Intro to Dancer - OSCON 2011

Introduction to Dancer!A Sinatra-inspired web framework for Perl!!!Mark Allen!mrallen1@yahoo.com!http://byte-me.org!http://github.com/mrallen1!http://bitbucket.org/mrallen1!https://metacpan.org/author/MALLEN!

The Old Days!

The Old Dayscgi-lib.pl (1994-1998)! !

The Old DaysCGI.pm (1995-2011)! !

The Old Daysmod_perl (1996-2011)! !

The Old Days Matt’s Script Archive (1995-2011)! ! Use instead:!http://nms-cgi.sourceforge.net/! (Thanks London.pm)!!

The Old Daysuse CGI.pm;!!my $q = CGI->new();!my ($a, $b, $c) = $q->param();!!if ($a !~ /d+/) {! !print $q->header(-status => ‘400 Bad request’);! !print “<h1>Value of ‘a’ ($a) is not an integer</h1>”;! !exit 0;!}!# yada, yada!

The Old Days.htaccess Hack!!!RewriteEngine On!RewriteBase /abc!!RewriteRule ^(.*)/(.*)/(.*)$ !abc.pl?a=$1;b=$2;c=$3!!

The Old Days.htaccess Hack!!# Use Web 2.0 style URLs, but keep CGI interface!RewriteEngine On!RewriteBase /abc!!RewriteRule ^(.*)/(.*)/(.*)$ !abc.pl?a=$1;b=$2;c=$3!!

The Old Daysh"p://ﬂic.kr/p/5TWTR4

Move over bacon, now there’ssomething leaner.! !

Move over baconPerl 5 Renaissance:!•  Moose!•  DBIx::Class!•  Plack!•  Tons of great new stuff in core perl 5.10+! !

Move over bacon Do you ﬁnd Catalyst too !heavyweight or intimidating?! !

Move over bacon !Me too!! ! !

Move over baconEnter Dancer! !

Move over baconOther Sinatra-inspiredframeworks:!•  Mojo (Perl – TMTOWTDI)!•  Flask (Python)!•  Fitzgerald (PHP)!•  Express (Node.js)!!

Move over baconDancer is:!•  Easy to learn!•  Expressive!•  Efﬁcient!

Dancer is ...!! Easy to learn!

Easy to learnBasic Dancer concepts:!•  One (or more) HTTP verb(s)!•  A route!•  A handler!

Easy to learnuse Dancer;!!get / => sub {! return Hello World!n’;!};!!start;!

Easy to learn

Easy to learnget / => sub {! my $db = connect_db();! my $sql = select id, title, text from entriesorder by id desc’;! my $sth = $db->prepare($sql) or die $db->errstr;! $sth->execute or die $sth->errstr;! template show_entries.tt, {! msg => get_flash(),! add_entry_url => uri_for(/add),! entries => $sth->fetchall_hashref(id),! };!};!

Easy to learnshow_entries.tt!!<ul class=entries>! <% IF entries.size %>! <% FOREACH id IN entries.keys.nsort %>! <li><h2><% entries.$id.title %></h2>! <% entries.$id.text %>! <% END %>! <% ELSE %>! <li><em>Unbelievable. No entries here sofar</em>! <% END %>!</ul>! !

Easy to learnget / => sub {! my $db = connect_db();! my $sql = select id, title, text from entriesorder by id desc’;! my $sth = $db->prepare($sql) or die $db->errstr;! $sth->execute or die $sth->errstr;! template show_entries.tt, {! msg => get_flash(),! add_entry_url => uri_for(/add),! entries => $sth->fetchall_hashref(id),! };!};!

Easy to learnshow_entries.tt!!<ul class=entries>! <% IF entries.size %>! <% FOREACH id IN entries.keys.nsort %>! <li><h2><% entries.$id.title %></h2>! <% entries.$id.text %>! <% END %>! <% ELSE %>! <li><em>Unbelievable. No entries here sofar</em>! <% END %>!</ul>! !

Easy to learnshow_entries.tt!!<ul class=entries> <!– CSS class -->! <% IF entries.size %>! <% FOREACH id IN entries.keys.nsort %>! <li><h2><% entries.$id.title %></h2>! <% entries.$id.text %>! <% END %>! <% ELSE %>! <li><em>Unbelievable. No entries here sofar</em>! <% END %>!</ul>! !

