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package Koha::Middleware::Throttle; |
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# This file is part of Koha. |
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# |
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# Koha is free software; you can redistribute it and/or modify it |
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# under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# Koha is distributed in the hope that it will be useful, but |
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# WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with Koha; if not, see <http://www.gnu.org/licenses>. |
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|
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use Modern::Perl; |
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|
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use parent qw(Plack::Middleware); |
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use Plack::Response; |
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use Plack::Util::Accessor qw(debug interface allow_list paths request_threshold last_n_minutes cidr_block); |
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use Net::Netmask; |
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|
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use C4::Templates; |
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use Koha::Caches; |
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|
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=head1 Functions |
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|
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=head2 prepare_app |
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|
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Called at startup time |
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|
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=cut |
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|
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sub prepare_app { |
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my $self = shift; |
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|
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if ( !$self->request_threshold ) { |
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|
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#NOTE: Give a high fallback request threshold |
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$self->request_threshold(50); |
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} |
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if ( !( $self->last_n_minutes && $self->last_n_minutes > 1 ) ) { |
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|
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#NOTE: Give a reasonable fallback number of last N minutes to check for visits |
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$self->last_n_minutes(5); |
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} |
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my $allowed_cidr_blocks = { |
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8 => 1, |
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16 => 1, |
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24 => 1, |
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32 => 1, |
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}; |
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if ( $self->cidr_block ) { |
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if ( !$allowed_cidr_blocks->{ $self->cidr_block } ) { |
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$self->cidr_block(24); |
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} |
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} else { |
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$self->cidr_block(24); |
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} |
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} |
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|
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=head2 call |
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|
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Called at request time |
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|
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=cut |
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|
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sub call { |
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my ( $self, $env ) = @_; |
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|
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#NOTE: Like the CSRF middleware, we only apply this once in the request cycle. |
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#NOTE: We don't apply it to errordocument subrequests. |
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if ( !$env->{'plack.middleware.Koha.Throttle'} ) { |
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|
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my $ip_address = $env->{REMOTE_ADDR}; |
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|
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my $throttle_check = 0; |
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my $threshold = $self->request_threshold; |
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|
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my $req = Plack::Request->new($env); |
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my $request_path = $req->path // q{}; |
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my $user_agent = $req->user_agent // q{-}; |
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|
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my $paths = $self->paths(); |
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if ( $paths && ref $paths && ref $paths eq 'ARRAY' ) { |
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foreach my $path (@$paths) { |
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|
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#NOTE: Since we're using flexible regex, we have to iterate through a list rather than using a more efficient hash lookup |
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if ( $request_path =~ qr{$path} ) { |
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$throttle_check = 1; |
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last; |
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} |
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} |
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} |
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|
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if ($throttle_check) { |
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|
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#NOTE: If this request requires a throttle check, we first check out allow_list for exceptions |
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if ( $self->allow_list |
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&& ref $self->allow_list |
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&& ref $self->allow_list eq 'ARRAY' ) |
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{ |
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foreach my $ip_range ( @{ $self->allow_list } ) { |
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if ( $self->debug ) { |
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warn "Checking IP address '$ip_address' against IP range '$ip_range'\n"; |
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} |
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my $mask = Net::Netmask->new2($ip_range); |
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if ($mask) { |
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if ( $mask->match($ip_address) ) { |
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if ( $self->debug ) { |
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warn "IP address '$ip_address' matched IP range '$ip_range'. Skip.\n"; |
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} |
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$throttle_check = 0; |
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last; |
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} |
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} |
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} |
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} |
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} |
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|
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if ($throttle_check) { |
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my $total_visits = $self->_get_total_visits( |
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{ |
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ip_address => $ip_address, |
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} |
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); |
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if ( $self->debug ) { |
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warn "Total visits during time period: $total_visits\n"; |
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warn "Visit threshold: $threshold\n"; |
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} |
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if ( $total_visits > $threshold ) { |
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my $error = sprintf( "Throttled! IPADDRESS{{%s}} USERAGENT{{%s}}\n", $ip_address, $user_agent ); |
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warn $error; |
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my $output; |
