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lib/Amon2/Plugin/Web/JSON.pm  view on Meta::CPAN

package Amon2::Plugin::Web::JSON;
use strict;
use warnings;
use JSON 2 qw/encode_json/;
use Amon2::Util ();

my $_JSON = JSON->new()->ascii(1);

my %_ESCAPE = (
    '+' => '\\u002b', # do not eval as UTF-7
    '<' => '\\u003c', # do not eval as HTML
    '>' => '\\u003e', # ditto.
);

sub init {
    my ($class, $c, $conf) = @_;
    unless ($c->can('render_json')) {
        Amon2::Util::add_method($c, 'render_json', sub {
            my ($c, $stuff) = @_;

            # for IE7 JSON venularity.
            # see http://www.atmarkit.co.jp/fcoding/articles/webapp/05/webapp05a.html
            my $output = $_JSON->canonical( $conf->{canonical} ? 1 : 0 )->encode($stuff);
            $output =~ s!([+<>])!$_ESCAPE{$1}!g;

            my $user_agent = $c->req->user_agent || '';

            # defense from JSON hijacking
            if ((!$c->request->header('X-Requested-With')) && $user_agent =~ /android/i && defined $c->req->header('Cookie') && ($c->req->method||'GET') eq 'GET') {
                my $res = $c->create_response(403);
                $res->content_type('text/html; charset=utf-8');
                $res->content("Your request may be JSON hijacking.\nIf you are not an attacker, please add 'X-Requested-With' header to each request.");
                $res->content_length(length $res->content);
                return $res;
            }

            my $res = $c->create_response(200);

            my $encoding = $c->encoding();
            $encoding = lc($encoding->mime_name) if ref $encoding;
            $res->content_type("application/json; charset=$encoding");
            $res->header( 'X-Content-Type-Options' => 'nosniff' ); # defense from XSS
            $res->content_length(length($output));
            $res->body($output);

            if (defined (my $status_code_field =  $conf->{status_code_field})) {
                $res->header( 'X-API-Status' => $stuff->{$status_code_field} ) if exists $stuff->{$status_code_field};
            }

            return $res;
        });
    }
}

1;
__END__

=encoding utf-8

=head1 NAME

Amon2::Plugin::Web::JSON - JSON plugin

=head1 SYNOPSIS

    use Amon2::Lite;

    __PACKAGE__->load_plugins(qw/Web::JSON/);

    get '/' => sub {
        my $c = shift;
        return $c->render_json(+{foo => 'bar'});
    };

    __PACKAGE__->to_app();

=head1 DESCRIPTION

This is a JSON plugin.

=head1 METHODS

=over 4

=item C<< $c->render_json(\%dat); >>

Generate JSON data from C<< \%dat >> and returns instance of L<Plack::Response>.

=back

=head1 PARAMETERS

=over 4

=item status_code_field

It specify the field name of JSON to be embedded in the 'X-API-Status' header.
Default is C<< undef >>. If you set the C<< undef >> to disable this 'X-API-Status' header.

    __PACKAGE__->load_plugins(
        'Web::JSON' => { status_code_field => 'status' }