1. Plack
Superglue for Perl Web Frameworks
Tatsuhiko Miyagawa
OSDC. 2010

2. •
• Six Apart
• 177 CPAN modules (id:MIYAGAWA)
• @miyagawa
• http://bulknews.typepad.com/

4. Web Frameworks
(in Perl)

6. Sharing, Stealing
and Importing

8. Web Frameworks
in Perl

9. Many ways to write
Perl web applications

10. Maypole Mason Mojo Sledge Catalyst Spoon
PageKit AxKit Egg Gantry Continuity Solstice
Mojolicious Tripletail Konstrukt Reaction Jifty
Cyclone3 WebGUI OpenInteract Squatting
Dancer CGI::Application Nanoa Ark Angelos
Noe Schenker Tatsumaki Amon
Apache2::WebApp Web::Simple Apache2::REST
SweetPea Hydrant Titanium

11. Some ways to run
Perl web applications

12. CGI, FastCGI
& mod_perl

13. CGI.pm

14. Runs “fine” on:
CGI, FastCGI, mod_perl (1 & 2)
Standalone (with HTTP::Server::Simple)

15. CGI.pm = LCD
Perl core module

16. 8803 lines of code
First ver. in Nov.1995

17. :-(

18. CGI.PM
MUST
DIE!

19. (just kidding)

20. Catalyst
The most popular perl web framework as of today

21. Catalyst::Engine::*
Server abstractions.
Apache, FastCGI, Standalone and Prefork
No CGI.pm

22. CGI.pm
Jifty, CGI::Application, Spoon
mod_perl centric
Mason, Sledge, PageKit, WebGUI
Adapters
Catalyst, Maypole, Squatting

25. Can we share?

26. ?

27. HTTP::Engine
Yappo, tokuhirom and nothingmuch etc.

28. :-)
Ported Catalyst engine code
and made it sharable

29. :-(
Monolithic code base
No separation of interface & impl.

30. 2009

32. Steal great idea
from Python/Ruby

33. Import stuff
proven popular
from Python/Ruby

35. PROVEN POPULAR!

36. Popular and successful
in Python and Ruby

37. WSGI (Python)
Rack (Ruby)

38. WSGI (PEP-333)

40. WSGI
• Django • mod_wsgi
• Bottle • Paste
• CherryPy • gunicorn
• Tornado • uWSGI
• Pylons • wsgiref
• Flask • Google AppEngine

41. Django Bottle Flask Tornado
WSGI middleware
WSGI
wsgi handlers
Apache lighttpd nginx mod_wsgi GAE

42. Rack

44. Rack
• Rails • Unicorn
• Merb • Thin
• Sinatra • Mongrel
• Camping • Rainbows!
• Ramaze • Phusion Passenger
• etc. • Heroku

45. Rails Merb Sinatra Ramaze
Rack middleware
Rack
Rack handlers
Apache lighttpd Thin Unicorn Mongrel

46. PSGI
Perl Web Server Gateway Interface

47. Interface

49. # WSGI
def hello(environ, start_response):
start_response(“200 OK”, [
(‘Content-Type’, ‘text/plain’)
])
return [“Hello World”]

50. # Rack
class Hello
def call(env)
return [
200,
{ “Content-Type” => ”text/plain” },
[“Hello World”]
]
end
end

51. # PSGI
my $app = sub {
my $env = shift;
return [
200,
[ ‘Content-Type’, ‘text/plain’ ],
[ ‘Hello World’ ],
];
};

52. PSGI application
code reference
$app = sub {...};

53. my $app = sub {
my $env = shift;
return [ $status, $header, $body ];
};

54. environment hash
$env: CGI-like env variables
+ psgi.input, psgi.errors etc.

55. my $app = sub {
my $env = shift;
return [ $status, $header, $body ];
};

56. Response
array ref with three elements
status code, headers (array ref)
and body (IO-like or array ref)

57. my $app = sub {
my $env = shift;
return [ $status, $header, $body ];
};

58. $body
IO::Handle-like
getline() and close()

59. IO::Handle::Util
Easily turns perl code ref into a IO::Handle

60. Streaming interface

61. my $app = sub {
my $env = shift;
return sub {
my $respond = shift;
# You could do some event loop
# to delay response (e.g. Comet)
$respond->([ $status, $header, $body ]);
};
};

62. my $app = sub {
my $env = shift;
return sub {
my $respond = shift;
my $w = $respond->([ $status, $header ]);
$w->write($body);
$w->write($body);
...
$w->close;
};
};

63. Streaming Interface
Originally designed for non-blocking servers
Now available for most servers incl. CGI, Apache

64. Catalyst CGI::App Jifty Tatsumaki
Plack::Middleware
PSGI
Plack::Handler::* (CGI, FCGI, Apache)
Apache lighttpd HTTP::Server::PSGI mod_psgi Perlbal

65. PSGI adaptation

66. Maypole Mason Mojo Sledge Catalyst Spoon PageKit
AxKit Egg Gantry Continuity Solstice Mojolicious
Tripletail Konstrukt Reaction Jifty Cyclone3 WebGUI
OpenInteract Squatting Dancer CGI::Application
Nanoa Ark Angelos Noe Schenker Tatsumaki Amon
Apache2::WebApp Web::Simple Apache2::REST
SweetPea Hydrant Titanium

67. Maypole Mason Mojo Sledge Catalyst Spoon PageKit
AxKit Egg Gantry Continuity Solstice Mojolicious
Tripletail Konstrukt Reaction Jifty Cyclone3 WebGUI
OpenInteract Squatting Dancer CGI::Application
Nanoa Ark Angelos Noe Schenker Tatsumaki Amon
Apache2::WebApp Web::Simple Apache2::REST
SweetPea Hydrant Titanium

68. Applications
Movable Type, WebGUI

69. # Catalyst
use MyApp;
MyApp->setup_engine(‘PSGI’);
my $app = sub { MyApp->run(@_) };
# $app is a PSGI app!

