Web Development in Perl

WEB DEVELOPMENT IN Perl Naveen Gupta nkrgupta@gmail.com

AGENDA

Introduction to Web Development & Perl

Perl Powered Sites/Application

Basic Web Programming in Perl

CGI Programming in Perl

Creating HTML Forms

mod_perl

Templating Systems in Perl

Web 2.0 Applications in Perl

Perl vs PHP - A Tale of 2 Languages

Introduction to Web Development

What is Web Dev?

– Development of websites, internet applications, e-commerce sites, social networks etc.

– Includes Web Designing, Content Development, client/server side coding, Web Server configuration

– Flexible Model, easy to adopt to, Barriers to entry very low

– Contributing Factors - Propagation of Open Source Technologies, WYSIWYG Tools, Internet Awareness

– Killer Apps – Google Docs, Flickr, WordPress, PhpBB, WikiMedia, YouTube and millions others

Dominant Technologies

C, C++, Pascal, Shell Script

ASP

JAVA, J2EE and related Frameworks

Perl with or without CGI

PHP

.NET – C#, VB.NET

Python

Ruby on Rails

ColdFusion

Introduction to Perl

Created by Larry Wall in 1987

Interpreted, Scripting Language

C - like syntax

Best of C, awk and sed

Best language for Text Manipulation/ Data Processing

Swiss Army knife for SysAdmins, Programmers

Supports modules, OO, DB interaction, pointers, regular expressions, multithreading, sockets, MVC frameworks

Highly Portable, well documented

Perl and the WEB

De facto language for CGI Programs

Made popular by Matt’s Script Archive

Easy to build and maintain

Wide acceptance of LAMP framework – Linux, Apache, MySQL, PHP/Perl/Python/Ruby

Great DB support via DBI set of Modules

Strength of Perl – CPAN, Comprehensive Perl Archive Network

Hands down winner with the advent of mod_perl, FastCGI, Catalyst, Moose etc.

How to get Perl?

- For *NIX Platforms – Included with almost every Linux, BSD, Solaris, OS X installation. Source can be can be downloaded from http://www.perl.org and compiled using “ gcc”. RPMs are also available.

- For Windows Platforms – Installation Binary distributed by http://www.activestate.com as ActivePerl. Yet, complete LAMP installations distributed by http:// www.apachefriends.org , http://www.apache.org , http://www.indigostar.com etc. are most popular. Complete listing can be found at http://www.perl.org/ports

Perl Powered Sites/Applications

My First Web Program in Perl

#!/usr/bin/perl print “Content-type:/text/html ”; print “Hello World!<br>”;

Adding a Bit of `Perl`

#!/usr/bin/perl print “Content-type:/text/html ”; my $time= localtime ( time ); print “Today is $time <br>”; foreach my $key ( sort keys %ENV){ print qq{$key = $ENV{$key} <br>}; }

Jazz it up with a little HTML

#!/usr/bin/perl print “Content-type:/text/html ”; print “<h1>Welcome to my First Perl Web page</h1>”; print “Perl is a great language!<br>”; print “It can create killer websites too!<br>”; print “Wanna see how?”;

Here Document

#!/usr/bin/perl print “Content-type:/text/html ”; print <<HTML; <h1>Welcome to my First Perl Web page</h1> Perl is a great language!<br> It can create killer websites too!<br> Wanna see how? HTML

Going Dynamic with CGI

#!/usr/bin/perl use CGI; use strict; my $cgi=new CGI; print $cgi->header(); print $cgi->start_html(-title=>’First CGI.pm program’, -meta=>{‘keywords’=>’perl cgi’, ‘ copyright’=>’WebOSS ‘07’}, -style=>{‘src’=>’style.css’}, -BGCOLOR=>’blue’); contd….

… contd Going Dynamic with CGI print $cgi->h1(“Welcome to a CGI APP!”); print “Your IP Address is : ”.$ENV{‘REMOTE_ADDR’}.“<br>”; print “You have been directed here from: $ENV{‘HTTP_REFERER’}” ; print $cgi->a({-href=>’http://search.cpan.org’, -target=>’_blank’}, “Go to CPAN!”); print $cgi->end_html;

The Power of mod_perl

“… mod_perl is more than CGI scripting on steroids. It is a whole new way to create dynamic content by utilizing the full power of the Apache web server to create stateful sessions, customized user authentication systems, smart proxies and much more. Yet, magically, your old CGI scripts will continue to work and work very fast indeed. With mod_perl you give up nothing and gain so much! …” – Lincoln Stein, Author – CGI.pm

- Perl Interpreter embedded in Apache

- Overcomes one-process-per-request limitation of CGI, 100x faster!

- Write Apache modules in Perl instead of C

- Hundreds of Modules available in CPAN

- Numerous Application Frameworks, Templating Systems

- Configure Apache’s httpd.conf via Perl

Perl Templating Systems

HTML::Mason

Template Toolkit

HTML::Template

SSI using mod_include or Apache::SSI module

Why use Templating System?

Consistency of Appearance

Reusability

Abstraction between logic and design

Division of Labour

Web 2.0 Apps in Perl

CGI::Ajax

Object Oriented module by Brian C. Thomas

Eliminates the need to write JS for AJAX Calls

Generates JS Functions from output by Perl subroutines

Can be implemented in large projects

HTML::TagCloud

Generates Tag Clouds, with different font sizes

CSS Based

Add method takes 3 arguments – a) Tag Name

b) URL to link to

c) Weight

WEB DEVELOPMENT IN Perl Perl vs PHP

APACHE INTEGRATION DOCUMENTATION API/ LIBRARY SUPPORT LEARNING CURVE PURPOSE/ UTILITY mod_php mod_perl, Fast CGI http:// www.php.net Perldoc, http:// perldoc. perl.org , CPAN PEAR and PECL, both from http://www.php.net 48606 active modules on CPAN and many others elsewhere Easier than Perl Easier than C, JAVA, .NET Made primarily for WEB. Can do CLI and other tasks. Multi-purpose, primarily for text pocessing, equally suited for sysadmin and web apps PHP Perl

WordPress, phpBB, Drupal, Coppermine, phpMyAdmin AWStats, Slash Code, BugZilla CMS / APPLICATIONS Yes, the main reason for its popularity Only with Modules like Mason, HTML::Template, Template::Toolkit etc. HTML EMBED PHP Perl