Welcome to CGI PERL Tutorial

Introduction

Chapter 1   An Introduction to CGI and Its Environment

• The Common Gateway Interface (CGI)
• HTML, HTTP, and Your CGI Program
  • The Role of HTML
  • The HTTP Headers
  • Your CGI Program
• The Directories on Your Server
  • The Server Root
  • The Document Root
• File Privileges, Permissions, and Protection
• WWW Servers
  • MS-Based Servers
  • The CERN Server
  • The ncSA Server
  • The Netscape Server
• The CGI Programming Paradigm
  • CGI Programs and Security
  • The Basic Data-Passing Methods of CGI
  • CGI's Stateless Environment
• Preventing the Most Common CGI Bugs
  • Tell the Server Your File Is Executable
  • Finding Things on Your System
  • Make Your Program Executable
• Learning Perl
  • Hello World
  • Exercise 1.1. Working with Perl variables
  • Exercise 1.2. Using the scalar variable
• Summary
• Q&A

Chapter 2   Understanding How the Server and Browser Communicate

• Using the Uniform Resource Identifier
  • The Protocol
  • The Domain Name
  • The Directory, File, or CGI Program
• Requesting Your Web Page with the Browser
• Using the Internet Connection
  • TCP/IP, the Public Socket, and the Port
  • One More Time, Using the Switchboard Analogy
• Using the HTTP Headers
  • Status Codes in Response Headers
  • The Method Request Header
  • The Full Method Request Header
  • The Accept Request Header
  • The HTTP Response Header
• Changing the Returned Web Page Based on the User-Agent Header
• Learning Perl
  • Exercise 2.2. Using the Perl regular array
  • Exercise 2.3. Using Perl's associative array
• Summary
• Q&A

Chapter 3   Using Server Side Include Commands

• Using SSI Negatives
• Understanding How SSIs Work
  • Deciding Whether to Enable SSIs
  • Using the Options Directive
  • Using the AddType Command for SSIs
  • Using the srm.conf File
• Automatically Adding the Last Modification Date to Your Page
• Examining the Full Syntax of SSI Commands
• Using the SSI config Command
• Using the include Command
  • Analyzing the include Command
  • Using the virtual Command Argument
  • Using the file Command Argument
• Examining the flastmod Command
  • The Syntax of the SSI echo Command
  • The exec Command and CGI Scripts
• Looking At Security Issues with SSIs
• Learning Perl
  • Exercise 3.2. The Perl conditional statement if(){} else{}
• Summary
• Q&A

Chapter 4   Using Forms to Gather and Send Data

• Understanding HTML Form Tags
• Using the HTML Form Method Attribute
  • The Get and Post Methods
  • The Get Method
  • The Post Method
• Generating Your First Web Page On-the-Fly
  • Comparing CGI Web Pages to HTML Files
  • Analyzing first.cgi
  • Sending Variables in Your CGI Program
• Using the HTML Input Tag
  • Sending Data to Your CGI Program with the Text Field
  • Using the Submit Button to Send Data to Your CGI Program
• Making Your Text-Entry Form Fast and Professional Looking
• NPH-CGI Scripts
  • NPH-CGI Scripts Are Faster
  • URI-Encoded Data Ends Up in the Location Window
• Seeing What Happens to the Data Entered on Your Form
  • Name/Value Pairs
  • Path Information
• Using URI Encoding
  • Reserved Characters
  • The Encoding Steps
• Learning Perl
  • The Perl for Statement
  • The Perl foreach Statement
• Summary
• Q&A

Chapter 5   Decoding Data Sent to Your CGI Program

• Using the Post Method
• Using Radio Buttons in Your Web Page Forms and Scripts
  • The HTML Radio Button Format
  • The Name Attribute
  • The Value Attribute
  • The Checked Attribute
  • Radio Button Rules
• Reading and Decoding Data in Your CGI Program
  • Using the ReadParse Function
  • Creating Name/Value Pairs from the Query String
  • Decoding the Name/Value Pairs
  • Using the Post Method
  • Using the Perl read Function
  • Including Other Files and Functions in Your CGI Programs
  • Using the Data Passed with Radio Buttons
  • Using Perl's If Elsif Block
  • Using the HTML Checkbox
• Using a Database with Your CGI Program
• Using Pull-Down Menus in Your Web Page Forms and Scripts
  • Using the HTML Form Select Tag
  • Using the Option Field
• Using File Data in Your CGI Program
  • Opening a File
  • Reading Formatted Data
  • Using Formatted File Data
  • Using Data to Make Your CGI Programming Easier
• Learning Perl
  • Exercise 5.2. Using ARGV
  • Printing with Perl
• Summary
• Q&A

