The constraint entry 'inboundHttpMethod' must have a string value or be of a type which implements 'IHttpRouteConstraint

Question

I am trying to implement attribute routing, but getting following error.

The constraint entry 'inboundHttpMethod' on the route with route template 'authenticate' must have a string value or be of a type which implements 'IHttpRouteConstraint

I already added the line of code in Global.asax,

    AttributeRoutingHttpConfig.RegisterRoutes(GlobalConfiguration.Configuration.Routes);

and the below code in AttributeRoutingHttpConfig.cs,

routes.MapHttpAttributeRoutes(cfig =>
            {
                cfig.UseLowercaseRoutes = true;
                cfig.AutoGenerateRouteNames = true;
                cfig.AddRoutesFromAssemblyOf<AuthenticateController>();
                cfig.InMemory = true;
            });

Anyone know about the issue, actually I am new to c#.

Answer 1

You are using the wrong packages.

From what I can see you are trying to implement attribute routing using this NuGet package (old and no longer supported).

This package supports Web API v1 (assembly version 4.*), and not Web API 2 (assembly version 5.*).

Web API 2 support for attribute routing is native. This tutorial may help you implementing such a feature: Attribute Routing in Web API 2

Here it is a small example:

[RoutePrefix("v1/myexample")]
public MyController : ApiController {
    [Route("foo")]
    public string GetFoo()
    {
        return "foo";
    }
}

This action may be reached at the following endpoint: http://myhost/v1/myexample/foo.

Remember to register them in your WebApiConfig.cs file:

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.MapHttpAttributeRoutes();

        // Other Web API configuration
    }
}