Hangfire dependency injection with .net core

问题:

How can I use .net core's default dependency injection in Hangfire ?

I am new to Hangfire and searching for an example which works with asp.net core.

回答1:

See full example on GitHub https://github.com/gonzigonz/HangfireCore-Example.
Live site at http://hangfirecore.azurewebsites.net/

1. Make sure you have the Core version of Hangfire:
   dotnet add package Hangfire.AspNetCore

2. Configure your IoC by defining a JobActivator. Below is the config for use with the default asp.net core container service:

   public class HangfireActivator : Hangfire.JobActivator
   {
       private readonly IServiceProvider _serviceProvider;
   
       public HangfireActivator(IServiceProvider serviceProvider)
       {
           _serviceProvider = serviceProvider;
       }
   
       public override object ActivateJob(Type type)
       {
           return _serviceProvider.GetService(type);
       }
   }  
   

3. Next register hangfire as a service in the Startup.ConfigureServices method:

   services.AddHangfire(opt => 
       opt.UseSqlServerStorage("Your Hangfire Connection string"));
   

4. Configure hangfire in the Startup.Configure method. In relationship to your question, the key is to configure hangfire to use the new HangfireActivator we just defined above. To do so you will have to provide hangfire with the IServiceProvider and this can be achieved by just adding it to the list of parameters for the Configure method. At runtime, DI will providing this service for you:

   public void Configure(
       IApplicationBuilder app, 
       IHostingEnvironment env, 
       ILoggerFactory loggerFactory,
       IServiceProvider serviceProvider)
   {
       ...
   
       // Configure hangfire to use the new JobActivator we defined.
       GlobalConfiguration.Configuration
           .UseActivator(new HangfireActivator(serviceProvider));
   
       // The rest of the hangfire config as usual.
       app.UseHangfireServer();
       app.UseHangfireDashboard();
   }  
   

5. When you enqueue a job, use the registered type which usually is your interface. Don't use a concrete type unless you registered it that way. You must use the type registered with your IoC else Hangfire won't find it. For Example say you've registered the following services:

   services.AddScoped<DbManager>();
   services.AddScoped<IMyService, MyService>();
   

Then you could enqueue DbManager with an instantiated version of the class:

    BackgroundJob.Enqueue(() => dbManager.DoSomething());

However you could not do the same with MyService. Enqueuing with an instantiated version would fail because DI would fail as only the interface is registered. In this case you would enqueue like this:

    BackgroundJob.Enqueue<IMyService>( ms => ms.DoSomething());

回答2:

As far as I am aware, you can use .net cores dependency injection the same as you would for any other service.

You can use a service which contains the jobs to be executed, which can be executed like so

var jobId = BackgroundJob.Enqueue(x => x.SomeTask(passParamIfYouWish));

Here is an example of the Job Service class

public class JobService : IJobService
{
    private IClientService _clientService;
    private INodeServices _nodeServices;

    //Constructor
    public JobService(IClientService clientService, INodeServices nodeServices)
    {
        _clientService = clientService;
        _nodeServices = nodeServices;
    }

    //Some task to execute
    public async Task SomeTask(Guid subject)
    {
        // Do some job here
        Client client = _clientService.FindUserBySubject(subject);
    }      
}

And in your projects Startup.cs you can add a dependency as normal

services.AddTransient< IClientService, ClientService>();

Not sure this answers your question or not

回答3:

DoritoBandito's answer is incomplete or deprecated.

public class EmailSender {
     public EmailSender(IDbContext dbContext, IEmailService emailService)
     {
         _dbContext = dbContext;
         _emailService = emailService;
     }
}

Register services:

services.AddTransient<IDbContext, TestDbContext>();
services.AddTransient<IEmailService, EmailService>();

Enqueue:

BackgroundJob.Enqueue<EmailSender>(x => x.Send(13, "Hello!"));

Source: http://docs.hangfire.io/en/latest/background-methods/passing-dependencies.html

回答4:

I had to start HangFire in main function. This is how I solved it:

public static void Main(string[] args)
    {
        var host = CreateWebHostBuilder(args).Build();
        using (var serviceScope = host.Services.CreateScope())
        {
            var services = serviceScope.ServiceProvider;

            try
            {
                var liveDataHelper = services.GetRequiredService<ILiveDataHelper>();
                var justInitHangfire = services.GetRequiredService<IBackgroundJobClient>();
                //This was causing an exception (HangFire is not initialized)
                RecurringJob.AddOrUpdate(() => liveDataHelper.RePopulateAllConfigDataAsync(), Cron.Daily());
                // Use the context here
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "Can't start " + nameof(LiveDataHelper));
            }
        }
        host.Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseStartup<Startup>();
}

回答5:

Currently, Hangfire is deeply integrated with Asp.Net Core. Install Hangfire.AspNetCore to set up the dashboard and DI integration automatically. Then, you just need to define your dependencies using ASP.NET core as always.