Using Quartz Scheduler In ASP.NET Core

Here, we will learn about using a Quartz scheduler in ASP.NET Core. The scheduler is very useful for running tasks in the background. For example, we have to write in a file every 5 min, so the simplest method will be to create a schedule to write in a file. so that it can be called at every 5 min.

Prerequisites:

• Basic knowledge of ASP.NET Core and C#

Create a new project in ASP.NET Core.

Open the Package Manager Console and type the following command in it.

Install-Package Quartz

Create a new folder namely “Schedulers”. you can use your own name.

Now, inside this “Schedulers” folder create a new class namely “JobSchedule”, and paste the below code there.

using System;

namespace Faisal.Schedulers
{
    public class JobSchedule
    {
        public JobSchedule(Type jobType, string cronExpression)
        {
            JobType = jobType;
            CronExpression = cronExpression;
        }

        public Type JobType { get; }
        public string CronExpression { get; }
    }
}

inside the same “Schedulers” folder create a new class namely “QuartzHostedService” which inherits from “IHostedService”, and paste the below code there.

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;
using Quartz;
using Quartz.Spi;

namespace Faisal.Schedulers
{
    public class QuartzHostedService : IHostedService
    {
        private readonly ISchedulerFactory _schedulerFactory;
        private readonly IJobFactory _jobFactory;
        private readonly IEnumerable<JobSchedule> _jobSchedules;

        public QuartzHostedService(
            ISchedulerFactory schedulerFactory,
            IJobFactory jobFactory,
            IEnumerable<JobSchedule> jobSchedules)
        {
            _schedulerFactory = schedulerFactory;
            _jobSchedules = jobSchedules;
            _jobFactory = jobFactory;
        }
        public IScheduler Scheduler { get; set; }

        public async Task StartAsync(CancellationToken cancellationToken)
        {
            Scheduler = await _schedulerFactory.GetScheduler(cancellationToken);
            Scheduler.JobFactory = _jobFactory;

            foreach (var jobSchedule in _jobSchedules)
            {
                var job = CreateJob(jobSchedule);
                var trigger = CreateTrigger(jobSchedule);

                await Scheduler.ScheduleJob(job, trigger, cancellationToken);
            }

            await Scheduler.Start(cancellationToken);
        }

        public async Task StopAsync(CancellationToken cancellationToken)
        {
            await Scheduler?.Shutdown(cancellationToken);
        }

        private static IJobDetail CreateJob(JobSchedule schedule)
        {
            var jobType = schedule.JobType;
            return JobBuilder
                .Create(jobType)
                .WithIdentity(jobType.FullName)
                .WithDescription(jobType.Name)
                .Build();
        }

        private static ITrigger CreateTrigger(JobSchedule schedule)
        {
            return TriggerBuilder
                .Create()
                .WithIdentity($"{schedule.JobType.FullName}.trigger")
                .WithCronSchedule(schedule.CronExpression)
                .WithDescription(schedule.CronExpression)
                .Build();
        }
    }
}

Create a new class namely “SingletonJobFactory” inside the same folder, and copy the below code and paste inside that file.

using Microsoft.Extensions.DependencyInjection;
using Quartz;
using Quartz.Spi;
using System;

namespace Faisal.Schedulers
{
    public class SingletonJobFactory : IJobFactory
    {
        private readonly IServiceProvider _serviceProvider;
        public SingletonJobFactory(IServiceProvider serviceProvider)
        {
            _serviceProvider = serviceProvider;
        }

        public IJob NewJob(TriggerFiredBundle bundle, IScheduler scheduler)
        {
            return _serviceProvider.GetRequiredService(bundle.JobDetail.JobType) as IJob;
        }

        public void ReturnJob(IJob job) { }
    }
}

Now we have done with Quartz setup files, Now let’s create a new class to call/schedule our code. To do that create new class anywhere. I’ll use the same folder and will give class name as “RemindersJob”, which inherits from “IJob” interface.

The below code will execute the as per scheduler time which we will set in startup class. You need to write your own code which you want to execute in the scheduler.

Below is my “RemindersJob” class code. which write in files at every 5 minutes.

using Quartz;
using System;
using System.IO;
using System.Threading.Tasks;

namespace Faisal.Schedulers
{
    public class RemindersJob : IJob
    {
        private readonly IServiceProvider _provider;
        private readonly IEmailSender _emailSender;
        public RemindersJob(IServiceProvider provider, IEmailSender emailSender)
        {
            _provider = provider;
            _emailSender = emailSender;
        }

        public Task Execute(IJobExecutionContext context)
        {
            Logs($"{DateTime.Now} [Reminders Service called]" + Environment.NewLine);
            
            return Task.CompletedTask;
        }      
        public void Logs(string message)
        {
            var path = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot", "Quartz");
            if (!Directory.Exists(path))
            {
                Directory.CreateDirectory(path);
            }
            path = Path.Combine(path, "Logs.txt");
            using FileStream fstream = new FileStream(path, FileMode.Create);
            using TextWriter writer = new StreamWriter(fstream);
            writer.WriteLine(message);
        }
    }
}

We have done all code. now we just need to set a timer for service, for that, we need to add the below code in the startup class inside the “ConfigureServices” method.

// Add Quartz services
services.AddHostedService<QuartzHostedService>();
services.AddSingleton<IJobFactory, SingletonJobFactory>();
services.AddSingleton<ISchedulerFactory, StdSchedulerFactory>();

// Add our job
services.AddSingleton<RemindersJob>();
services.AddSingleton(new JobSchedule(
    jobType: typeof(RemindersJob),
    cronExpression: "0 0/5 * 1/1 * ? *")); // run every 5 min

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