Bug 19410: Add Koha::Objects->search_for_api

Following the discussion about the best way to make things simpler for
developing the REST api, I quote Lari's email:

"As many other endpoint will have the exact same usage, by looking at your example, I would prefer to avoid writing parameter / pagination / sorting / header handling for each list operation in our API controllers. Do you think it's possible to centralize all of this e.g. by passing $c into a customized search sub? Perhaps in Koha::Objects?
so instead we could have something like (ignore my bad choice of naming)...:
sub list_vendors {
  my $c = shift->openapi->valid_input or return;
  my $args = $c->validation->output;
  my $vendors;

  return try {
    $vendors = Koha::Acquisition::Booksellers->api_list_search($c);
    return $c->render(status => 200, openapi => $vendors);
  } catch {
    ...
  }
}"

We all agreed we neeed something like that. Here's a possible implementation. I take
advantage of the previously written Mojo helpers, that are fully covered by tests.

I submit this early so anyone can take a look and gather ideas to make it even better.
I'm already using it (effectively) for the /acquisitions/orders endpoint I'm writing
on bug 18731.

Thanks!

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>

Signed-off-by: Lari Taskula <lari.taskula@jns.fi>

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>

Koha/Objects.pm

@@ -23,6 +23,7 @@ use Carp;
 use List::MoreUtils qw( none );
 
 use Koha::Database;
+use Koha::Exceptions;
 
 =head1 NAME
 
@@ -170,6 +171,88 @@ sub search_related {
     }
 }
 
+=head3 search_for_api
+
+    my @objects = Koha::Objects->earch_for_api( $c );
+
+Searches for objects given a controller object I<$c>.
+
+=cut
+
+sub search_for_api {
+    my ( $self, $c ) = @_;
+
+    my $args = $c->validation->output;
+    my $attributes;
+
+    # Extract reserved params
+    my ( $filtered_params, $reserved_params ) = $c->extract_reserved_params($args);
+
+    # Merge sorting into query attributes
+    $c->dbic_merge_sorting(
+        {
+            attributes => $attributes,
+            params     => $reserved_params
+        }
+    );
+
+    # Merge pagination into query attributes
+    $c->dbic_merge_pagination(
+        {
+            attributes => $attributes,
+            params     => $reserved_params
+        }
+    );
+
+    # Perform search
+    my $objects = $self->search( $filtered_params, $attributes );
+    $c->add_pagination_headers({ total => $objects->count, params => $args })
+        if $objects->is_paged;
+
+    return $objects;
+}
+
+=head2 _build_query_params_from_api
+
+    my $params = _build_query_params_from_api( $filtered_params, $reserved_params );
+
+Builds the params for searching on DBIC based on the selected matching algorithm.
+Valid options are I<contains>, I<starts_with>, I<ends_with> and I<exact>. Default is
+I<contains>. If other value is passed, a Koha::Exceptions::WrongParameter exception
+is raised.
+
+=cut
+
+sub _build_query_params_from_api {
+
+    my ( $filtered_params, $reserved_params ) = @_;
+
+    my $params;
+    my $match = $reserved_params->{_match} // 'contains';
+
+    foreach my $param ( keys %{$filtered_params} ) {
+        if ( $match eq 'contains' ) {
+            $params->{$param} =
+              { like => '%' . $filtered_params->{$param} . '%' };
+        }
+        elsif ( $match eq 'starts_with' ) {
+            $params->{$param} = { like => $filtered_params->{$param} . '%' };
+        }
+        elsif ( $match eq 'ends_with' ) {
+            $params->{$param} = { like => '%' . $filtered_params->{$param} };
+        }
+        elsif ( $match eq 'exact' ) {
+            $params->{$param} = $filtered_params->{$param};
+        }
+        else {
+            Koha::Exceptions::WrongParameter->throw(
+                "Invalid value for _match param ($match)");
+        }
+    }
+
+    return $params;
+}
+
 =head3 single
 
 my $object = Koha::Objects->search({}, { rows => 1 })->single