Push notification Parse.com后台推送通知未运行

我正试图通过Parse.com发送后台推送通知，以ping我的服务器：

-(void) application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler
{
    [PFPush handlePush:userInfo];

    if (application.applicationState == UIApplicationStateInactive) {
            [PFAnalytics trackAppOpenedWithRemoteNotificationPayload:userInfo];
    }

    NSString *CustomData = [userInfo objectForKey:@"CustomField"];

    // ping server to confirm the push notification is delivered, sometimes this is called but not always
    [[DAL sharedInstance] log:CustomData onComplete:nil];

    // do stuff
    if([CustomData isEqualToString:@"CustomItem"])
    {
            // do stuff
    }

当我通过Parse.com的RESTAPI向发送推送通知时

我收到警报，服务器被ping，但是如果我删除警报

{ "where":{"objectId":"[objectID]"}, "data":{"content-available":"1","CustomField":"CustomItem"} }

没有发生任何事情，服务器没有ping。如何在不可见的情况下发送推送通知，并且仍然ping服务器

{ "where":{"objectId":"[objectID]"}, "data":{"content-available":"1","CustomField":"CustomItem"} }