How To Find Out Your Background Check For Free

A few years dorsum Phil Haack wrote a great article on the dangers of recurring background tasks in ASP.Net. In it he points out a few gotchas that are And so common when folks try to do piece of work in the background. Read it, merely hither's a summary from his post.

An unhandled exception in a thread non associated with a request volition take downwardly the process.
If you run your site in a Web Farm, yous could end up with multiple instances of your app that all attempt to run the same task at the same time.
The AppDomain your site runs in tin can become downward for a number of reasons and have downwards your background task with information technology.

If you recollect yous tin can only write a background task yourself, it's probable you'll get it wrong. I'k not impugning your skills, I'm merely saying it's subtle. Plus, why should yous accept to?

There's LOT of great means for you to exercise things in the background and a lot of libraries and choices bachelor.

Some ASP.Internet apps will be hosted in IIS in your data middle and others volition exist hosted in the Azure cloud. The spectrum of usage is roughly this, in my opinion:

General: Hangfire (or similar similar open up source libraries)
- used for writing background tasks in your ASP.Internet website
Cloud: Azure WebJobs
- A formal Azure characteristic used for offloading running of groundwork tasks exterior of your Website and calibration the workload
Avant-garde: Azure Worker Role in a Cloud Service
- scale the background processing workload independently of your Website and yous demand control over the motorcar

In that location'due south lots of swell manufactures and videos on how to use Azure WebJobs, and lots of documentation on how Worker Roles in scalable Azure Cloud Services work, but not a lot about how your hosted ASP.Net application and hands take a groundwork service. Here's a few.

WebBackgrounder

Equally it says "WebBackgrounder is a proof-of-concept of a web-farm friendly groundwork chore manager meant to just work with a vanilla ASP.NET spider web application." Its code hasn't been touched in years, But the WebBackgrounder NuGet packet has been downloaded almost a half-million times.

The goal of this project is to handle one task but, manage a recurring chore on an interval in the groundwork for a spider web app.

If your ASP.NET awarding just needs one background job to runs an a bones scheduled interval, than maybe yous but need the nuts of WebBackgrounder.

using Organization;
using System.Threading;
using Organisation.Threading.Tasks;namespace WebBackgrounder.DemoWeb
{
            public course SampleJob : Job
            {
            public SampleJob(TimeSpan interval, TimeSpan timeout)
            : base("Sample Task", interval, timeout)
            {
            }
                      public override Task Execute()
            {
            return new Task(() => Thread.Sleep(3000));
            }
            }
}

Built in: QueueBackgroundWorkItem - Added in .Internet 4.5.2

Somewhat in response to the need for WebBackgrounder, .Net iv.five.2 added QueueBackgroundWorkItem as a new API. Information technology's non just a "Chore.Run," it tries to exist more:

QBWI schedules a task which tin run in the background, contained of any request. This differs from a normal ThreadPool work detail in that ASP.NET automatically keeps track of how many piece of work items registered through this API are currently running, and the ASP.Cyberspace runtime will try to delay AppDomain shutdown until these work items take finished executing.

Information technology can try to delay an AppDomain for as long as ninety seconds in order to permit your task to complete. If you can't finish in ninety seconds, and then you'll demand a different (and more robust, meaning, out of process) technique.

The API is pretty straightforward, taking Func<CancellationToken, Task>. Here'southward an instance that kicks of a groundwork piece of work detail from an MVC activeness:

public ActionResult SendEmail([Bind(Include = "Name,Electronic mail")] User user)
{
          if (ModelState.IsValid)
          {
          HostingEnvironment.QueueBackgroundWorkItem(ct => SendMailAsync(user.Email));
          return RedirectToAction("Index", "Abode");
          }            render View(user);
}

FluentScheduler

FluentScheduler is a more sophisticated and complex scheduler that features a (you guessed it) fluent interface. You accept really explicit command over when your tasks run.

using FluentScheduler;public class MyRegistry : Registry
{
            public MyRegistry()
            {
            // Schedule an ITask to run at an interval
            Schedule<MyTask>().ToRunNow().AndEvery(two).Seconds();
                      // Schedule a simple chore to run at a specific time
            Schedule(() => Panel.WriteLine("Timed Job - Volition run every day at 9:15pm: " + DateTime.Now)).ToRunEvery(i).Days().At(21, fifteen);
                      // Schedule a more complex action to run immediately and on an monthly interval
            Schedule(() =>
            {
            Panel.WriteLine("Complex Action Task Starts: " + DateTime.Now);
            Thread.Sleep(chiliad);
            Console.WriteLine("Complex Activity Job Ends: " + DateTime.Now);
            }).ToRunNow().AndEvery(1).Months().OnTheFirst(DayOfWeek.Monday).At(3, 0);
            }
}

FluentScheduler besides embraces IoC and can easily plug into your favorite Dependency Injection tool of choice by just implementing their ITaskFactory interface.

Quartz.Cyberspace

Quartz.Internet is a .NET port of the pop Java job scheduling framework of the (almost) aforementioned name. It's very actively adult. Quartz has an IJob interface with merely one method, Execute, to implement.

using Quartz;
using Quartz.Impl;
using Organization;namespace ScheduledTaskExample.ScheduledTasks
{
            public course JobScheduler
            {
            public static void Beginning()
            {
            IScheduler scheduler = StdSchedulerFactory.GetDefaultScheduler();
            scheduler.Start();
                      IJobDetail job = JobBuilder.Create<MyJob>().Build();
                      ITrigger trigger = TriggerBuilder.Create()
            .WithDailyTimeIntervalSchedule
            (south =>
            due south.WithIntervalInHours(24)
            .OnEveryDay()
            .StartingDailyAt(TimeOfDay.HourAndMinuteOfDay(0, 0))
            )
            .Build();
                      scheduler.ScheduleJob(job, trigger);
            }
            }
}

So, inside your Application_Start, you telephone call JobScheduler.Start(). At that place'due south a great getting started article on Quartz at Mikesdotnetting you should check out.

Hangfire

And last but definitely not least, the most polished (IMHO) of the group, Hangfire by @odinserj. It'southward a fantastic framework for background jobs in ASP.Cyberspace. Information technology'due south even optionally backed past Redis, SQL Server, SQL Azure, MSMQ, or RabbitMQ for reliability.

The Hangfire documentation is amazing, really. Every open source project's document should be this polished. Heck, ASP.Internet'southward documentation should exist this proficient.

The best characteristic from Hangfire is its built in /hangfire dashboard that shows you all your scheduled, processing, succeeded and failed jobs. It'due south really a nice polished addition.

You can enqueue "fire and forget" jobs hands and they are backed by persistent queues:

BackgroundJob.Enqueue(() => Console.WriteLine("Burn-and-forget"));

You tin can delay them...

BackgroundJob.Schedule(() => Console.WriteLine("Delayed"), TimeSpan.FromDays(1));

Or great very sophisticated CRON style recurrent tasks:

RecurringJob.AddOrUpdate(() => Console.Write("Recurring"), Cron.Daily);

Hangfire is simply a joy.

Check out the Hangfire Highlighter Tutorial for a sophisticated but easy to follow existent-world case.

At that place'southward a rich ecosystem out there prepare to aid you with your groundwork tasks. All these libraries are first-class, are open source, and are available every bit NuGet Packages.

Did I miss your favorite? Audio off in the comments!

Sponsor: Many thank you to my friends at Raygun for sponsoring the feed this week. I *dearest* Raygun and use it myself. It'due south astonishing. Become notified of your software's bugs as they happen! Raygun.io has error tracking solutions for every major programming language and platform - Starting time a free trial in nether a minute!

Virtually Scott

Scott Hanselman is a former professor, quondam Chief Architect in finance, at present speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-upward comic, a cornrower, and a book author.

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