Bug 14721: OAI-PMH must return error when no results

When getting records from OAI-PMH, an error must be returned if there is no results.

See : http://www.openarchives.org/OAI/openarchivesprotocol.html#ErrorConditions

Test plan :
- Enable OAI webservice
- Perform a query that will return no results. ie : /cgi-bin/koha/oai.pl?verb=ListRecords&metadataPrefix=marcxml&from=2099-12-30&until=2099-12-31
=> Without patch you get a response with :
   <ListRecords/>
=> With patch you get a response with error code :
   <error code="noRecordsMatch">No records match the given criteria</error>
- Check a good query returns still results
- Same test with ListIdentifiers verb

Signed-off-by: Mirko Tietgen <mirko@abunchofthings.net>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>

opac/oai.pl

@@ -411,6 +411,14 @@ sub new {
         ) );
     }
 
+    # Return error if no results
+    unless ($count) {
+        return HTTP::OAI::Response->new(
+            requestURL => $repository->self_url(),
+            errors     => [ new HTTP::OAI::Error( code => 'noRecordsMatch' ) ],
+        );
+    }
+
     return $self;
 }
 
@@ -586,6 +594,14 @@ sub new {
         }
     }
 
+    # Return error if no results
+    unless ($count) {
+        return HTTP::OAI::Response->new(
+            requestURL => $repository->self_url(),
+            errors     => [ new HTTP::OAI::Error( code => 'noRecordsMatch' ) ],
+        );
+    }
+
     return $self;
 }