Chapter 6   Using Environment Variables in Your Programs

• Understanding Environment Variables
  • Program Scope
  • The Path Environment Variable
• Printing Your Environment Variables
• Sending Environment Variables to Your E-Mail Address
  • Perl Subroutines
  • The Unescape Subroutine
  • The cgi_encode Subroutine
  • The Main Mail Program
• Using the Two Types of Environment Variables
  • Environment Variables Based on the Server
  • Environment Variables Based on the Request Headers
• Finding Out Who Is Calling at YourWeb Page
• Getting the Username of Your Web Site Visitor
• Using the Cookie
• Returning the Cookie
• Learning Perl
  • Exercise 6.1. Using files with Perl
  • Understanding the Filename and Pathname
  • Understanding the Filehandle
  • Opening and Closing the File
  • Exercise 6.2. Using filehandles
  • Using Perl's Special Variables
• Summary
• Q&A

Chapter 7   Building an Online Catalog

• Using Forms, Headers, and Status Codes
• Registering Your Customer
• Setting Up Password Protection
  • Using the Password File
  • Using the Authentication Scheme
• Dealing with Multiple Forms
• Learning Perl
  • Perl's write Statement
  • The format Statement
  • Field Formatting
• Summary
• Q&A

Chapter 8   Using Existing CGI Libraries

• Using the cgi-lib.pl Library
  • Determining the Requesting Method
  • Decoding Incoming CGI Data
  • Printing the Magic HTTP Content Header
  • Printing the Variables Passed to Your CGI Program
  • Printing the Variables Passed to Your CGI Program in a Compact Format
• Using CGI.pm for Creating and Reading Web Forms
  • Installing CGI.pm
  • Reading Input Data
  • Saving Your Incoming Data
  • Saving the Current State of a Form
  • Creating the HTTP Headers
  • Creating an HTML Header
  • Ending an HTML Document
  • Creating Forms
  • Creating a Submit Button
  • Creating a Reset Button
  • Creating a Defaults Button
  • Creating a Hidden Field
  • Creating a Clickable Image Button
  • Controlling HTML Autoescaping
• Using the CGI Library for C Programmers: cgic
  • Writing a cgic Application
    
  • Using String Functions
  • Using Numeric Functions
  • Using Header Output Functions
  • A cgic Variable Reference
• Summary
• Q&A

Chapter 9   Using Imagemaps on Your Web Page

• Defining an Imagemap
• Sending the x,y Coordinates of a Mouse Click to the Server
  • Using the Ismap Attribute and the Img Tag
  • Using the Ismap Attribute with <INPUT TYPE=IMAGE>
• Creating the Link to the Imagemap Program
• Using the imagemap.c Program
• Using the Mapfile
  • Looking At the Syntax of the Imagemap File
  • Deciding Where to Store the Imagemap File
  • Increasing the Efficiency of Imagemap Processing
  • Using the Default URI
  • Ordering Your Mapfile Entries
• Using Client-Side Imagemaps
  • The Usemap Attribute
  • The HTML Map Tag
  • The Area Tag and Its Attributes
• Summary
• Q&A

Chapter 10   Keeping Track of Your Web Page Visitors

• Defining an Access Counter
• Using the Existing Access Log File
• Using page-stats.pl to Build Log Statistics
• Getting Access Counts for Your Entire Server from wusage 3.2
  • Configuring wusage
  • Charting Access by Domain
  • Running wusage
  • Purging the access_log File (How and Why)
• Examining Access Counter Graphics and Textual Basics
• Working with DBM Files
  • Locking a File
  • Creating Your Own File Lock
  • Using the flock() Command
• Excluding Unwanted Domains from Your Counts
• Printing the Counter
• Turning Your Counter into an Inline Image
  • Generating Counters from a Bitmap
  • Using the WWW Homepage Access Counter
  • Using the gd 1.2 Library to Generate Counter Images On-the-Fly
  • Using the gd 1.2 Library to Produce Images On-the-Fly
  • Global Types
  • Create, Destroy, and File Functions
  • Drawing Functions
  • Query Functions
  • Font and Text-Handling Functions
  • Color-Handling Functions
  • Copying and Resizing Functions
• Summary
• Q&A

