Plack basics for Perl websites - YAPC::EU 2011

Plack Basics

Leo Lapworth @ YAPC::EU 2011

Much content from Tatsuhiko Miyagawa’sYAPC::NA 2010 talk

What is Plack?

What is Plack?

“Superglue for Perl 5 Web Frameworks and Web

Servers”

How will that help me?

How will that help me?‣ Flexibility


‣ Middleware (plugins)



‣ Apps



‣ Apps

‣ Development



‣ Apps

‣ Development

‣ Testing



‣ Apps

‣ Development

‣ Testing

‣ Deployment



‣ Apps

‣ Development

‣ Testing

‣ Deployment

‣ World peace

History...

Hello World

#!/usr/bin/perluse strict;

print “Content-Type: text/plain\r\n\r\n”;print “Hello World”;

package HelloWorld;use strict;use Apache::RequestRec;use Apache::RequestIO;use Apache::Const -compile => qw(OK);

sub handler { my $r = shift;

$r->content_type(‘text/plain’); $r->print(“Hello World”);

return Apache::Const::OK;}

1;

use FCGI;

my $req = FCGI::Request();

while ($req->Accept >= 0) {

print “Content-Type: text/plain\r\n\r\n”; print “Hello World”;

}

package HelloWorld;use base qw(HTTP::Server::Simple::CGI);

sub handle_request { my($self, $cgi) = @_;

print “HTTP/1.0 200 OK\r\n”; print “Content-Type: text/plain\r\n\r\n”; print “Hello World”;}

1;

All similar but slightly different

Painful to supportall of them

There wasone common way to do all of this.

CGI.pm

#!/usr/bin/perluse CGI;

my $q = CGI->new;

print $q->header(‘text/plain’);print “Hello World”;

Works under...CGI

FastCGImod_perl

HTTP::Server::Simple::CGI

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

CGI.pm?

CGI.pm?meh

Frameworks to the rescue!

Catalyst Maypole Mason Mojo Sledge 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

Let’s look how they handled web servers.

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

CGI::Application

Apache IIS lighttpd

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

Jifty

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

Jifty Catalyst

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

Jifty Catalyst

Catalyst::Engine

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

Jifty Catalyst

Catalyst::Engine

nginx

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

Jifty Catalyst

Catalyst::Engine

nginxHTTP::Server::Simple

CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

JiftyMason Catalyst

Catalyst::Engine


CGI::Application

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

JiftyMason Catalyst

Mason::CGIHandlerCatalyst::Engine


Gross.

CGI.pmJifty, CGI::Application, Spoon

mod_perl centricMason, Sledge, PageKit, WebGUI

AdaptersCatalyst, Maypole, Squatting

That was 2008...

Gentleman thief &Double agent

Miyagawa

Acquired a great ideafrom Python/Ruby

WSGI (Python)Rack (Ruby)

WSGI (PEP-333)

WSGI Python Frameworks• Django

• Bottle

• CherryPy

• Tornado

• Pylons

• Flask

• mod_wsgi

• Paste

• gunicorn

• uWSGI

• wsgiref

• Google AppEngine

WSGI

WSGI middleware

Django Bottle Flask Tornado

Apache lighttpd nginx mod_wsgi

wsgi handlers

GAE

Rack Ruby Frameworks• Rails

• Merb

• Sinatra

• Camping

• Ramaze

• etc.

• Unicorn

• Thin

• Mongrel

• Rainbows!

• Phusion Passenger

• Heroku

Rack

Rack middleware

Rails Merb Sinatra Ramaze

Apache lighttpd Thin Unicorn

Rack handlers

Mongrel

Perl ?

Perl ?PSGIPerl Web Server Gateway Interface

Interface

InterfacePSGI != Plack

PSGI applicationcode reference$app = sub {...};

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

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

CGI-like environment variables+ psgi.input, psgi.errors etc.


HTTP status code (int.): 200, 404 etc.


Array reference of header pairs:[ ‘Content-Type’, ‘text/html’, ... ]


String, array reference of content chunks,Filehandle or IO::Handle-ish object

That’s it.(There’s a callback based streaming interface as well)

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

Now you’ve gota PSGI compatible

application.

