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package Koha::REST::Plugin::Pagination; |
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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 under the |
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# terms of the GNU General Public License as published by the Free Software |
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# Foundation; either version 3 of the License, or (at your option) any later |
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# version. |
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# |
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# Koha is distributed in the hope that it will be useful, but WITHOUT ANY |
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR |
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# A PARTICULAR PURPOSE. See the 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 along |
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# with Koha; if not, write to the Free Software Foundation, Inc., |
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
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use Modern::Perl; |
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use Mojo::Base 'Mojolicious::Plugin'; |
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=head1 NAME |
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Koha::REST::Plugin::Pagination |
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=head1 API |
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|
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=head2 Mojolicious::Plugin methods |
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|
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=head3 register |
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=cut |
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sub register { |
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my ( $self, $app ) = @_; |
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=head2 Helper methods |
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=head3 add_pagination_headers |
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my $patrons = Koha::Patrons->search( ... ); |
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$c->add_pagination_headers({ |
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total => $patrons->count, |
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params => { |
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page => ... |
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per_page => ... |
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... |
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} |
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}); |
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Adds a Link header to the response message $c carries, following RFC5988, including |
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the following relation types: 'prev', 'next', 'first' and 'last'. |
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It also adds X-Total-Count, containing the total results count. |
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|
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=cut |
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$app->helper( |
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'add_pagination_headers' => sub { |
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my ( $c, $args ) = @_; |
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my $total = $args->{total}; |
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my $req_page = $args->{params}->{page}; |
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my $per_page = $args->{params}->{per_page}; |
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my $pages = int $total / $per_page; |
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$pages++ |
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if $total % $per_page > 0; |
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my @links; |
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if ( $pages > 1 and $req_page > 1 ) { # Previous exists? |
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push @links, |
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_build_link( |
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$c, |
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{ page => $req_page - 1, |
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per_page => $per_page, |
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rel => 'prev', |
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params => $args->{params} |
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} |
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); |
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} |
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if ( $pages > 1 and $req_page < $pages ) { # Next exists? |
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push @links, |
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_build_link( |
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$c, |
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{ page => $req_page + 1, |
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per_page => $per_page, |
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rel => 'next', |
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params => $args->{params} |
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} |
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); |
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} |
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push @links, |
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_build_link( $c, |
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{ page => 1, per_page => $per_page, rel => 'first', params => $args->{params} } ); |
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push @links, |
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_build_link( $c, |
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{ page => $pages, per_page => $per_page, rel => 'last', params => $args->{params} } ); |
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# Add Link header |
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$c->res->headers->add( 'Link' => join( ',', @links ) ); |
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# Add X-Total-Count header |
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$c->res->headers->add( 'X-Total-Count' => $total ); |
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return $c; |
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} |
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); |
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} |
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=head2 Internal methods |
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=head3 _build_link |
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my $link = _build_link( $c, { page => 1, per_page => 5, rel => 'prev' }); |
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Returns a string, suitable for using in Link headers following RFC5988. |
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=cut |
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sub _build_link { |
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my ( $c, $args ) = @_; |
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my $params = $args->{params}; |
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$params->{page} = $args->{page}; |
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$params->{per_page} = $args->{per_page}; |
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my $link = '<' |
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. $c->req->url->clone->query( |
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$params |
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)->to_abs |
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. '>; rel="' |
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. $args->{rel} . '"'; |
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# TODO: Find a better solution for this horrible (but needed) fix |
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$link =~ s|api/v1/app\.pl/||; |
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return $link; |
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} |
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1; |