176 lines
4.6 KiB
Perl
176 lines
4.6 KiB
Perl
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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=head2 Mojolicious::Plugin methods
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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 $c carries, following RFC5988, including
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the following relation types: 'prev', 'next', 'first' and 'last'.
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It also adds X-Total-Count, containing the total results count.
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If page size is omitted, it defaults to the value of the RESTdefaultPageSize syspref.
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=cut
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$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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C4::Context->preference('RESTdefaultPageSize') // 20;
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# do we need to paginate?
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return $c unless $req_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 $c;
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}
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);
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=head3 dbic_merge_pagination
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$filter = $c->dbic_merge_pagination({
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filter => $filter,
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params => {
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page => $params->{_page},
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per_page => $params->{_per_page}
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}
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});
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Adds I<page> and I<rows> elements to the filter parameter.
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=cut
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$app->helper(
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'dbic_merge_pagination' => sub {
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my ( $c, $args ) = @_;
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my $filter = $args->{filter};
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$filter->{page} = $args->{params}->{_page};
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$filter->{rows} = $args->{params}->{_per_page};
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return $filter;
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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;
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