Apache IIS lighttpd

CGI.pm

CGI fastcgimod_perl

JiftyMason Catalyst

Mason::CGIHandlerCatalyst::Engine


CGI::App

PSGI Compatible App

Plack::Middleware

Catalyst CGI::App Jifty Mason 2

Apache lighttpd HTTP::Server::PSGI Perlbalmod_psgi

Plack::Handler::* (CGI, FCGI, Apache)

PSGI Compatible App

Plack::Middleware

Catalyst CGI::App Jifty Mason 2



other PSGI Webservers

Web Servers

Plack::HandlerConnects PSGI compatible apps

to Web servers...

FCGIPlack::Handler::FCGI

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


ApachePlack::Handler::Apache1Plack::Handler::Apache2





StarmanUNIX Preforking HTTP servers (like Unicorn.rb)

HTTP/1.1 chunk + keep-alives / Very Fast

HTTP::Server::Simple::PSGIZero-deps other than HTTP::Server::Simple

Best for embedding PSGI applications

StarletSimpler UNIX HTTP/1.0 Server

Best used with Server::Starter and nginx/lighttpd

TwiggyNon-blocking web server (like Thin.rb)

based on AnyEvent framework

Perlbal pluginhttp://github.com/miyagawa/Perlbal-Plugin-PSGI



nginx embedded perlhttp://github.com/yappo/nginx-psgi-patchs

http://github.com/Yappo/nginx-psgi-patches

http://github.com/Yappo/nginx-psgi-patches

mod_psgihttp://github.com/spiritloose/mod_psgi

Apache2

http://github.com/spiritloose/mod_psgi




Gepokhttp://metacpan/module/Gepok

Pure Perl standalone HTTPSFirst released July 2011

evpsgihttp://github.com/sekimura/evpsgi

Feersumhttp://github.com/stash/Feersum

uWSGIhttp://projects.unbit.it/uwsgi/

CoronaCoroutine for each connection

based on Coro.pm

http://github.com/sekimura/evpsgi






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

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

PSGI

Plack::Middleware

Frameworks Apps Your own code


PSGI

Plack::Middleware

Frameworks Apps Your own code



Starman Twiggy uWSGI Corona etc, etc

25+ Plack::Handlers

Adoption?

PSGI Compatible App

Plack::Middleware



Starman Twiggy uWSGI Corona etc

PSGI Compatible App

Plack::Middleware



?


Catalyst Maypole Mason Mojo Sledge Spoon PageKit AxKit Egg Gantry Continuity Solstice Mojolicious

Tripletail Konstrukt Reaction Jifty Cyclone3 WebGUIOpenInteract Squatting Dancer CGI::Application

Nanoa Ark Angelos Noe Schenker Tatsumaki Amon Apache2::WebApp Web::Simple Apache2::REST

SweetPea Hydrant Titanium

• Amon

• Angelos

• Ark

• Catalyst

• CGI::Application

• Continuity

• Dancer

• Hydrant

• Jifty

• Mason

• Maypole

• Mojo

• Mojolicious

• Noe

• Schenker

• Sledge

• Squatting

• Tatsumaki

• Titanium

• Web::Simple

PSGI Perl Frameworks

ApplicationsMovable Type 6

WebGUI 8RT4

ACT (conference toolkit)Bricolage (if someone gets time)

PSGI Compatible App

Plack::Middleware



Starman Twiggy uWSGI Corona evpsgi

PSGI Compatible App

Plack::Middleware



Starman Twiggy uWSGI Corona evpsgi

Catalyst CGI::App Jifty Tatsumaki

Dancer Mojoliscious MT6 Mason 2

Web::Simple WebGui 8 Mojo etc...

PSGI from a framework

use Dancer;

get ‘/’ => sub { “Hello World”;};

dance;

use Mojolicious::Lite;

get ‘/:name’ => sub { my $self = shift; $self->render_text(‘Hello!’);};

app->start;

use My::Jifty::App;

my $app = My::Jifty::App->psgi_app;

use Web::Simple ‘MyApp’;

package MyApp;

dispatch { sub(GET) { [ 200, [...], [ ‘Hello’ ] ]; }};

my $app = MyApp->as_psgi;

use My::Catalyst::App;

My::Catalyst::App->setup_engine(‘PSGI’);

my $app = sub {

My::Catalyst::App->run(@_)

};

catalyst.pl My::Catalyst::App

Plack“PSGI implementation & toolkit”

