Feature request: Ability to configure IBlazorDownloadFileService lifetime

[Anil86]

I need a singleton instance of BlazorDownloadFileService (internal class).

Please allow configuring registering IBlazorDownloadFileService.

Expected api:

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddBlazorDownloadFile(Microsoft.Extensions.DependencyInjection.ServiceLifetime lifetime);
    }
}

---

---

EF.Core allows configuring DbContext lifetime.

public static IServiceCollection Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.AddDbContext<TContext>(
    [NotNull] this IServiceCollection serviceCollection,
    [CanBeNull] Action<DbContextOptionsBuilder> optionsAction = null,
    ServiceLifetime contextLifetime = ServiceLifetime.Scoped,
    ServiceLifetime optionsLifetime = ServiceLifetime.Scoped)

[arivera12]

I will take a look on how to implement this when I have some free time. You can fork and make pull request if you want to contribute.

[arivera12]

I took a look on the web and looks easy to implement.

[arivera12]

Install-Package BlazorDownloadFile -Version 2.1.2

[Anil86]

The new api allows specifying IBlazorDownloadFileService lifetime.
I'm getting following error:

System.InvalidOperationException: Cannot resolve scoped service 'Microsoft.JSInterop.IJSRuntime' from root provider.
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteValidator.ValidateResolution(Type serviceType, IServiceScope scope, IServiceScope rootScope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.Microsoft.Extensions.DependencyInjection.ServiceLookup.IServiceProviderEngineCallback.OnResolve(Type serviceType, IServiceScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
...
...

Probably Microsoft.JSInterop.IJSRuntime must be registered as singleton.

[arivera12]

I never test changing the lifetime of the service.

Now that I remember, initially I tried setting BlazorDownloadFileService as a singleton by default and I crash into this error.

There was a explanation for this and is when you declare a Singleton service it forces to initialize at that instance, when service collection are initializing IJSRuntime is not available from the service provider.

In general explanation: if you are setting up a service than depends on another service the Singleton will trow this exception always

When you use Scoped or Transient the instance gets initialize when you use it (Inject), that's the reason why Singleton won't work on this case unless we expose the JSRuntime property and you set it after WebAssemblyHost host = builder.Build();.

But doing this I don't think it's a good idea.

It may broke the Service at any time.

I don't think there is not anything else I can do here.

Why are you needing BlazorDownloadFileService as a Singleton.

[Anil86]

I think what you are saying is that singleton services are immediately initialized while their dependencies may not have been initialized yet.

---

Why are you needing BlazorDownloadFileService as a Singleton?

I'm queueing jobs using Hangfire.
Method to add a job: BackgroundJob.Enqueue<Service>(Job).
Hangfire instantiates new Service for every job added.
I was trying to register Service as a Singleton so that all the jobs can share same Service property value.

[arivera12]

I can recommend you 2 options:

1. Make BlazorDownloadFileService a Transient service and try again.
2. Move BlazorDownloadFileService into a global scope in your context and past it down to your function globally and try again.

Let me know if any of those options worked for you.

If not let me know so I will add the modifications to make BlazorDownloadFileService available as a Singleton.

[Anil86]

1. Making BlazorDownloadFileService a Transient service didn't work
2. Storing BlazorDownloadFileService as a static variable in Startup.cs worked partially.

Still got the error:

System.InvalidOperationException: JavaScript interop calls cannot be issued at this time. This is because the component is being statically rendererd. When prerendering is enabled, JavaScript interop calls can only be performed during the OnAfterRenderAsync lifecycle method.

I'm thinking of a simpler approach to have a single Job which will call dependent Service methods.
Thus Service doesn't need to be a Singleton.

[arivera12]

System.InvalidOperationException: JavaScript interop calls cannot be issued at this time. This is because the component is being statically rendererd. When prerendering is enabled, JavaScript interop calls can only be performed during the OnAfterRenderAsync lifecycle method.

Try using OnAfterRenderAsync instead of OnInitializedAsync.

The IJSRuntime is not available OnInitializedAsync lifetime.