TT#26652 addditional subscriberregistrations error checks

* return HTTP_UNPROCESSABLE_ENTRY if form data is not valid
      or a susbcriber is not found
    * POST: do not commit transaction if update_item fails

Change-Id: I7149922d4e4d701213ce351112cc67e611c3d910

lib/NGCP/Panel/Controller/API/SubscriberRegistrations.pm

@@ -139,7 +139,7 @@ sub POST :Allow {
 
         my ($guard, $txn_ok) = ($c->model('DB')->txn_scope_guard, 0);
         {
-            $self->update_item($c, undef, undef, $resource, $form, $create);
+            last unless $self->update_item($c, "new", undef, $resource, $form, $create);
 
             $guard->commit;
             $txn_ok = 1;

lib/NGCP/Panel/Role/API/SubscriberRegistrations.pm

@@ -187,8 +187,11 @@ sub update_item {
     );
 
     my $sub = $self->subscriber_from_id($c, $resource->{subscriber_id});
-    return unless $sub;
-    unless($create) {
+    unless ($sub) {
+        $self->error($c, HTTP_UNPROCESSABLE_ENTITY, "Could not find a subscriber with the provided subscriber_id");
+        return;
+    }
+    if ($item && ref $item && !$create) {
         $self->delete_item($c, $item);
     }
     my $cflags = 0;
@@ -211,10 +214,16 @@ sub update_item {
 sub fetch_item {
     my ($self, $c, $resource, $form, $old_item) = @_;
 
-    return unless $form;
+    unless ($form) {
+        $self->error($c, HTTP_UNPROCESSABLE_ENTITY, "Missing data values");
+        return;
+    }
 
     my $sub = $self->subscriber_from_id($c, $resource->{subscriber_id});
-    return unless $sub;
+    unless ($sub) {
+        $self->error($c, HTTP_UNPROCESSABLE_ENTITY, "Could not find a subscriber with the provided subscriber_id");
+        return;
+    }
 
     my $item;
     my $flush_timeout = 30;