Plack toolkit

Plack toolkitPlack::Handlers Connect PSGI apps and Web Servers

Plack toolkit

plackup Command line launcher

Plack::Handlers Connect PSGI apps and Web Servers

Plack toolkit


Plack::Loader (auto)load Plack Servers


Plack toolkit




Plack::Middleware Easy-to-use PSGI Middleware

Plack toolkit





Plack::Builder OO & DSL to enable Middleware

Plack toolkit





Plack::Apps Apps


Plack toolkit





Plack::Apps Apps

Plack::Test Testing


plackupRuns PSGI app instantly from CLI

(inspired by rackup)

> plackup app.psgi

> plackup app.psgiHTTP::Server::PSGI: Accepting connections at http://0:5000/

http://0:5000

http://0:5000

HTTP::Server::PSGIReference PSGI web server

bundled in Plack

Standalone, single-process HTTP servergreat for development and testing

Plack::Middleware(160+ modules - July 2011)

MiddlewareDebug, Session, Logger, Static, Lint,

AccessLog, ErrorDocument, StackTrace, Auth::Basic, Auth::Digest, ReverseProxy, Refresh, Auth::OAuth,

Throttle....

Access AccessLog AccessLog::Timed Acme::YadaYada AddDefaultCharset AllowCrossSiteAJAX AMF Assets Auth::Digest Auth::Form Auth::Htpasswd Auth::Negotiate Auth::Basic AutoRefresh BufferedStreaming Cache Cached ChromeFrame Chunked Class::Refresh Compile Conditional ConditionalGET ConsoleLogger ContentLength ContentMD5 CrossOrigin CSRFBlock Dancer::Debug DBIC::QueryLog Debug Debug::CatalystPluginCache Debug::DBIC::QueryLog Debug::DBIProfile Debug::Profiler::NYTProf Debug::W3CValidate Deflater DoCoMoGUID Doorman ErrorDocument ESI ETag Expires File::Sass Firebug::Lite FirePHP ForceEnv Head Header HTMLify HTMLMinify HTTPExceptions IEnosniff IIS6ScriptNameFix Image::Scale Inline InteractiveDebugger IPAddressFilter iPhone JavaScript::Ectype JSConcat JSONP LighttpdScriptNameFix Lint Log::Contextual Log::Minimal Log4perl LogDispatch LogWarn MethodOverride Mirror NeverExpire NoDeflate NoMultipleSlashes NullLogger Options OptionsOK Precompressed ProxyMap RearrangeHeaders Recursive RefererCheck Refresh REPL Reproxy ReverseProxy Rewrite Runtime Scope::Container Scope::Session ServerStatus::Lite Session Session::SerializedCookie SetAccept SimpleContentFilter SimpleLogger SizeLimit SocketIO SSI StackTrace Static Static::Minifier StaticShared Status Test::StashWarnings Throttle TMT UseChromeFrame Watermark

Plack MiddlewareWraps a PSGI applicationto add pre/post processing

Logging

LoggingStatus code redirect

LoggingStatus code redirectError Handler

LoggingStatus code redirectError HandlerCache Middleware

LoggingStatus code redirectError HandlerCache MiddlewareSession Middleware

LoggingStatus code redirectError HandlerCache MiddlewareSession MiddlewareRoutes Middleware

LoggingStatus code redirectError HandlerCache MiddlewareSession MiddlewareRoutes MiddlewareYour App

Plack::Middleware::A

Plack::Middleware::B

PSGI Compatible App


Request in


PSGI Compatible App

P::MW::A


Request in


PSGI Compatible App

P::MW::B

P::MW::A


Request in


PSGI Compatible App

PSGI App

P::MW::B

P::MW::A


Request in


PSGI Compatible App

P::MW::B

PSGI App

P::MW::B

P::MW::A


Request in


PSGI Compatible App

P::MW::A

P::MW::B

PSGI App

P::MW::B

P::MW::A


Request in


PSGI Compatible App

Response out

P::MW::A

P::MW::B

PSGI App

P::MW::B

P::MW::A


Request in


PSGI Compatible App

e.g. Redirect Response out

P::MW::A

P::MW::B

PSGI App

P::MW::B

P::MW::A


Request in


PSGI Compatible App

e.g. Redirect

e.g. Static

Response out

P::MW::A

P::MW::B

PSGI App

P::MW::B

P::MW::A


Request in


PSGI Compatible App

Enabling Plack::Middleware

reusable and extensible Middleware framework

Plack::Builder DSL in .psgi

my $app = sub { return [ $status, $header, $body ];};

use Plack::Builder;

return builder { enable “A”; enable “B”; $app;}


use Plack::Builder;

return builder { enable “A”; # Plack::Middleware::A enable “B”; # Order matters $app;}


use Plack::Builder;

return builder { enable “A”; enable “B”; $app;}


use Plack::Builder;

return builder { enable “Static”, root => “/htdocs”, path => qr!^/static/!; enable “Deflater”; $app;}


use Plack::Builder;

return builder { enable “Static”, root => “/htdocs”, path => qr!^/static/!; enable “Deflater”; # gzip/deflate $app;}


use Plack::Builder;

return builder { enable “Static”, root => “/htdocs”, path => qr!^/static/!; enable “Deflater”; $app;}