Chapter 11   Using Internet Mail with Your Web Page

• Looking At Existing Mail Programs
  • The UNIX Mail Program
  • The UNIX sendmail Program
• Using Existing CGI E-Mail Programs
  • The WWW Mail Gateway Program
  • Using a Multilingual E-Mail Tool
• Building Your Own E-Mail Tool
  • Making Your Own E-Mail Form
  • Sending the Blank Form
  • Restricting Who Mail Can Be Sent To
• Implementing E-Mail Security
• Defining a Regular Expression
  • Positioning Your Regular Expression Match
  • Specifying the Number of Times a Pattern Must Occur
  • Using Regular Expression Special Characters
• Summary
• Q&A

Chapter 12   Guarding Your Server Against Unwanted Guests

• Protecting Your CGI Program from User Input
• Protecting Your Directories with Access-Control Files
  • The Directory Directive
  • The AllowOverride Directive
  • The Options Directive
  • The Limit Directive
  • The allow from Directive
  • The deny from Directive
  • The order Directive
  • The require Directive
• Setting Up Password Protection
  • The htpasswd Command
  • The Groupname File
• Using the Authorization Directives
  • The AuthType Directive
  • The AuthName Directive
  • The AuthUserFile Directive
  • The AuthGroupFile Directive
• Examining Security Odds and Ends
  • The emacs Files
  • The Path Variable
  • The Perl Taint Mode
• Cleaning Up Cookie Crumbs
• Summary
• Q&A

Chapter 13   Debugging CGI Programs

• Determining Which Program Has a Problem
• Determining Whether the Program Is Being Executed
• Checking the Program's Syntax
  • Checking Syntax at the Command Line
  • Interpreting Perl Error Messages
  • Looking At the Causes of Common Syntax Errors
• Viewing HTML Sources of Output
  • Using MIME Headers
  • Examining Problems in the HTML Output
• Viewing the CGI Program's Environment
  • Displaying the Raw Environment
  • Displaying Name/Value Pairs
• Debugging at the Command Line
  • Testing without the HTTP Server
  • Simulating a Get Request
  • Using Perl's Debug Mode
• Reading the Server Error Log
• Debugging with the Print Command
• Looking At Useful Code for Debugging
  • Show Environment
  • Show Get Values
  • Show Post Values
  • Display Debugging Data
• A Final Word about Debugging
• Summary
• Q&A

Chapter 14   Tips, Tricks, and Future Directions

• Making Browser-Sensitive Pages
• Simplifying Perl Code
• Looking At the Future of Perl
• Examining Python: A New Language for CGI
  • Comparing Python and Perl
  • Understanding the Python Language
  • Implementing Python
• Examining Java and JavaScript: Bringing Life to HTML
  • Understanding How Java Works
  • Understanding How a Java Program Is Executed
  • Looking At the Java Language
  • Implementing Java in Your System
  • Looking At JavaScript: Scripting for the Web
• Finding Useful Internet Sites for CGI Programmers
  • CGI Information
  • Perl Information
  • Specific Product Information
• Summary
• Q&A

Appendix A   MIME Types and File Extensions

Appendix B   HTML Forms

• Form Attributes
  • Action
  • Enctype
  • Method
  • Script
• Input Fields
  • Checkbox Fields
  • File Attachments
  • Hidden Fields
  • Image Fields
  • Password Fields
  • Radio Buttons
  • Range Fields
  • Reset Buttons
  • Scribble on Image Fields
  • Single-Line Text Fields
  • Submit Buttons
• Permitted Attributes for the Input Element
  • Accept
  • Align
  • Checked
  • Class
  • Disabled
  • Error
  • ID
  • Lang
  • Max
  • Maxlength
  • MD
  • Min
  • Name
  • Size
  • SRC (Source)
  • Type
  • Value
• Textarea
  • Cols
  • Rows
• Select Elements
  • Height
  • Multiple
  • SRC (Source)
  • Units
  • Width
• The Option Element

Appendix C   Status Codes and Reason Phrases

Appendix D   The ncSA imagemap.c Program

Appendix E   The Perl Quick Reference Manual

• Perl Operators and Their Precedence
• Perl Operators and Their Meanings
• Special Variables
• Perl Commands
• Miscellaneous Perl Rules
• GNU License Information