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Plack::Middleware.3pm

NAME

Plack::Middleware - Base class for easy-to-use PSGI middleware

SYNOPSIS

   package Plack::Middleware::Foo;
   use parent qw( Plack::Middleware );
 
   sub call {
       my($self, $env) = @_;
       # Do something with $env
 
       # $self->app is the original app
       my $res = $self->app->($env);
 
       # Do something with $res
       return $res;
   }
 
   # then in app.psgi
   use Plack::Builder;
 
   my $app = sub { ... } # as usual
 
   builder {
       enable "Plack::Middleware::Foo";
       enable "Plack::Middleware::Bar", %options;
       $app;
   };
 
 

DESCRIPTION

Plack::Middleware is an utility base class to write PSGI middleware. All you have to do is to inherit from Plack::Middleware and then implement the callback "call" method (or "to_app" method that would return the PSGI code reference) to do the actual work. You can use "$self->app" to call the original (wrapped) application.

See Plack::Builder how to actually enable middlewares in your .psgi application file using the DSL. If you do not like our builder DSL, you can also use "wrap" method to wrap your application with a middleware:

   use Plack::Middleware::Foo;
 
   my $app = sub { ... };
   $app = Plack::Middleware::Foo->wrap($app, %options);
   $app = Plack::Middleware::Bar->wrap($app, %options);
 
 

SEE ALSO

Plack Plack::Builder