[management] return empty array instead of null on networks endpoints (#3480)

Author: pascal-fischer

management/server/http/handlers/networks/handler.go

@@ -289,7 +289,7 @@ func (h *handler) collectIDsInNetwork(ctx context.Context, accountID, userID, ne
 }
 
 func (h *handler) generateNetworkResponse(networks []*types.Network, routers map[string][]*routerTypes.NetworkRouter, resourceIDs map[string][]string, groups map[string]*nbtypes.Group, account *nbtypes.Account) []*api.Network {
-	var networkResponse []*api.Network
+	networkResponse := make([]*api.Network, 0, len(networks))
 	for _, network := range networks {
 		routerIDs, peerCounter := getRouterIDs(network, routers, groups)
 		policyIDs := account.GetPoliciesAppliedInNetwork(network.ID)

management/server/http/handlers/networks/resources_handler.go

@@ -89,7 +89,7 @@ func (h *resourceHandler) getAllResourcesInAccount(w http.ResponseWriter, r *htt
 
 	grpsInfoMap := groups.ToGroupsInfoMap(grps, 0)
 
-	var resourcesResponse []*api.NetworkResource
+	resourcesResponse := make([]*api.NetworkResource, 0, len(resources))
 	for _, resource := range resources {
 		resourcesResponse = append(resourcesResponse, resource.ToAPIResponse(grpsInfoMap[resource.ID]))
 	}

management/server/http/handlers/networks/routers_handler.go

@@ -48,7 +48,7 @@ func (h *routersHandler) getAllRouters(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	var routersResponse []*api.NetworkRouter
+	routersResponse := make([]*api.NetworkRouter, 0, len(routers))
 	for _, router := range routers {
 		routersResponse = append(routersResponse, router.ToAPIResponse())
 	}