Plack::Middleware::Static

Plack::Middleware::Deflate

PSGI Compatible App


Request in


PSGI Compatible App

Static


Request in


PSGI Compatible App

=~ ^/static Response out

Static


Request in


PSGI Compatible App


-

Static


Request in


PSGI Compatible App


PSGI App

-

Static


Request in


PSGI Compatible App


Deflate compresses

PSGI App

-

Static


Request in


PSGI Compatible App


-

Deflate compresses

PSGI App

-

Static


Request in


PSGI Compatible App

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

MiddlewareWrite once, run in every framework

A few demos..

Assume...

use Plack::Builder;

my $body = ‘<html><body>Hello World</body></html>’;

my $app = sub { my $self = shift;

return [200, ['Content-Type' => 'text/html'], [ $body ]];};

Debugger

return builder { # Precious debug info. Right on your page! enable 'Debug';

$app;}

InteractiveDebugger

my $app = sub { my $foo = 'bar'; die "oops" if $foo eq 'bar';

[200, ['Content-Type' => 'text/html'], [ $body ]];};

return builder { # Enable Interactive debugging enable "InteractiveDebugger";

$app;}

NYTProf - profiler

First rule of Program Optimisation

Don’t do it!

Second rule of Program Optimisation

(for experts only)

Don’t do it - yet!

return builder { enable 'Debug', panels => [ [ 'Profiler::NYTProf' ] ]; $app;};

ServerStatus::Lite

use Plack::Builder;

return builder { enable "ServerStatus::Lite", path => '/server-status', allow => [ '127.0.0.1'], scoreboard => '/tmp/score'; $app;}

SizeLimit

use Plack::Builder;

return builder { enable "SizeLimit", max_unshared_size_in_kb => 3000, check_every_n_requests => 5; $app;}

Plack::App::*ready-to-use applications

Apache::ActionWrapper CGIBin Cascade CocProxy DAV Directory Directory::Xslate FCGIDispatcher File ImageMagick JSP PSGIBin Path::Router Proxy Proxy::Backend::AnyEvent::HTTP Proxy::Backend::LWP Proxy::Selective Proxy::Test URLMap WrapApacheReq WrapApacheReq::FakeRequest WrapCGI

Plack::App::CGIBinmount /cgi-bin as PSGI applications

CGI::PSGIEasy migration from CGI.pm

Plack::App::DirectoryStatic content file server

Plack::App::Proxy(non-blocking) proxy server

Can be used as reverse proxy as well

Plack::App::JSPRuns JavaScript PSGI apps :)

# app.psgi - Javascript! Plack::App::JSP->new( js => q{ function respond(body) { return [ 200, [ 'Content-type', 'text/html' ], [ body ] ] } respond("Five factorial is " + (function(x) { if ( x<2 ) return x; return x * arguments.callee(x - 1); })(5) ); });

Plack::App::URLMapMultiplex multiple apps

Integrated with Builder DSL

use CatApp;use CGIApp;

my $c1 = sub { CatApp->run };my $c2 = sub { CGIApp->run_psgi };

use Plack::Builder;

return builder { mount “/cat” => $c1; mount “/cgi-app” => builder { enable “StackTrace”; $c2; };}

Some more demos...

