在 ASP.NET Web API 中，使用 命名空间（namespace） 来作为路由的参数

public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
config.MapHttpAttributeRoutes(); config.Services.Replace(typeof(IHttpControllerSelector), new NamespaceHttpControllerSelector(config)); config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "{namespace}/{controller}/{action}"
);
}
}

public class NamespaceHttpControllerSelector : IHttpControllerSelector
{
private const string NamespaceKey = "namespace";
private const string ControllerKey = "controller"; private readonly HttpConfiguration _configuration;
private readonly Lazy<Dictionary<string, HttpControllerDescriptor>> _controllers;
private readonly HashSet<string> _duplicates; public NamespaceHttpControllerSelector(HttpConfiguration config)
{
_configuration = config;
_duplicates = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
_controllers = new Lazy<Dictionary<string, HttpControllerDescriptor>>(InitializeControllerDictionary);
} private Dictionary<string, HttpControllerDescriptor> InitializeControllerDictionary()
{
var dictionary = new Dictionary<string, HttpControllerDescriptor>(StringComparer.OrdinalIgnoreCase); // Create a lookup table where key is "namespace.controller". The value of "namespace" is the last
// segment of the full namespace. For example:
// MyApplication.Controllers.V1.ProductsController => "V1.Products"
IAssembliesResolver assembliesResolver = _configuration.Services.GetAssembliesResolver();
IHttpControllerTypeResolver controllersResolver = _configuration.Services.GetHttpControllerTypeResolver(); ICollection<Type> controllerTypes = controllersResolver.GetControllerTypes(assembliesResolver); foreach (Type t in controllerTypes)
{
var segments = t.Namespace.Split(Type.Delimiter); // For the dictionary key, strip "Controller" from the end of the type name.
// This matches the behavior of DefaultHttpControllerSelector.
var controllerName = t.Name.Remove(t.Name.Length - DefaultHttpControllerSelector.ControllerSuffix.Length); var key = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", segments[segments.Length - 1], controllerName); // Check for duplicate keys.
if (dictionary.Keys.Contains(key))
{
_duplicates.Add(key);
}
else
{
dictionary[key] = new HttpControllerDescriptor(_configuration, t.Name, t);
}
} // Remove any duplicates from the dictionary, because these create ambiguous matches.
// For example, "Foo.V1.ProductsController" and "Bar.V1.ProductsController" both map to "v1.products".
foreach (string s in _duplicates)
{
dictionary.Remove(s);
}
return dictionary;
} // Get a value from the route data, if present.
private static T GetRouteVariable<T>(IHttpRouteData routeData, string name)
{
object result = null;
if (routeData.Values.TryGetValue(name, out result))
{
return (T)result;
}
return default(T);
} public HttpControllerDescriptor SelectController(HttpRequestMessage request)
{
IHttpRouteData routeData = request.GetRouteData();
if (routeData == null)
{
throw new HttpResponseException(HttpStatusCode.NotFound);
} // Get the namespace and controller variables from the route data.
string namespaceName = GetRouteVariable<string>(routeData, NamespaceKey);
if (namespaceName == null)
{
throw new HttpResponseException(HttpStatusCode.NotFound);
} string controllerName = GetRouteVariable<string>(routeData, ControllerKey);
if (controllerName == null)
{
throw new HttpResponseException(HttpStatusCode.NotFound);
} // Find a matching controller.
string key = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", namespaceName, controllerName); HttpControllerDescriptor controllerDescriptor;
if (_controllers.Value.TryGetValue(key, out controllerDescriptor))
{
return controllerDescriptor;
}
else if (_duplicates.Contains(key))
{
throw new HttpResponseException(
request.CreateErrorResponse(HttpStatusCode.InternalServerError,
"Multiple controllers were found that match this request."));
}
else
{
throw new HttpResponseException(HttpStatusCode.NotFound);
}
} public IDictionary<string, HttpControllerDescriptor> GetControllerMapping()
{
return _controllers.Value;
}
}