Question

我使用Topshelf的Owin Web服务器启动休息服务器。在同一个服务中，我想启动一个后台任务来轮询（是的，我必须轮询！）一个数据库，用于＆＃34;云命令＆＃34;然后将数据写入锁定代码中的云。

此代码似乎在一段时间后停止处理owin请求（它们似乎被拒绝），我不知道为什么？

StartMethod调用CheckForCloudCommandsForever，后者又在无限循环中调用ProcessPostedCommands。我参考了代码中嵌入的研究，以展示我如何到达今天的代码。

启动背景无限循环的正确方法是什么？

公共类WebServer { 私人IDisposable _webapp;

    // Do not call with await for it to loop forever
    private async Task CheckForCloudCommandsForever()
    {
        InitCloud();
        var cmdRdr = new FwCommandReader();

        while (true)
        {
            // do the work in the loop
            string newData = DateTime.Now.ToLongTimeString();

            //GlobalLogger.Logger.Debug($"In Loop {newData}");
            cmdRdr.ProcessPostedCommands();

            // don't run again for at least x milliseconds
            await Task.Delay(3000);
        }
    }


    public void Start()
    {


        // https://blogs.msdn.microsoft.com/benwilli/2016/06/30/asynchronous-infinite-loops-instead-of-timers/

        // invoke loop method but DO NOT await it so the rest of the program can run
        CheckForCloudCommandsForever();


        //  _webapp = WebApp.Start<Startup>("http://*:8080");
        /*
         * from SO http://stackoverflow.com/questions/21634333/hosting-webapi-using-owin-in-a-windows-service
         */
        StartOptions options = new StartOptions();

        //string portPrime = "52017";
        string portPrime = FWUtils.ConfigUtils.SrcPort();

        options.Urls.Add("http://*:" + portPrime);
        string machineAndPort = $"http://{Environment.MachineName}:{portPrime}";
        options.Urls.Add(machineAndPort);

        Console.WriteLine($"FWShowServer starting up on URL={machineAndPort}.");

        try
        {
        _webapp = WebApp.Start<Startup>(options);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            Console.WriteLine($"Service could not open on Port={machineAndPort}, Make sure you are a system admin or perhaps the port is already used.  Create and or edit the server config file to specify an unused port.");
            throw;
        }

    }

public void ProcessPostedCommands（） { 使用（var showContext = new ShowContext（）） {

            var commands = showContext.CloudCommands
                .Where(c => !showContext.CloudCommandsProcessed
                    .Select(p => p.CloudCommandsPKID)
                    .Contains(c.Pkid)
                )
                //.OrderByDescending( c => c.SubmittedAt)
                .OrderBy( c => c.SubmittedAt)
                .ToList();

            foreach (var command in commands)
            {
                lock (cloudLock)
                {
                    if (executingTask == null || executingTask.IsCompleted)
                    {
                        executingTask = ProcessCommandAsync(showContext, command);
                    }
                }
                executingTask.Wait();
            }
        }
    }

在C＃中使用Owin WebServer时运行后台循环

0 个答案: