如何在ASP.NET Core中为多角色配置多条独立默认路由？

方案1：自定义路由约束实现多角色默认路由 #

步骤1：创建角色路由约束类 #

public class RoleRouteConstraint : IRouteConstraint
{
    private readonly string _requiredRole;

    public RoleRouteConstraint(string requiredRole)
    {
        _requiredRole = requiredRole;
    }

    public bool Match(HttpContext? httpContext, IRouter? route, string routeKey, RouteValueDictionary values, RouteDirection routeDirection)
    {
        if (httpContext == null || !httpContext.User.Identity.IsAuthenticated)
            return false;
        return httpContext.User.IsInRole(_requiredRole);
    }
}

步骤2：注册路由约束 #

在Startup.cs的ConfigureServices方法中添加注册：

services.AddRouting(options =>
{
    options.ConstraintMap.Add("requiresRole", typeof(RoleRouteConstraint));
});

步骤3：配置多角色默认路由 #

在UseEndpoints中按优先级注册路由（优先级高的规则放前面）：

app.UseEndpoints(endpoints =>
{
    // Admin角色默认路由：匹配Admin角色用户访问根路径的场景
    endpoints.MapControllerRoute(
        name: "adminDefault",
        pattern: "{controller=AdminDashboard}/{action=Index}/{id?}",
        constraints: new { requiresRole = "Admin" })
        .RequireAuthorization("Admin");

    // User角色默认路由：匹配User角色用户访问根路径的场景
    endpoints.MapControllerRoute(
        name: "userDefault",
        pattern: "{controller=UserCenter}/{action=Home}/{id?}",
        constraints: new { requiresRole = "User" })
        .RequireAuthorization("User");

    // 未匹配到角色的兜底路由，可指向登录页或公共首页
    endpoints.MapControllerRoute(
        name: "fallback",
        pattern: "{controller=Account}/{action=Login}/{id?}");
});

方案2：轻量实现（默认控制器重定向） #

如果不想编写自定义约束，也可以直接在公共默认控制器的Action中做角色判断跳转，代码更简洁：

public class HomeController : Controller
{
    public IActionResult Index()
    {
        if (User.IsInRole("Admin"))
        {
            return RedirectToAction("Index", "AdminDashboard");
        }
        if (User.IsInRole("User"))
        {
            return RedirectToAction("Home", "UserCenter");
        }
        return RedirectToAction("Login", "Account");
    }
}

对应的路由配置只需要保留默认路由指向Home/Index即可：

app.UseEndpoints(endpoints =>
{
    endpoints.MapControllerRoute(
        name: "default",
        pattern: "{controller=Home}/{action=Index}/{id?}")
        .RequireAuthorization();
});

内容的提问来源于stack exchange，提问作者masoud