package Plack::Middleware;
use strict;
use warnings;
use Carp ();
use parent qw(Plack::Component);
use Plack::Util;
use Plack::Util::Accessor qw( app );

sub import {
    my $class = shift;
    if (@_) {
        Carp::carp("use Plack::Middleware qw(Foo) is deprecated. See perldoc Plack::Builder");
    }
}

sub wrap {
    my($self, $app, @args) = @_;
    if (ref $self) {
        $self->{app} = $app;
    } else {
        $self = $self->new({ app => $app, @args });
    }
    return $self->to_app;
}

1;

__END__

=head1 NAME

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

=head1 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;
  };

=head1 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 C<call> method (or C<to_app> method
that would return the PSGI code reference) to do the actual work. You
can use C<< $self->app >> to call the original (wrapped) application.

See L<Plack::Builder> how to actually enable middlewares in your
I<.psgi> application file using the DSL. If you do not like our
builder DSL, you can also use C<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);

=head1 SEE ALSO

L<Plack> L<Plack::Builder>

=cut