sent to a web server
  3. Perform Server Side Processing - The web server processes the user-data using some sort of "middleware".
  4. Massage Data - Processing almost always involves playing with data on the server. The user-defined request specifies how the data should be played with.
  5. Transmit Query Results - The processed data is now returned to the client.
  6. Perform Client Side Processing - Finally, the returned data is displayed to the user. Display might be as simple as interpreting HTML, or as complex as performing calculations, sorting, or other manipulations of the data.

 

News

Link To VerySimple Scripts -- nice collection of scripts

Installing Perl Modules on MS Windows Servers (the Easy Way)

WDVL Introduction to the Web Application Development Environment (Tools) by Selena Sol May 31, 1999

CGI Programming 101 - Learn CGI Today! online book. Average quality.

CGI Programming OpenFAQ

Web Client Programming with Perl -- online book

Table of Contents

Preface
Chapter 1: Introduction
Chapter 2: Demystifying the Browser
Chapter 3: Learning HTTP
Chapter 4: The Socket Library
Chapter 5: The LWP Library
Chapter 6: Example LWP Programs
Chapter 7: Graphical Examples with Perl/Tk

Appendix A: HTTP Headers
Appendix B: Reference Tables
Appendix C: The Robot Exclusion Standard

Index

Examples

 

General Web Scripting Tutorials

CGI Tutorial Start

Tutorial Documentation -- tutorial gateway -- Perl-based, very good idea

Perl Primer-CGI-Perl Tutorial

Webteacher.com - web database, javascript tutorial, cgi tutorial. An interactive site for helping non-programmers learn advanced web development skills. Great for beginners.

WDVL CGI The Common Gateway Interface for Server-side Processing

An instantaneous introduction to CGI scripts and HTML forms, Academic Computing Services, University of Kansas

CGI Script Tutorial and CGI Resources

Common Gateway Interface (CGI) Specifications
CGI-Resources Page
 CGI Tutorials and scripts
The Idiot's Guide to Solving Perl CGI Problems
Perl Tutotial Start
 CGI Scripts from NCSA
 ENMPC: Tutorial on CGI
Perl and CGI Tutorial
CGI Tutorial - Frames version
Matt's Perl Tutorial
Danny Aldham's Perl CGI Tutorial Page version 1.07
Perl and CGI Tutorial
CGI Tutorial && Link
CGI Tutorial: Start
CGI Manual
CGI & Perl links on the WWW
Perl-Related Links
CGI Tutorial: A simple CGI script
CGI Tutorial: What CGI scripts are

Recommended Links

***** CGI Resource Index. This is just Metaindex page: Archive and catalog of CGI scripts, documentation and resources.

Webteacher.com - web database, javascript tutorial, cgi tutorial. An interactive site for helping non-programmers learn advanced web development skills. Great for beginners.

WDVL CGI The Common Gateway Interface for Server-side Processing

An instantaneous introduction to CGI scripts and HTML forms, Academic Computing Services, University of Kansas

CGI Script Tutorial and CGI Resources

Reference

CGI scripts have access to 20 or so environment variables, such as QUERY_STRING and CONTENT_LENGTH mentioned on the main page. Here's the complete list at NCSA.

REQUEST_METHOD
The HTTP method this script was called with. Generally "GET", "POST", or "HEAD".
HTTP_REFERER
The URL of the form that was submitted. This isn't always set, so don't rely on it. Don't go invading people's privacy with it, neither.
PATH_INFO
Extra "path" information. It's possible to pass extra info to your script in the URL, after the filename of the CGI script. For example, calling the URL 
http://www.myhost.com/mypath/myscript.cgi/path/info/here

will set PATH_INFO to "/path/info/here". Commonly used for path-like data, but you can use it for anything.

SERVER_NAME
Your Web server's hostname or IP address (at least for this request).
SERVER_PORT
Your Web server's port (at least for this request).
SCRIPT_NAME
The path part of the URL that points to the script being executed. It should include the leading slash, but certain older Web servers leave the slash out. You can guarantee the leading slash with this line of Perl:
$ENV{'SCRIPT_NAME'}=~ s#^/?#/# ;

So the URL of the script that's being executed is, in Perl, 

"http://$ENV{'SERVER_NAME'}:$ENV{'SERVER_PORT'}$ENV{'SCRIPT_NAME'}"

The complete URL the script was invoked with may also have PATH_INFO and QUERY_STRING at the end.

MIME Types

MIME types are standard, case-insensitive strings that identify a data type, used throughout the Internet for many purposes. They start with the general type of data (like text, image, or audio), followed by a slash, and end with the specific type of data (like html, gif, or jpeg). HTML files are identified with text/html, and GIFs and JPEGs are identified with image/gif and image/jpeg. Here's a pretty good list of commonly-used MIME types.

CGI-scanners

whisker.txt

R a i n F o r e s t P u p p y

Whisker
Whisker is a CGI scanner with impressive features that makes it much better than most CGI scanners.

Download:
http://www.wiretrip.net/rfp/p/doc.asp?id=21&iface=2

 

CGI Scripts Archives

Perl 

HTTP Servers & Add-ons:

Common Gateway Interface (CGI) Specifications

CGI-Resources Page
CGI Tutorials and scripts


Perl Tutotial Start
 CGI Scripts from NCSA
 ENMPC: Tutorial on CGI
Perl and CGI Tutorial
CGI Tutorial - Frames version
Matt's Perl Tutorial
Danny Aldham's Perl CGI Tutorial Page version 1.07
Perl and CGI Tutorial
CGI Tutorial && Link
CGI Tutorial: Start
CGI Manual
CGI & Perl links on the WWW
Perl-Related Links
CGI Tutorial: A simple CGI script
CGI Tutorial: What CGI scripts are

Selena Sol

WDVL WebWare  -- A monthly column for the cultural anthropologist and other liberal arts hackers gone Webmaster

eXtropia free downloads

BigNoseBird.Com's Free perl CGI Scripts Archive Page 'The Strangest Name in Web Authoring Resources'. 14 useful Perl scripts including; a virtual greeting card script, survey script with instant colour results, domain name lookup & various search scripts. There are no demos are avalible for the scripts, but they are keen to help if you have any problems setting them up.

Selena Sol's Guestbook made a little easier by BigNoseBird.Com

Free CGI Scripts Page 1 of 2

CGI SCRIPT TUTORIALS

Debugging and Troubleshooting

The Idiot's Guide to Solving Perl CGI Problems

Debugging CGI Programs contains a useful script to help debug your CGI programs. Requires Apache Server v1.2.

Administration

Seite zum Thema Linux   --  SendingMirror.pl, a small script to keep your remote web server or ftp server up to date by pushing the changed data from your local host, maybe behind a firewall or a dialup line.

CGI Security

The problem with /usr/ucb/mail shell escapes is going stay with us for quite a while: I have found that many web sites run CGI helper scripts that send data from the network into /usr/ucb/mail, without censoring of, for example, newline characters embedded in the data.

Etc

 

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