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my $template = $self->_prepare_template( { template_filename => 'opac-throttled.tt' } ); |
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if ($template) { |
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$output = $template->output(); |
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} |
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my $res = Plack::Response->new( 200, [ 'Content-Type' => 'text/plain' ], ["Throttled!"] ); |
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if ($output) { |
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$res->content_type('text/html'); |
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$res->body($output); |
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} |
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return $res->finalize; |
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} |
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} |
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|
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} else { |
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$env->{'plack.middleware.Koha.Throttle'} = 'checked'; |
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} |
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return $self->app->($env); |
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} |
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sub _get_total_visits { |
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my ( $self, $args ) = @_; |
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my $total_visits = 0; |
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my $ip_address = $args->{ip_address}; |
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#NOTE: `memcdump --servers=memcached | grep "throttle"` should show you all the throttle cache keys but it's not... |
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my $cache = Koha::Caches->get_instance('throttle'); |
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if ( $ip_address && $cache ) { |
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my $cache_obj = $cache->{memcached_cache}; |
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if ( $cache_obj && ref $cache_obj && ref $cache_obj eq 'Cache::Memcached::Fast::Safe' ) { |
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my $cidr = sprintf( "%s/%d", $ip_address, $self->cidr_block ); |
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my ($ip_range) = Net::CIDR::cidr2octets($cidr); |
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|
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#my $ip_range = join('.',(split /\./, $ip_address)[0..2]); |
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my $cache_keys = $self->_generate_cache_keys( |
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{ |
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ip_range => $ip_range, |
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} |
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); |
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my $current_cache_key = $cache_keys->[0]; |
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my $get = $cache_obj->get($current_cache_key); |
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if ( !$get ) { |
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#FIXME: Improve expiry time configuration |
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#FIXME: Should this time be relative to the time of the cache key's minute-truncated time rather based from now? |
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my $expiry_secs = $self->last_n_minutes * 60; |
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if ( $self->debug ) { |
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warn sprintf( |
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"Cache key %s expires in %s seconds (%s minutes)\n", $current_cache_key, $expiry_secs, |
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$self->last_n_minutes |
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); |
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} |
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$cache_obj->set( $current_cache_key, 0, $expiry_secs ); |
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} |
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my $rv = $cache_obj->incr($current_cache_key); |
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my $results = $cache_obj->get_multi(@$cache_keys); |
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my @sorted_keys = sort { $b cmp $a } keys %$results; |
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foreach my $key (@sorted_keys) { |
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my $value = $results->{$key}; |
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if ($value) { |
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if ( $self->debug ) { |
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my ( $key_ip_range, $key_time ) = split( ':', $key ); |
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warn sprintf( |
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"IP range '%s' Time '%s' -> %s visits\n", $key_ip_range, |
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scalar localtime($key_time), $value |
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); |
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} |
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$total_visits += int($value); |
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} |
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} |
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} |
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} |
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return $total_visits; |
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} |
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sub _get_truncated_timestamp { |
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my ( $self, $args ) = @_; |
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my $time = time; # Get the current time as a Unix timestamp |
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$time -= $time % 60; # Truncate by minute interval |
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return $time; |
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} |
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sub _generate_cache_keys { |
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my ( $self, $args ) = @_; |
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my $ip_range = $args->{ip_range}; |
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my @cache_keys = (); |
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if ($ip_range) { |
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my $now = $self->_get_truncated_timestamp(); |
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if ($now) { |
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#Default to last 5 minutes |
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my $last_n_minutes = $self->last_n_minutes; |
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my $max_bound = ( $last_n_minutes - 1 ); |
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if ( $self->debug ) { |
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warn "Check visits over the last $last_n_minutes minutes\n"; |
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} |
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foreach my $minus_minutes ( 0 .. $max_bound ) { |
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my $timestamp = $now; |
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if ($minus_minutes) { |
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$timestamp -= ( $minus_minutes * 60 ); |
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} |
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my $expanded_time = scalar localtime($timestamp); |
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if ( $self->debug ) { |
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warn "Considered time slot: $expanded_time\n"; |
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} |
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my $cache_key = sprintf( "%s:%s", $ip_range, $timestamp ); |
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push( @cache_keys, $cache_key ); |
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} |
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} |
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} |
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return \@cache_keys; |
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} |
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sub _prepare_template { |
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my ( $self, $args ) = @_; |
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my $template; |
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my $interface = $self->interface; |
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my $template_filename = $args->{template_filename}; |
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if ( $interface && $template_filename ) { |
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#NOTE: See Koha::Template in BZ 31380 |
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$template = C4::Templates::gettemplate( $template_filename, $interface ); |
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} |
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return $template; |
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} |
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1; |