Strathweb.TypedRouting.AspNetCore

A library enabling strongly typed routing in ASP.NET Core MVC projects.

Installation

Everything is on Nuget.

nuget install Strathweb.TypedRouting.AspNetCore

or via the .NET Core CLI:

dotnet add package Strathweb.TypedRouting.AspNetCore

Setup

In your Startup class, after adding MVC, call AddTypedRouting(); and then configure your routes:

services.AddMvc().AddTypedRouting(opt =>
{
    opt.Get("homepage", c => c.Action<HomeController>(x => x.Index()));
    opt.Get("aboutpage/{name}", c => c.Action<HomeController>(x => x.About(Param<string>.Any)));
    opt.Post("sendcontact", c => c.Action<HomeController>(x => x.Contact()));
});

This creates:

• a GET route to /homepage
• a GET route to /aboutpage/{name}
• a POST route to /sendcontact

All of which will route to the relevant methods on our HomeController.

Link generation

Since the API is fluent, you can also give the routes names so that you can use them with i.e. link generation.

opt.Get("api/values/{id}", c => c.Action<ValuesController>(x => x.Get(Param<int>.Any))).WithName("GetValueById");

Now you can use it with IUrlHelper (it's a Url property on every controller):

var link = Url.Link("GetValueById", new { id = 1 });

IUrlHelper can also be obtained from HttpContext, anywhere in the pipeline (i.e. in a filter):

var services = context.HttpContext.RequestServices;
var urlHelper = services.GetRequiredService<IUrlHelperFactory>().GetUrlHelper(context);
var link = urlHelper.Link("GetValueById", new { id = 1 });

Finally, you can also use this link generation technique with the built-in action results, such as for example CreatedAtRouteResult:

public IActionResult Post([FromBody]string value)
{
    var result = CreatedAtRoute("GetValueById", new { id = 1 }, "foo");
    return result;
}

Filters

The route definitions can also be done along with filters that should be executed for a given route. This is equivalent to defining a controller action, and annotating it with a relevant attribute such as action filter or authorization filter.

services.AddMvc().AddTypedRouting(opt =>
{
    opt.Get("api/items", c => c.Action<ItemsController>(x => x.Get())).WithFilters(new AnnotationFilter());
});

Filters can also be resolved from ASP.NET Core DI system - as long as they are registered there before.

services.AddSingleton<TimerFilter>();

services.AddMvc().AddTypedRouting(opt =>
{
    opt.Get("api/items", c => c.Action<ItemsController>(x => x.Get())).WithFilter<TimerFilter>();
});

Authorization Policies

The route definitions can also have ASP.NET Core authorization policies attached to them.

You can pass in a policy instance:

services.AddMvc().AddTypedRouting(opt =>
{
        opt.Get("api/secure", c => c.Action<OtherController>(x => x.Foo()).
                WithAuthorizationPolicy(new AuthorizationPolicyBuilder().RequireAuthenticatedUser().Build()));
});

You can also define a policy as string - then a corresponding policy must be previously registerd in ASP.NET Core DI system.

services.AddAuthorization(o =>
{
        o.AddPolicy("MyPolicy", b => b.RequireAuthenticatedUser());
});

services.AddMvc().AddTypedRouting(opt =>
{
        opt.Get("api/secure", c => c.Action<OtherController>(x => x.Foo()).
                WithAuthorizationPolicy("MyPolicy"));
});

Action constraints

The library supports two ways of specifying MVC action constraints:

• inline in the template
• via fluent API

The inline constraints are the same as you can use with attribute routing. For example:

opt.Get("api/other/{id:int}", c => c.Action<OtherController>(x => x.Action2(Param<int>.Any)));

You can also specify constraints via the fluent API, by chaining IActionConstraintMetadata implementations. Consider the following sample constraint class:

    public class MandatoryHeaderConstraint : IActionConstraint, IActionConstraintMetadata
    {
        private string _header;

        public MandatoryHeaderConstraint(string header)
        {
            _header = header;
        }

        public int Order
        {
            get
            {
                return 0;
            }
        }

        public bool Accept(ActionConstraintContext context)
        {
            // only allow route to be hit if the predefined header is present
            if (context.RouteContext.HttpContext.Request.Headers.ContainsKey(_header))
            {
                return true;
            }

            return false;
        }
    }

You can now use this class in the route declaration:

opt.Get("api/other", c => c.Action<OtherController>(x => x.Action1())).WithConstraints(new MandatoryHeaderConstraint("CustomHeader"));

License

MIT