1. Desperately Seeking…
a lightweight Perl web framework
Peter Edwards
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Desperately seeking... a lightweight Perl web framework 12/22/12

2. Introduction
 Peter Edwards ~ background
Subject
 Explain about the processes and decision
making involved in assessing, selecting
and using a Perl web framework
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Desperately seeking... a lightweight Perl web framework
12/22/12

3. Aims
 Learn what frameworks are out there
 Technical considerations
 Business tools for decision-making
 Audience: What is your background and
interest?
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Desperately seeking... a lightweight Perl web framework
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4. Topics
 Define the problem
 Example requirements
 Attributes of frameworks
 Business decision making tools
 Architecture
 Application components
 Perl application frameworks
 Roll your own
 Summary
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Desperately seeking... a lightweight Perl web framework
12/22/12

5. Define the Problem
 Why do you need a web app?
 What functionality / how complex?
no. screens, other features, e.g. search engine, integration to other
apps/components/company infrastructure, server platform
 Business setting
Project length, size; Developer expertise, skill sets; Integration to
network, database type, existing frameworks e.g. ADS
authentication; Capacity plan - no. of users and required
performance
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Desperately seeking... a lightweight Perl web framework
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6. Example
http://merlinfootball.com
 Components
Flash front end, sending XML transactions to
Perl back end
Perl XHTML admin system
 Elements
Huge volume of users and transactions
Streaming video
Picture upload and approval to gallery
FAQ submission, approval and editing into FAQ
list
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Desperately seeking... a lightweight Perl web framework
12/22/12

7. Attributes of Frameworks
 Size -> complexity
 Learning curve
 Vertical vs. horizontal
 Functionality, flexibility
 Monotheistic/"One True Way" vs. agnostic
 Increased power, reduced performance
 Cost of testing new code = 50% of time
 By extension DRY KISS
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Desperately seeking... a lightweight Perl web framework
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8. Business Decision Making Tools
The point of business
Increased shareholder value - cash
William of Occam, 14th century logician and Franciscan friar
entia non sunt multiplicanda praeter necessitatem
entities should not be multiplied beyond necessity
"All things being equal, the simplest solution tends to be the best one.“
It often happens that the best explanation is much more complicated than the
simplest possible explanation because it requires fewer assumptions.
Pareto Principle, by Joseph M. Juran named after Vilfredo Pareto, Italian
economist
"for many phenomena, 80% of the consequences stem from 20% of the
causes“
-- en.wikipedia.org
Cost Benefit Analysis
Estimate days for development
Estimate hidden costs and benefits e.g. of more stable framework
Cost comparison -> decision
Perfection vs. pragmatism
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Desperately seeking... a lightweight Perl web framework
12/22/12

9. Architecture I
 Web Protocol
HTTP request/response
URI, REST, URL parameters
http://server.com/client/view/FRED?view=xml&tabs=al
Web 2.0, AJAX
 Web Server
Apache, IIS, lighttpd
CGI/mod_perl, FastCGI
 Controller Processing
Apache registry style stacked phase handlers
MVC Model View Controller
Single entry point vs. separate CGI
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Desperately seeking... a lightweight Perl web framework
12/22/12

10. Architecture II
 Session
CGI::Session
Apache::Session
Catalyst::Plugin::Session -> Cache::FastMMap
 Security
Authentication
Group permission roles
HTML field and SQL field encoding
 Database layer
Direct DBI
Simple Class::DBI
ORM Object Relational Mapper DBIx::Class Rose::DB
Performance considerations - DBI 10-100x faster
Data object attributes - data dictionary - screen dictionary
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Desperately seeking... a lightweight Perl web framework
12/22/12

11. Architecture III
 Templates
Template::Toolkit (TT2)
variable merge, not too complex,
encourages using Perl in app modules
HTML::Mason – inline code
Personal preference; understandable by Web designers
XHTML, accessibility, internationalisation
Locale::Maketext
Form handling, CRUD from db object, validation
Data::FormValidator
Rich components http://script.aculo.us/ http://
dojotoolkit.org/
 Testing
module unit test, business data object tests,
Javascript/browser compatability checks
Test::More Test::WWW::Mechanize
Test::WWW::Selenium
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Desperately seeking... a lightweight Perl web framework
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12. Application Components
Pre-built components
save time in short term on testing; may
cost more long term; integration costs
PHP::Session
Language Repository Template Component
Perl CPAN TT2 Bricolage
PHP PEAR Smarty CMSMS
Python Built-in Clearsilver Trac
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Desperately seeking... a lightweight Perl web framework
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13. Perl Application Frameworks
 CGI::Application + CGI::Session lightweight, easy to use, reliable, full
control, open
Watch out for CGI::Builder, based on CGI::App but used to have
Makefile.PL that downloaded and eval'd code, also bizarre "Perlish" coding
style
; use 5.006_001
; use Carp
; $Carp::Internal{+__PACKAGE__}++
; $Carp::Internal{__PACKAGE__.'::_'}++ ; use IO::Util
 CGI::Framework
fixed - glue between HTML::Template, CGI::Session, CGI,
Locale::Maketext last release 11-Oct-2005
 Jifty one true way: database mapper, template, web services, AJAX toolkit,
handlers for FastCGI continuations, form-based dispatch "Jifty is the only
web application framework that comes with a pony“
 Gantry + Bigtop Apache/mod_perl, MVC Bigtop - web application data
language processor, app generator
 OpenInteract + SPOPS Complex, slow, powerful, CMS-oriented
permissions last release 18-Mar-2005
 Catalyst
agnostic, MVC, complex, magic, powerful, slow (third time in NEXT/C3
OO extension), well tested Works well with DBIx::Class and TT2; can also
use Class:DBI, HTML::Mason Many plugins for auth, XML etc.
 Maypole (ancestor of Catalyst) similar approach Class::DBI, TT2
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Desperately seeking... a lightweight Perl web framework
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14. Roll Your Own
 "Not invented here" syndrome, AKA submitting
a module to CPAN with "Lite" or "Plus" in the
name.
 Can base on CGI::Application + CGI::Session
 Or write one yourself. Easier than you'd think.
Here's one written in a week, not pretty but
delivered a project delivered fast and on time:
http://perl.dragonstaff.co.uk/app.zip
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Desperately seeking... a lightweight Perl web framework
12/22/12

15. Summary
Processes and decision making
 requirements
 business context
 CBA decision basis
 technical considerations, architecture,
constraints and features
 application components
 Perl application frameworks
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Desperately seeking... a lightweight Perl web framework
12/22/12

16. Where to Get More Information
CPAN http://search.cpan.org
Books
 Any Questions
These slides are at
http://perl.dragonstaff.co.uk/
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Desperately seeking... a lightweight Perl web framework
12/22/12