Basic website

TemplateToolkit + Static

my $root = '/path/to/html_doc_root';

my $app = Plack::Middleware::TemplateToolkit->new( INCLUDE_PATH => root,)->to_app;

return builder {

enable 'Static', path =>

qr{\.[gif|png|jpg|swf|ico|mov|mp3|pdf|js|css]$}, root => $root;

$app; }

Creating utilities

Caching Proxy

Website

Website

Developing code

Website

Developing code

Slow website

Slow website

Developing code

Slow website

Developing code

Caching Proxy

use Plack::Middleware::Cache;use Plack::App::Proxy;

my $app = Plack::App::Proxy->new(

remote => "http://london.pm.org/" )->to_app;

return builder { enable "Cache", match_url => '^/.*', # everything cache_dir => '/tmp/plack-cache'; $app;};

http://london.pm.org


use LWP::Simple;

my $content = get(‘http://localhost:5000/’);

http://localhost:5000


Caching Proxy + Domain hijack

use LWP::Simple;

my $content = get(‘http://localhost:5000/’);



use LWP::Simple;

my $content = get(‘http://london.pm.org/’);





return builder { enable "Cache", match_url => '^/.*', # everything cache_dir => '/tmp/plack-cache2'; $app;};





$app = builder { enable "Cache", match_url => '^/.*', # everything cache_dir => '/tmp/plack-cache2'; $app;};



# Hijack Any LWP::Useragent requestsLWP::Protocol::PSGI->register($app);

use LWP::Simple;

my $content = get("http://london.pm.org/");

say '\o/' if $content =~ /London Perl Mongers/;



Plack::TestUnified interface to write TAP testswith Mock HTTP and Live HTTP

use Plack::Test;use HTTP::Request::Common;


test_psgi app => $app,client => sub { my $callback = shift;

my $req = GET “http://localhost/foo”; my $res = $callback->($req); ok $res->[0] == ‘200’, ‘Success’; };

http://localhost/foo


use Plack::Test;use HTTP::Request::Common;


test_psgi app => $app,client => sub { my $callback = shift;

my $req = GET “http://localhost/foo”; my $res = $callback->($req);

ok $res->[0] == ‘200’, ‘Success’; };



Test::WWW::Mechanize::PSGI

use Test::WWW::Mechanize::PSGI; my $mech = Test::WWW::Mechanize::PSGI->new( app => $app, );

$mech->get_ok('/');

https://metacpan.org/module/Test::WWW::Mechanize::PSGI

https://metacpan.org/module/Test::WWW::Mechanize::PSGI

Testing your full configuration!

Network setup tip

Use a reverse proxy

• Sits in front of servers, not clients - “reverse”

Use a reverse proxy


•Makes servers more efficient

Use a reverse proxy



• Add HTTPS easily

Use a reverse proxy



• Add HTTPS easily

•Makes scaling easier

Use a reverse proxy

Webserver App

Internet / Users

Webserver App

Internet / Users

Reverse ProxyNGINX Perlbal Pound

Server


Server 1


Server 2

Server 1


Server 2

Server 3

Plack::Middleware::ReverseProxy

Updates $env->{REMOTE_ADDRESS}

Why use Plack?

Why use Plack?

‣ Flexibility

‣ Middleware

‣ Apps

‣ Development

‣ Testing

‣ Deployment

Flexibility




Flexibility• Easy to change webserver (25+!)




Flexibility• Easy to change webserver (25+!)



• Starman seems to be used most


Middleware

Middleware

• Easy to reuse with any PSGI app

Middleware


• Many tools to make your life easy

Middleware


• Many tools to make your life easy

• 160+ on CPAN now

App

• URLMapping / Routing

App


• Static files

App


• Static files

• Proxying

Development

Development

• plackup

Development

• plackup

• Restarter (monitor changes on disk)

Development

• plackup


• HTTP::Server::PSGI

Development

• plackup



• Debugging middleware

Development

• plackup



• Debugging middleware

• Profiler

Testing

Testing

• Testing your full configuration

Testing


• Test::WWW::Mechanize::PSGI

Testing


• Test::WWW::Mechanize::PSGI

• Plack::Test

Deployment

Deployment

• No separate configuration files

Deployment


• Easy to choose/change webserver

Deployment


• Easy to choose/change webserver

• DotCloud etc - cloud deployment

Summary

Summary

✦ PSGI is an interface, Plack is the code.

Summary


✦ Many fast PSGI servers.

Summary



✦ Adapters and tools for frameworks and webservers.

Summary




✦ An amazing amount of middleware

Summary




✦ An amazing amount of middleware

✦ Used in many production systems

Use Plack

Thank you!Slides: http://slideshare.net/ranguard

http://plackperl.org/

irc://irc.perl.org/#plack

http://slideshare.net/ranguard

http://slideshare.net/ranguard

http://plackperl.org

http://plackperl.org

Plack basics for Perl websites - YAPC::EU 2011

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