Angelos github.com/dann dann

How to developModern WAF

danntechmemo@gmail.com

YAPC::Asia 2009 2009/09/10

Angelos github.com/dann dann

About Me

•Dann

•Creator of Angelos

•Yet Another WAF

•http://github.com/dann/

Angelos github.com/dann dann

Presentation Overview•What is modern web application framework?

•How to develop the minimal elements of modern WAF

•How to develop the plugin architecture of WAF

Angelos github.com/dann dann

What is modern WAF?

•Fullstack like Rails•Pluggable like Plagger•Server Abstraction like WSGI

•Separete WAF and App

Usability

Extendability

Testability

Angelos github.com/dann dann

How to developthe basic elements

of WAF

Angelos github.com/dann dann

The basic elements

ComponentManagerDispatcher

Enginerecieve a request and return a

response(Server Abstraction)

URL to Controller resolver Load and search component

Angelos github.com/dann dann

Basic Sequence of WAF

②①

③

④⑤

⑥

Angelos github.com/dann dann

Engine - Angelos::Engine

sub build_engine { my $self = shift; my $request_handler = $self->request_handler; $request_handler ||= $self->build_request_handler;

return Angelos::PSGI::Engine->new( interface => { module => $self->server, .... }, psgi_handler => $request_handler, ); } psgi handler which is passed to

the server gateay

the type of server gateway

Angelos github.com/dann dann

Engine - Angelos::PSGI::Engine

use Mouse;use Angelos::Types qw( ServerGateway ); has 'interface' => (    is => 'ro',    isa => ServerGateway,    coerce => 1,); has 'psgi_handler' => ( is => 'rw', ); sub run {    my $self = shift;    $self->interface->run( $self->psgi_handler );}

pass psgi handler to server gateway

Create Server Gateway

Angelos github.com/dann dann

Create Server Gateway

package Angelos::PSGI::ServerGatewayBuilder;use strict;use warnings;use Plack::Loader;

sub build { my ( $class, $module, $args ) = @_; my $server_gateway = Plack::Loader->load( $module, %{$args} ); $server_gateway;}

Create server gateway with Plack::Loader

Angelos github.com/dann dann

psgi handler’s code

...sub { my $env = shift; my $req = Angelos::Request->new($env); my $res = $self->handle_request($req); my $psgi_res = $self->finalize_response($res); return $psgi_res;}...

return PSGI response

recieve PSGI envand convert it to WAF Request

Angelos github.com/dann dann

Request Handler - Angelos::Engine::Base

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

eval { $self->DISPATCH($req); }; if ( my $e = Exception::Class->caught() ) { $self->HANDLE_EXCEPTION($e); }

# return response return $self->context->res;}

②dispatch request to

Dispatcher

①recive a request

Angelos github.com/dann dann

Dispatchingsub DISPATCH { my ( $self, $req ) = @_;

my $dispatch = $self->dispatcher->dispatch($req); ...

$dispatch->run;

# return response $c->res;}

② Dispatch a request do dispatcher

Angelos github.com/dann dann

Angelos::Dispatchersub dispatch { my ( $self, $request ) = @_;

my $match = $self->router->match($request);

my $dispatch = $self->dispatch_class->new( match => $match ); return $dispatch;}

③ <URL to Controller>search controller name based on the request path with HTTP::Router

④ Create dispatch instance

Angelos github.com/dann dann

Angelos::Dispatcher::Dispatch

my $controller = $match->params->{controller};

my $controller_instance = $self->find_controller_instance( { context => $c, controller => $controller, }); ...

$controller_instance->_dispatch_action( $action, $params );

⑤ search a controller instance from Component Manager

⑥ execute Controller’s action and return response.

Angelos github.com/dann dann

Routing

HTTP::Router->define( sub { $_->match('/')->to( { controller => 'Root', action => 'index' } ); $_->resources('Book'); } );

conf/routes.pl- define routing information

Angelos github.com/dann dann

Routing Table.----------------------------------------------+------------+------------+--------------.| path | method | controller | action |+---------------------------------------------+------------+------------+------------+| / | | Root | index || /book.{format} | POST | Books | create || /book | POST | Books | create || /book.{format} | GET | Books | index || /book | GET | Books | index || /book/new.{format} | GET | Books | post || /book/new | GET | Books | post || /book/{book_id}.{format} | GET | Books | show || /book.{format} | POST | Books | create || /book | POST | Books | create || /book.{format} | GET | Books | index || /book.{bookk_id}.{format} | DELETE | Books | destroy || /book/{book_id} | DELETE | Books | destroy || /book/{book_id}.{format} | PUT | Books | update || /book/{book_id} | PUT | Books | update |'-----------------------------------------------+------------+------------+-------------

Angelos github.com/dann dann

Finished developing basic elements of WAF

•It’s really easy to develop basic elements of WAF

•You can develop simple WAF like Sinatra in 4 or 5 hours

Angelos github.com/dann dann

How to develop the plugin architecture of WAF

Angelos github.com/dann dann

How to development the plugin architecture of WAF

• What the plugin architecture of WAF SHOULD be

• The type of Plugins

• How to develop plugin architecture of WAF

• Example: the plugin of Angelos

Angelos github.com/dann dann

What the plugin architecture of WAF SHOULD

• the core elements of WAF should be as small as possible and the all parts of WAF should be extendable and pluggable

• The scope of plugin should be limeted

• Controller, View, Middleware, Request, Response

• Extension point must be declaretive

Angelos github.com/dann dann

The types of Plugins

•Hook WAF’s Lifecycle

•Add methods to WAF’s class

Angelos github.com/dann dann

Plugin Implementation

• Hook WAF’s lifecycle• Mouse’s Role + method modifier• Class::Trigger• MouseX::Object::Pluggable

• Add methods to WAF’s classes• Mouse’s Role• Exporter• Multiple inheritance

Angelos github.com/dann dann

How to develop plugin in Angelos

• Make Plugin as Role

• User consume plugins in the WAF Component

• Hook WAF’s lifecycle with method modifier

• hook Component’s hook point

• Declare hook point method with CAPITAL character

Angelos github.com/dann dann

Hook point example

sub _dispatch_action { my ( $self, $action, $params ) = @_; ...

eval { $self->ACTION( $self->context, $action, $params ); }; ...

}

Declare hook point with Capital character

Angelos github.com/dann dann

the code of Pluginbefore 'ACTION' => sub { my ( $self, $c, $action, $params ) = @_; $self->__action_start_time( time() );};

after 'ACTION' => sub { my ( $self, $c, $action, $params ) = @_; $self->__action_end_time( time() );

my $elapsed = $self->__action_end_time - $self->__action_start_time; my $message = "action processing time:\naction: $action \ntime : $elapsed secs\n"; $self->log->info($message);};

Angelos github.com/dann dann

What The WAF developer should do

• WAF developer should make default plugin sets which user should use

• if there aren’t default plugins sets...

• How can I use Unicode in WAF?

• ... UseXXX, YYY...

• How can I inflate datetime? ...

Angelos github.com/dann dann

Conclusion• The basic elements of WAF

• Engine, Dispatcher, Component Loader

• WAF’s plugin

• Hook WAF Lifecycle or add a Method to the Component of WAF

• Plugin Scope must be limited

• the plugin and plugins default sets should be provided by WAF developer

Angelos github.com/dann dann

Fin.

• It’s really easy to implement WAF now

• Let’s develop modern WAF with us ;)

• Repository

• http://github.com/dann/angelos/tree/master