Bug 27760: Add stash_overrides helper

This patch adds a simple helper that reads the x-koha-override request
header, and processes it to stash a hashref with the passed overrides.

No check on the overrides themselves is done, as they should be
validated using the OpenAPI spec.

To test:
1. Apply this patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/api/v1/auth_authenticate_api_request.t
=> SUCCESS: Tests pass!
3. Sign off :-D

Signed-off-by: David Nind <david@davidnind.com>

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

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

Koha/REST/Plugin/Query.pm

@@ -262,6 +262,34 @@ Merges parameters from $q_params into $filtered_params.
                     if $THE_embed;
             }
 
+            return $c;
+        }
+    );
+
+=head3 stash_overrides
+
+    $c->stash_overrides();
+
+=cut
+
+    $app->helper(
+        'stash_overrides' => sub {
+
+            my ( $c ) = @_;
+
+            my $override_header = $c->req->headers->header('x-koha-override');
+
+            my $overrides = {};
+
+            if ( $override_header ) {
+                my @overrides = ();
+                foreach my $override ( split /\s*,\s*/, $override_header ) {
+                    $overrides->{$override} = 1;
+                }
+            }
+
+            $c->stash( 'koha.overrides' => $overrides );
+
             return $c;
         }
     );

t/Koha/REST/Plugin/Query.t

@@ -255,6 +255,18 @@ get '/stash_embed_no_spec' => sub {
     };
 };
 
+get '/stash_overrides' => sub {
+    my $c = shift;
+
+    $c->stash_overrides();
+    my $overrides = $c->stash('koha.overrides');
+
+    $c->render(
+        status => 200,
+        json   => $overrides
+    );
+};
+
 sub to_model {
     my ($args) = @_;
     $args->{three} = delete $args->{tres}
@@ -264,7 +276,7 @@ sub to_model {
 
 # The tests
 
-use Test::More tests => 6;
+use Test::More tests => 7;
 use Test::Mojo;
 
 subtest 'extract_reserved_params() tests' => sub {
@@ -487,3 +499,16 @@ subtest 'stash_embed() tests' => sub {
       );
 
 };
+
+subtest 'stash_overrides() tests' => sub {
+
+    plan tests => 4;
+
+    my $t = Test::Mojo->new;
+
+    $t->get_ok( '/stash_overrides' => { 'x-koha-override' => 'any,none,some_other,any,' } )
+      ->json_is( { 'any' => 1, 'none' => 1, 'some_other' => 1 } ); # empty string and duplicates are skipped
+
+    $t->get_ok( '/stash_overrides' => { 'x-koha-override' => '' } )
+      ->json_is( {} ); # empty string is skipped
+};