accessing dbcontext within an Authroization Policy Requirement Handler

Question

in a previous posting from a few years ago - Can Policy Based Authorization be more dynamic?

one of the answers offers up the following code:

Then define the handler.

public class MinimumAgeHandler : AuthorizationHandler<DataDrivenRequirement>
{
    protected override void Handle(AuthorizationContext context, 
                                   DataDrivenRequirement requirement)
    {
        // Do anything here, **interact with DB**, User, claims, Roles, etc.
        // As long as you set either:
        //    context.Succeed(requirement);
        //    context.Fail();
    }
}

I am using .NET Core 3 MVC with EntityFrameworkCore. I wish to interact with a database in the Handler. The Handler is not passed a dbcontext like a Controller is. I have tried several ways to do it without any success. Does anyone know how to access a dbcontext from here?

Just so you know, the closest I came was using the following code from another post - How to access dbcontext & session in Custom Policy-Based Authorization

public class CheckAuthorizeHandler : AuthorizationHandler<CheckAuthorizeRequirement>
{
    MyContext _context;

    public CheckAuthorizeHandler(MyContext context)
    {
        _context = context;
    }

    protected override Task HandleRequirementAsync(
        AuthorizationHandlerContext context, 
        MyRequirement requirement)
    {
        // Do something with _context
        // Check if the requirement is fulfilled.
        return Task.CompletedTask;
    }
}

but got the following error: InvalidOperationException: Cannot consume scoped service 'NASAppsAdmin.Models.NASAppsDbContext' from singleton 'Microsoft.AspNetCore.Authorization.IAuthorizationHandler'.

`InvalidOperationException: Cannot consume scoped service 'NASAppsAdmin.Models.NASAppsDbContext' from singleton 'Microsoft.AspNetCore.Authorization.IAuthorizationHandler'.` Entity Framework contexts are usually added to the service container using the scoped lifetime, if you'd like to use database context from your handler, plese make sure your handler is not registered as singleton. — Fei Han, Feb 03 '20 at 06:29

score 1 · Accepted Answer · answered Feb 04 '20 at 13:07

InvalidOperationException: Cannot consume scoped service 'NASAppsAdmin.Models.NASAppsDbContext' from singleton 'Microsoft.AspNetCore.Authorization.IAuthorizationHandler'. Entity Framework contexts are usually added to the service container using the scoped lifetime, if you'd like to use database context from your handler, plese make sure your handler is not registered as singleton. – Fei Han

accessing dbcontext within an Authroization Policy Requirement Handler

1 Answers1