Is there a better way than using an IAsyncActionFilter to authorize if user is in role or user id is in database for specific record

问题

Requirement: There are some controller methods which only can be called if:

1. User has role "TaskAdmin"

OR

2. User is responsible for the database object which will be modified within the controller method (There is just a column with an user id to compare). The records in this datatable can change and are not "hardcoded".

I know 2 possibilities to solve this problem:

1. Create 2 methods. One with the attribute [Authorize(Roles = "TaskAdmin")] and one where it will be checked if the user is responsible for the database object.

2. Create an IAsyncActionFilter which checks both requirements and a TypeFilterAttribute to use on the controller methods.

Is there a better way to do this (with ASP.NET Core)?

回答1:

Is there a better way to do this (with ASP.NET Core)?

Yes. You can use Policy Based Authorization to implement complex permission-based rules.

public class RecordOwnerRequirement : IAuthorizationRequirement
{
}

public class RecordOwnerHandler : AuthorizationHandler<RecordOwnerRequirement>
{
    private readonly ApplicationDbContext dbContext;
    private readonly IActionContextAccessor actionContextAccessor;

    public RecordOwnerHandler(ApplicationDbContext dbContext, IActionContextAccessor actionContextAccessor)
    {
        this.dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
        this.actionContextAccessor = actionContextAccessor ?? throw new ArgumentNullException(nameof(actionContextAccessor));
    }

    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, RecordOwnerRequirement requirement)
    {
        if (IsUserAuthorized(context))
        {
            context.Succeed(requirement);
        }

        //TODO: Use the following if targeting a version of
        //.NET Framework older than 4.6:
        //      return Task.FromResult(0);
        return Task.CompletedTask;
    }

    private bool IsUserAuthorized(AuthorizationHandlerContext context)
    {
        var id = this.actionContextAccessor.ActionContext.RouteData.Values["id"];

        // Use the dbContext to compare the id against the database...

        // Return the result
        return true;
    }
}

Startup.cs

// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    services.AddIdentity<ApplicationUser, IdentityRole>()
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

    //*********************************************************************
    // Add policy for record owner 
    services.AddAuthorization(options =>
    {
        options.AddPolicy("RecordOwner", policy =>
            policy.Requirements.Add(new RecordOwnerRequirement()));
    });
    //*********************************************************************

    // Add application services.
    services.AddTransient<IEmailSender, EmailSender>();

    //*********************************************************************
    // Register record owner handler with the DI container 
    services.AddTransient<IAuthorizationHandler, RecordOwnerHandler>();
    services.AddTransient<IActionContextAccessor, ActionContextAccessor>();
    //*********************************************************************

    services.AddMvc();
}

Usage

public class HomeController : Controller
{
    [Authorize(Roles = "TaskAdmin", Policy = "RecordOwner")]
    public IActionResult Contact()
    {
        ViewData["Message"] = "Your contact page.";

        return View();
    }
}

来源：https://stackoverflow.com/questions/48785287/is-there-a-better-way-than-using-an-iasyncactionfilter-to-authorize-if-user-is-i