70. # Jifty
use MyPonyApp;
my $app = MyPonyApp->psgi_app;
# $app is a PSGI app!

71. # Dancer
use Dancer;
get ‘/’ => sub {
“Hello World”;
};
use Dancer::Config ‘setting’;
setting apphandler => ‘PSGI’;
my $app = sub {
my $r = Dancer::Request->new(shift);
Dancer->dance($r);
};
# $app is a PSGI app!

72. # Mojolicious::Lite
use Mojolicious::Lite;
get ‘/:name’ => sub {
my $self = shift;
$self->render_text(‘Hello!’);
};
shagadelic; # returns PSGI app

73. # Web::Simple
use Web::Simple ‘MyApp’;
package MyApp;
dispatch {
sub(GET) {
[ 200, [...], [ ‘Hello’ ] ];
}
};
my $app = MyApp->as_psgi;
# $app is a PSGI app!

74. Plack
“PSGI toolkit”

75. HTTP::Server::PSGI
Reference PSGI web server
bundled in Plack

76. Plack::Handler
Connects PSGI apps to Web servers
CGI, FastCGI, Apache, SCGI

77. Plackup
Runs PSGI app instantly from CLI
(inspired by rackup)

78. > plackup app.psgi

79. DEMO

80. Middleware

82. my $app = sub {
my $env = shift;
return [ $status, $header, $body ];
};
my $mw = sub {
my $env = shift;
# do something with $env
my $res = $app->($env);
# do something with $res;
return $res;
};

83. Middleware
Debug, Session, Logger, Runtime, Static, AccessLog,
ConditionalGET, ErrorDocument, StackTrace,
Auth::Basic, Auth::Digest, ReverseProxy, Refresh etc.
(Imported from Rack and Paste)

84. Plack::Middleware
reusable and extensible
Middleware framework
Plack::Builder DSL in .psgi

85. my $app = sub {
return [ $status, $header, $body ];
};
use Plack::Builder;
builder {
enable “Static”, root => “/htdocs”,
path => qr!^/static/!;
enable “Deflater”; # gzip/deflate
$app;
}

86. plackup compatible
plackup -e ‘enable “Foo”;’ app.psgi

87. DEMO

88. Plack::App::URLMap
Multiplex multiple apps
Integrated with Builder DSL
(Imported from Rack)

89. use CatApp;
use CGIApp;
my $c1 = sub { CatApp->run };
my $c2 = sub { CGIApp->run_psgi };
use Plack::Builder;
builder {
mount “/cat” => $c1;
mount “/cgi-app” => builder {
enable “StackTrace”;
$c2;
};
}

90. CGI::PSGI
Easy migration from CGI.pm

91. CGI::Emulate::PSGI
CGI::Compile
Easiest migration from CGI scripts (like Registry)

92. Plack::Request
like libapreq (Apache::Request)
wrapper APIs for middleware developers

93. Plack::Test
Unified interface to write tests
with Mock HTTP and Live HTTP

94. use Plack::Test;
use HTTP::Request::Common;
my $app = sub {
my $env = shift;
return [ $status, $header, $body ];
};
test_psgi app => $app, client => sub {
my $cb = shift;
my $req = GET “http://localhost/foo”;
my $res = $cb->($req);
# test $res;
};

95. use Plack::Test;
use HTTP::Request::Common;
$Plack::Test::Impl = “Server”;
my $app = sub {
my $env = shift;
return [ $status, $header, $body ];
};
test_psgi app => $app, client => sub {
my $cb = shift;
my $req = GET “http://localhost/foo”;
my $res = $cb->($req);
# test $res;
};

96. PSGI Web Servers

97. Starman
UNIX Preforking HTTP servers (like Unicorn.rb)
HTTP/1.1 chunk + keep-alives / Very Fast

98. Twiggy
Non-blocking web server (like Thin.rb)
based on AnyEvent framework

99. Corona
Coroutine for each connection based on Coro.pm

100. HTTP::Server::Simple::PSGI
Zero-deps other than HTTP::Server::Simple
Best for embedding PSGI applications

101. nginx embedded perl
http://github.com/yappo/nginx-psgi-patchs

102. mod_psgi
http://github.com/spiritloose/mod_psgi

103. evpsgi
http://github.com/sekimura/evpsgi

104. Perlbal plugin
http://github.com/miyagawa/Perlbal-Plugin-PSGI

105. uWSGI
http://projects.unbit.it/uwsgi/

106. Catalyst CGI::App Jifty Tatsumaki
Plack::Middleware
PSGI
Plack::Handler::* (CGI, FCGI, Apache)
Apache lighttpd HTTP::Server::PSGI mod_psgi Perlbal
Starman Twiggy uWSGI Corona evpsgi

107. Play with it

108. > cpanm Plack
> cpanm Task::Plack

109. Cloud?
(Heroku, GAE)

110. Sunaba
http://sunaba.plackperl.org/

112. Runs on ’s
Sandbox ( )

113. You can even try:
system(“rm -fr /”);
while (1) { }

114. • PSGI is an interface, Plack is the code.
• We have many (pretty fast) PSGI servers.
• We have adapters and tools for most web
frameworks.
• Use it!

115. • Sharing is important.
• Stealing is a good start.
• Importing something successful is great.

116. http://github.com/miyagawa/Plack
http://plackperl.org/
http://blog.plackperl.org/
irc://irc.perl.org/#plack

117. ?

118. :-)