Prettify json on manager conf export (#2292)

lemonldap-ng-common/lib/Lemonldap/NG/Common/Conf/RESTServer.pm

@@ -769,8 +769,8 @@ sub metadata {
         return $self->sendJSONresponse(
             $req,
             $self->currentConf,
-            forceJSON => 1,
-            headers   => [
+            pretty  => 1,
+            headers => [
                 'Content-Disposition' => "Attachment; filename=lmConf-$c.json"
             ],
         );

lemonldap-ng-common/lib/Lemonldap/NG/Common/PSGI.pm

@@ -125,7 +125,23 @@ sub sendJSONresponse {
     $args{headers} ||= [ $req->spliceHdrs ];
     my $type = 'application/json; charset=utf-8';
     if ( ref $j ) {
-        eval { $j = $_json->encode($j); };
+        eval {
+            if ( $args{pretty} ) {
+
+                # This avoids changing the settings of the $_json reference
+                $j = to_json(
+                    $j,
+                    {
+                        allow_nonref => 1,
+                        pretty       => 1,
+                        canonical    => 1
+                    }
+                );
+            }
+            else {
+                $j = $_json->encode($j);
+            }
+        };
         return $self->sendError( $req, $@ ) if ($@);
     }
     return [ $args{code}, [ 'Content-Type' => $type, @{ $args{headers} } ],