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package Plack::Middleware::Throttle;
use Moose;
use Carp;
use Scalar::Util;
use DateTime;
use Plack::Util;
our $VERSION = '0.01';
extends 'Plack::Middleware';
has code => ( is => 'rw', isa => 'Int', lazy => 1, default => '503' );
has message =>
( is => 'rw', isa => 'Str', lazy => 1, default => 'Over rate limit' );
has backend => ( is => 'rw', isa => 'Object', required => 1 );
has key_prefix =>
( is => 'rw', isa => 'Str', lazy => 1, default => 'throttle' );
has max => ( is => 'rw', isa => 'Int', lazy => 1, default => 100 );
has white_list =>
( is => 'rw', isa => 'ArrayRef', predicate => 'has_white_list' );
has black_list =>
( is => 'rw', isa => 'ArrayRef', predicate => 'has_black_list' );
has path => ( is => 'rw', isa => 'RegexpRef', predicate => 'has_path' );
sub prepare_app {
my $self = shift;
$self->backend( $self->_create_backend( $self->backend ) );
}
sub _create_backend {
my ( $self, $backend ) = @_;
if ( defined !$backend ) {
Plack::Util::load_class("Plack::Middleware::Throttle::Backend::Hash");
return Plack::Middleware::Throttle::Backend::Hash->new;
}
return $backend if defined $backend && Scalar::Util::blessed $backend;
die "backend must be a cache object";
}
sub call {
my ( $self, $env ) = @_;
my $res = $self->app->($env);
return $res unless $self->path_is_throttled($env);
return $res if $self->is_white_listed($env);
return $self->forbiden if $self->is_black_listed($env);
my $key = $self->cache_key($env);
my $allowed = $self->allowed($key);
if ( !$allowed ) {
$self->over_rate_limit();
}
else {
$self->response_cb(
$res,
sub {
my $res = shift;
$self->add_headers($res);
}
);
}
}
sub allowed {
return 1;
}
sub request_done {
return 1;
}
sub is_white_listed {
my ( $self, $env ) = @_;
return 0 if !$self->has_white_list;
my $ip = $env->{REMOTE_ADDR};
if ( grep { $_ == $ip } @{ $self->white_list } ) {
return 1;
}
return 0;
}
sub is_black_listed {
my ( $self, $env ) = @_;
return 0 if !$self->has_black_list;
my $ip = $env->{REMOTE_ADDR};
if ( grep { $_ == $ip } @{ $self->black_list } ) {
return 1;
}
return 0;
}
sub path_is_throttled {
my ( $self, $env ) = @_;
return 0 if !$self->has_path;
my $path_match = $self->path;
my $path = $env->{PATH_INFO};
for ($path) {
my $matched = 'CODE' eq ref $path_match ? $path_match->($_) : $_ =~ $path_match;
$matched ? return 1 : return 0;
}
return 0;
}
sub forbiden {
my $self = shift;
return [
403, [ 'Content-Type' => 'text/plain', ],
['your IP is black listed']
];
}
sub over_rate_limit {
my $self = shift;
return [
$self->code,
[
'Content-Type' => 'text/plain',
'X-RateLimit-Reset' => $self->reset_time
],
[ $self->message ]
];
}
sub add_headers {
my ( $self, $res ) = @_;
my $headers = $res->[1];
Plack::Util::header_set( $headers, 'X-RateLimit-Limit', $self->max );
Plack::Util::header_set( $headers, 'X-RateLimit-Reset',
$self->reset_time );
return $res;
}
sub client_identifier {
my ( $self, $env ) = @_;
if ( $env->{REMOTE_USER} ) {
return $self->key_prefix."_".$env->{REMOTE_USER};
}
else {
return $self->key_prefix."_".$env->{REMOTE_ADDR};
}
}
1;
__END__
=head1 NAME
Plack::Middleware::Throttle - A Plack Middleware for rate-limiting incoming HTTP requests.
=head1 SYNOPSIS
my $handler = builder {
enable "Throttle::Hourly",
max => 2,
backend => Plack::Middleware::Throttle::Backend::Hash->new(),
path => qr{^/foo};
sub { [ '200', [ 'Content-Type' => 'text/html' ], ['hello world'] ] };
};
=head1 DESCRIPTION
This is a C<Plack> middleware that provides logic for rate-limiting incoming
HTTP requests to Rack applications.
This middleware provides three ways to handle throttling on incoming requests :
=over 4
=item B<Hourly>
How many requests an host can do in one hour. The counter is reseted each hour.
=item B<Daily>
How many requets an host can do in one hour. The counter is reseted each day.
=item B<Interval>
Which interval of time an host must respect between two request.
=back
=head1 OPTIONS
=over 4
=item B<code>
HTTP code returned in the response when the limit have been exceeded. By default 503.
=item B<message>
HTTP message returned in the response when the limit have been exceeded. By defaylt "Over rate limit".
=item B<backend>
A cache object to store sessions informations.
backend => Redis->new(server => '127.0.0.1:6379');
or
backend => Cache::Memcached->new(servers => ["10.0.0.15:11211", "10.0.0.15:11212"]);
The cache object must implement B<get>, B<set> and B<incr> methods. By default, you can use C<Plack::Middleware::Throttle::Backend::Hash>.
By default, if no backend is specified, L<Plack::Middleware::Throttle::Backend::Hash> is used.
=item B<key_prefix>
Key to prefix sessions entry in the cache.
=item B<path>
URL pattern or a callback to match request to throttle. If no path is specified, the whole application will be throttled.
=item B<white_list>
An arrayref of hosts to put in a white list.
=item B<black_list>
An arrayref of hosts to put in a black list.
=back
=head1 AUTHOR
franck cuny E<lt>franck@lumberjaph.netE<gt>
=head1 SEE ALSO
=head1 LICENSE
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
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