How to create a simple Web application with Web::App Template::Toolkit and Class::DBI

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How to create a simple Web application with
WebApp TemplateToolkit and ClassDBI
Leonard Miller June 17, 2008
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Who is this talk for?
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Who is this talk for?

• Need to write web applications

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Who is this talk for?

• Need to write web applications
• Dont want/cannot have a heavy framework

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Who is this talk for?

• Need to write web applications
• Dont want/cannot have a heavy framework
• Experienced Programmers.

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Who is this talk for?

• Need to write web applications
• Dont want/cannot have a heavy framework
• Experienced Programmers.
• Know about CPAN, how to learn from CPANs
  documentation.

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Who is this talk for?

• Need to write web applications
• Dont want/cannot have a heavy framework
• Experienced Programmers.
• Know about CPAN, how to learn from CPANs
  documentation.
• Newer programmers that could use a new/better way
  to organize their code.

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Why these three Modules?

• Separate out the code to MVC Pieces
• Each can be used/tested alone
• The modules themselves are easy to use and
  understand

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Why not Catalyst?

• mod_perl/fastcgi You dont always have the
  access on the machine to get Catalyst to work.
• CGIApplication is a lite framework, and as
  such is much smaller.
• Not as big and scary.
• Trivial to install in a local /lib dir

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What is MVC

• MVC stands for Model-View-Controller

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What is MVC

• MVC breaks the work into three parts

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What is MVC

• MVC breaks the work into three parts
• Model - Short for database model. ClassDBI does
  all the database work inserts/queries.

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What is MVC

• MVC breaks the work into three parts
• Model - Short for database model. ClassDBI does
  all the database work inserts/queries.
• View - TemplateToolkit does all the view/html
  work.

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What is MVC

• MVC breaks the work into three parts
• Model - Short for database model. ClassDBI does
  all the database work inserts/queries.
• View - TemplateToolkit does all the view/html
  work.
• Controller - CGIApplication holds all the logic
  to glue the Model and the View together.

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What is MVC

• Who has seen code like this
• use DBI
• my sql "select from users"
• my dbh DBI-gtconnect( ds, un, pw )
• my sth dbh-gtprepare(sql)
• sth-gtexecute()
• print "Content-type text/html\r\n\r\n"
• while (my h sth-gtfetchrow_hashref())
• print Name is".h-gt'first_name'."ltbrgt\n"

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What is MVC

• Who has seen code like this
• my q new CGI
• if (q-gt param('first_name' eq '')
• print input_form()
• else
• my sql "insert into users ..."
• my sth dbh-gtprepare(sql)
• sth-gtexecute()
• print submission_form()

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What is MVC

• Any questions regarding what MVC is?

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CGIApplication

• A sample program
• Helloworld.cgi lt- config info
• HelloWorldCgiApp.pm lt- controller
• Html files lt- View
• header.html
• body.html
• footer.html
• MyDatabase.pm lt- Model

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CGIApplication

• helloworld.cgi
• use HelloWorldCgiApp
• my helloworld HelloWorldCgiApp-gtnew()
• helloworld-gtrun()

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CGIApplication

• helloworld.cgi (with config info)
• use HelloWorldCgiApp
• my helloworld HelloWorldCgiApp-gtnew
• (
• PARAMS gt
• tt_config gt
• INCLUDE_PATH gt ".",
• PRE_PROCESS gt 'header.html',
• POST_PROCESS gt 'footer.html',
• ,
• hw_string gt "hi there big earth!",
• ,
• )
• helloworld-gtrun()

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CGIApplication

• HelloWorldCgiApp (continued)
• package HelloWorldCgiApp
• use base 'CGIApplication'
• use Template
• sub setup
• my self shift
• self-gtrun_modes( 'mode1' gt 'start,
• 'mode2' gt 'sec_page'
• )
• self-gtstart_mode('mode1')

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CGIApplication

• HelloWorldCgiApp (continued)
• package HelloWorldCgiApp
• use base 'CGIApplication'
• use Template
• sub setup
• my self shift
• self-gtrun_modes( 'mode1' gt 'start,
• 'mode2' gt 'sec_page'
• )
• self-gtstart_mode('mode1')

q -gt param (rm)
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CGIApplication

• HelloWorldCgiApp (continued)
• sub start
• my self shift
• my tt_config self-gtparam(tt_config)
• my tt Template-gtnew( tt_config )
• tt-gtprocess('body.html',
• hwstr gt 'hi big planet!!!',
• ,
• \html)
• return html

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CGIApplication

• HelloWorldCgiApp (continued)
• sub cgiapp_prerun
• my (self, runmode) _at__
• my q self-gtquery

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ClassDBI

• The mysql table
• CREATE TABLE users (
• user_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
• first_name varchar(75) NOT NULL,
• last_name varchar(75) NOT NULL,
• country_code CHAR(2) NULL
• )

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ClassDBI

• MyDatabase.pm
• package MyDatabase
• use base 'ClassDBI'
• MyDatabase-gtconnection('dbimysqldb',user,pw')
  
• MyDatabase -gt table('users')
• MyDatabase -gt columns( All gt qw/user_id
• first_name last_name country_code / )
• MyDatabase -gt columns( Primary gt user_id )

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ClassDBI

• Using the ClassDBI Module
• HelloWorldCgiApp.pm
• use MyDatabase
• my _at_users MyDatabase -gt retrieve_all
• tt-gtprocess('body.html',
• users gt _at_users ,
• ,
• \html)

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ClassDBI

• Using the Module
• use MyDatabase
• my _at_users MyDatabase -gt retrieve_all
• my user MyDatabase -gt retrieve( 1 )
• tt-gtprocess('body.html',
• users gt _at_users ,
• user gt user,
• ,
• \html)

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ClassDBI

• Using the Module inserts
• use MyDatabase
• my user MyDatabase -gt insert(
• first_name gt Randall,
• last_name gt Schwartz,
• country_code gt US,
• )

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TemplateToolkit

• Why use TemplateToolkit?
• Common look and feel templates.
• Easy to change for those people who are better at
  design than we are.
• What type of data is It good for?
• arrays
• hashes
• scalars

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TemplateToolkit

• Any html file is a TT file!
• Simplest usage for a scalar
• lthtmlgt
• ltbodygt
• var_name
• lt/bodygt
• lt/htmlgt

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TemplateToolkit

• Usage for an Array where users is an array
• ltbodygt
• FOREACH item IN users
• item ltbr /gt
• END
• lt/bodygt

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TemplateToolkit

• Usage for an Array where users is a hash
• ltbodygt
• item.user_id item.first_name
  item.last_name item.country_code ltbr /gt
• lt/bodygt

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TemplateToolkit

• Usage for an Array where users is an array of
  hashes (like an array of rows from a database)
• ltbodygt
• FOREACH item IN users
• item.user_id item.first_name
• item.last_name item.country_codeltbr /gt
• END
• lt/bodygt

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TemplateToolkit

• Usage for an Array where users is an array of
  hashes (like an array of rows from a database)
• ltbodygt
• ltformgt
• ltinput typehidden namerm valuepage_2
• FOREACH item IN users
• ...
• END
• ltinput typesubmitgt
• lt/formgt
• lt/bodygt

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• Questions?

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• Thank you

Leonard Miller June 17, 2008