将自定义类注入AuthorizationHandler时发生异常

Question

I have a custom policy to check some authorization.

Startup.cs:

public void ConfigureServices(IServiceCollection services)
{
    services.AddTransient<IPermissionsManager, PermissionsManager>();

    services.AddAuthorization(options =>
    {
        options.AddPolicy("HasPermission",
            policy => policy.Requirements.Add(new CheckProjectAccessLevelRequirement()));
    });

    services.AddSingleton<IAuthorizationHandler, CheckProjectAccessLevelHandler>();
}

Inside the CheckProjectAccessLevelHandler I want to make use of the PermissionsManager.

public class CheckProjectAccessLevelHandler : AuthorizationHandler<CheckProjectAccessLevelRequirement>
{
    readonly AuthHandlersContext _dbAuthContext;
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly PermissionsManager _permissionsManager;

    public CheckProjectAccessLevelHandler(AuthHandlersContext context, UserManager<ApplicationUser> userManager, PermissionsManager permissionsManager)
    {
        _dbAuthContext = context;
        _userManager = userManager;
        _permissionsManager = permissionsManager;
    }

    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, CheckProjectAccessLevelRequirement requirement)
    {
        _permissionsManager.doStuff()
    }
}

But I get this exception:

System.InvalidOperationException: Unable to resolve service for type 'myProject.Services.PermissionsManager' while attempting to activate 'myProject.Services.AuthHandlers.CheckProjectAccessLevelHandler'.

Without the injection of the PermissionsManager everything works as expected.

What do I miss?

Answer 1

You registered IPermissionManager (with services.AddTransient<IPermissionsManager, PermissionsManager>(); ) to be resolvable, so you should change ctor parameter to IPermissionsManager too:

public CheckProjectAccessLevelHandler(
    AuthHandlersContext context, 
    UserManager<ApplicationUser> userManager, 
    IPermissionsManager permissionsManager) // <-- here
{
    ...