Easy to learnDirectory structure ! dancr/! ├── dancr.pl! ├── public! │ └── css! │ └── style.css! └── views! ├── layouts! │ └── main.tt! ├── login.tt! └── show_entries.tt!

Dancer is...!! Expressive!

Expressivepost /add => sub {! if ( not session(logged_in) ) {! return send_error("Not logged in", 401);! }!! my $db = connect_db();! my $sql = insert into entries (title, text)values (?, ?)’;! my $sth = $db->prepare($sql)  or die $db->errstr;! $sth->execute(params->{title},   params->{text})   or die $sth->errstr;!! set_flash(New entry posted!);! redirect /’;!};!

ExpressiveLittle Bobby Tables!h"p://xkcd.com/327/

Expressivepost /add => sub {! if ( not session(logged_in) ) {! return send_error("Not logged in", 401);! }! # http://bobby-tables.com! my $db = connect_db();! my $sql = insert into entries (title, text)values (?, ?)’;! my $sth = $db->prepare($sql)  or die $db->errstr;! $sth->execute(params->{title},   params->{text})   or die $sth->errstr;!! set_flash(New entry posted!);! redirect /’;!};!

Expressive

ExpressiveConﬁguration !•  Session Engine!•  Template Engine!•  Logging !•  Plugins!

ExpressiveConﬁguration Examples!  set session => Simple; set template =>template_toolkit; set logger => console; set log => debug; set show_errors => 1; !

ExpressiveConﬁguration  Use any non-reserved key/value pair.  set username => admin; set password => password;!!

ExpressiveRoutes with regex!! get qr{A/(?<code>[A-Za-z0-9]+)Z} => sub {! my $decode = decode_base36(  uc captures->{code}! );! ...;!};!

ExpressiveRoutes with regex!!use v5.10; get qr{A/(?<code>[A-Za-z0-9]+)Z} => sub {! my $decode = decode_base36(  uc captures->{code}! );! ...;!};!

ExpressiveRoutes with named params!!get /:code/stats => sub {! my $decode = decode_base36(  uc params->{code}  );! ...;!};!

ExpressiveRoutes with named params!!get qr{^/(.+)/stats$} => sub {  params(‘code’) = $1;  # input sanity goes here  ...; };!

Expressiveuse CGI.pm;!!my $q = CGI->new();!my ($a, $b, $c) = $q->param();!!if ($a !~ /d+/) {! !print $q->header(-status => ‘400 Bad request’);! !print “<h1>Value of ‘a’ ($a) is not an integer</h1>”;! !exit 0;!}!# yada, yada!

Expressive!!!!use v5.10; use Dancer;  !get qr{/(?<a>d+)/(?<b>.+)/(?<c>.+)} => sub {! # Route will only match if a is an integer!  # No more sanitation/validation necessary  ...; };!!

Dancer is...  ! Efﬁcient!

Efficientany [get, post] => /login => sub {! my $err;! if ( request->is_post ) {! if ( params->{username} ne setting(username) ) {! $err = "Invalid username”;! }! elsif ( params->{password} ne setting(password) ) {! $err = "Invalid password”;! }! else {! session logged_in => true;! set_flash(You are logged in.);! redirect /’;! }! }! template login.tt, {! err => $err,! };!};!

EfficientHook Before / After!•  De/Serialization!•  Rendering!•  Template!•  Errors!

EfficientForward!!get /demo/foo/:bar => sub {! my $bar = param->{bar};! # magically use demo DB! ...;! return forward "/foo/$bar";!};!!

EfficientPreﬁx!!prefix /user; # begins scope!!get /view/:id => sub { ...; };!post /add => sub { ...; };!any [get, post] => /edit/:id => sub { ...; };!!prefix undef; # ends scope!!get /view/:id => sub { ...; };!

EfficientDancer Plugins add keywords !•  Auto-create RSS feeds!•  Integrate Twitter for authN!•  DBIx::Class!•  DWIM CRUD apps!•  ...and more!

Dancer is...!! Awesome!!

AwesomeSource code:!hg clone https://bitbucket.org/mrallen1/dancr!!See also:!https://metacpan.org/module/Dancer!!Install:!curl -L http://cpanmin.us | perl - Dancer YAML Template!!

AwesomeThank You!! !

Intro to Dancer - OSCON 2011

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Intro to Dancer - OSCON 2011 Presentation Transcript