Bug 37893: (QA follow-up): Check if port already in use when storing a listener

To test:
1) Ensure a port is already in use in the server
2) Try creating a new listener using that same port.
3) Notice the error 'Something went wrong: Error: Can't listen on port 127.0.0.1:8023/tcp/IPv4. Port already in use.' is shown on the UI

Co-authored-by: Martin Renvoize <martin.renvoize@openfifth.co.uk>
Signed-off-by: Andrew Fuerste Henry <andrew@bywatersolutions.com>
Signed-off-by: Lisette Scheer <lisette@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@openfifth.co.uk>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

Koha/REST/V1/SIP2/Listeners.pm

@@ -108,6 +108,12 @@ sub add {
                     openapi => { error => "Given " . $to_api_mapping->{ $_->parameter } . " does not exist" }
                 );
             }
+            elsif ( $_->isa('Koha::Exceptions::ObjectNotCreated') ) {
+                return $c->render(
+                    status  => 500,
+                    openapi => { error => $_->error }
+                );
+            }
         }
 
         $c->unhandled_exception($_);

Koha/SIP2/Listener.pm

@@ -19,6 +19,8 @@ use Modern::Perl;
 
 use base qw(Koha::Object);
 
+use IO::Socket;
+
 =head1 NAME
 
 Koha::SIP2::Listener- Koha Sip Listener Object class
@@ -29,6 +31,34 @@ Koha::SIP2::Listener- Koha Sip Listener Object class
 
 =cut
 
+=head3 store
+
+store
+
+=cut
+
+sub store {
+    my ($self) = @_;
+
+    my ($port) = $self->port =~ /:(\d+)/;
+    my ($addr) = $self->port =~ /([0-9.]+)/;
+
+    my $socket = IO::Socket::INET->new(
+        LocalAddr => $addr,
+        LocalPort => $port,
+        Proto     => 'tcp',
+        ReuseAddr => 0,
+        Listen    => 1
+    );
+
+    unless ($socket) {
+        Koha::Exceptions::ObjectNotCreated->throw(
+            error => "Can't listen on port " . $self->port . ". Port already in use." );
+    }
+
+    return $self->SUPER::store;
+}
+
 =head3 get_for_config
 
 Returns the listener hashref as expected by C4/SIP/Sip/Configuration->new;