在 Asp.NET core 中触发 Quartz 作业时释放上下文

Question

我正在尝试从 .NET 核心中的 Web API 控制器构建触发器 Quartz 作业。 我已经成功地通过 Startup 类的简单时间表创建了一个触发器：

 public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IServiceProvider services)
        {
            loggerFactory.AddConsole(this.Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            app.UseCors("CorsPolicy");

            app.UseApplicationInsightsRequestTelemetry();
            app.UseApplicationInsightsExceptionTelemetry();

            app.UseMvc();

            ProcessTracksScheduler.Start(services);          
        }

这里是启动方法：

 public static class ProcessTracksScheduler
    {
        public static void Start(IServiceProvider provider)
        {
            try
            {
                ISchedulerFactory schedFact = new StdSchedulerFactory();
                IScheduler sched = schedFact.GetScheduler();
                sched.Start();

                IJobDetail job = JobBuilder.Create<ProcessTracksJob>()
                    .WithIdentity("ProcessTracks", "Group1")
                    .Build();

                job.JobDataMap["tracksService"] = provider.GetService(typeof(ITracksService));
                job.JobDataMap["cloudService"] = provider.GetService(typeof(ICloudService));
                job.JobDataMap["broadcastService"] = provider.GetService(typeof(IBroadcastService));
                job.JobDataMap["categoriesService"] = provider.GetService(typeof(ICategoriesService));

                ITrigger trigger = TriggerBuilder.Create()
                    .WithSimpleSchedule(x => x
                        .RepeatForever()
                        .WithInterval(TimeSpan.FromDays(1)))
                    .StartNow()
                    .Build();

                sched.ScheduleJob(job, trigger);

            }
            catch (ArgumentException e)
            {
                // Log the error
            }
        }
   }

还有工作：

public async void Execute(IJobExecutionContext context)
{
    var tracksService = context.MergedJobDataMap["tracksService"] as ITracksService;
    var cloudService = context.MergedJobDataMap["cloudService"] as ICloudService;
    var broadcastService = context.MergedJobDataMap["broadcastService"] as IBroadcastService;
    var categoryService = context.MergedJobDataMap["categoriesService"] as ICategoriesService;

    if (tracksService == null || cloudService == null || broadcastService == null || categoryService == null)
        return;

    var broadcasts = broadcastService.GetAll();
    // Some more work to do.
}

所以这个按预期工作，我很满意！但这里的问题是，当我试图构建一个触发器以使该作业仅从我的 Web API 控制器启动一次时：

[Route("Proccess")]
[HttpPost]
public async Task<IActionResult> ProccessTracks()
{
    ProcessTracksScheduler.StartOnce(serviceProvider);
    return Ok("Job scheduled");
}

和StartOnce方法，基本和Start一样：

public static void StartOnce(IServiceProvider provider)
{
    try
    {
        ISchedulerFactory schedFact = new StdSchedulerFactory();
        IScheduler sched = schedFact.GetScheduler();
        sched.Start();

        IJobDetail job = JobBuilder.Create<ProcessTracksJob>()
            .WithIdentity("ProcessTracksOnce", "Group1")
            .Build();

        job.JobDataMap["tracksService"] = provider.GetService(typeof(ITracksService));
        job.JobDataMap["cloudService"] = provider.GetService(typeof(ICloudService));
        job.JobDataMap["broadcastService"] = provider.GetService(typeof(IBroadcastService));
        job.JobDataMap["categoriesService"] = provider.GetService(typeof(ICategoriesService));

        ITrigger trigger = TriggerBuilder.Create()
            .StartNow()
            .Build();

        sched.ScheduleJob(job, trigger);

    }
    catch (ArgumentException e)
    {
        // Log the error
    }
}

但是当我的工作被执行时，var broadcasts = broadcastService.GetAll(); 行抛出一个异常，说我的 DbContext 已被释放..

DbContext 通过 DI 传递到使用 ASP.Net-Core 的控制器/服务：

// In Startup.cs
public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(this.Configuration.GetConnectionString("MyConnString")));
    services.AddTransient<IBroadcastService, BroadcastsService>();
    // Add the others services.        
}

我尝试了很多东西，但找不到任何解决此问题的方法。

Answer 1

您是否尝试在构造函数中要求 ProcessTracksJob 类中的服务？我就是这样用的，没问题。

插入使用JobDataMap试试这样：

public class ProcessTracksJob :IJob 
{
   private readonly ITracksService _tracksService;

   public ProcessTracksJob(ITracksService tracksService, etc.) 
   {
     _tracksService = tracksService;
     ...
   }

   /// the execute method using the private fields in this class

}