public class WebApiControllerSelector : 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 WebApiControllerSelector(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.ToLower());
// 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;
}
// 取路由相应值
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);
}
//匹配相应路由
public HttpControllerDescriptor SelectController(HttpRequestMessage request)
{
IHttpRouteData routeData = request.GetRouteData();
if (routeData == null)
{
throw new HttpResponseException(HttpStatusCode.NotFound);
}
//从Route中读取命名空间名称和控制器名称
string controllerName = GetRouteVariable<string>(routeData, ControllerKey).ToLower();
if (controllerName == null)
{
throw new HttpResponseException(HttpStatusCode.NotFound);
}
HttpControllerDescriptor controllerDescriptor;
//获取版本号
var version = GetVersionFromAcceptHeaderVersion(request);
var versionedControllerName = string.Concat(controllerName, version).ToLower();
string versionkey = versionedControllerName;
//寻找匹配项
HttpControllerDescriptor versionedControllerDescriptor;
//如果命名空间名称为空，调用BaseRoute，反之采用DefaultApi
string namespaceName = GetRouteVariable<string>(routeData, NamespaceKey);
string key = controllerName;
if (namespaceName != null)
{
key = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", namespaceName, controllerName);
versionkey = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", namespaceName, versionedControllerName);
if (_controllers.Value.TryGetValue(key, out controllerDescriptor))
{
if (_controllers.Value.TryGetValue(versionkey, out versionedControllerDescriptor))
{
return versionedControllerDescriptor;
}
return controllerDescriptor;
}
else if (_duplicates.Contains(key))
{
throw new HttpResponseException(
request.CreateErrorResponse(HttpStatusCode.InternalServerError,
"该请求有多个控制器匹配，请检查路由配置"));
}
else
{
throw new HttpResponseException(HttpStatusCode.NotFound);
}
}
else
{
var basecontroller = _controllers.Value.Where(p => p.Key.ToLower().EndsWith(key));
if (basecontroller.Any())
{
if (basecontroller.Count() > 1)
{
throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.InternalServerError,"该请求有多个控制器匹配，请检查路由配置"));
}
controllerDescriptor = basecontroller.FirstOrDefault().Value;
var baseVersioncontroller = _controllers.Value.Where(p => p.Key.ToLower().EndsWith(versionkey));
if (baseVersioncontroller.Any())
{
return baseVersioncontroller.FirstOrDefault().Value;
}
return controllerDescriptor;
}
else
{
throw new HttpResponseException(HttpStatusCode.NotFound);
}
}
}
public IDictionary<string, HttpControllerDescriptor> GetControllerMapping()
{
return _controllers.Value;
}
/// <summary>
/// 添加版本控制
/// </summary>
/// <param name="request"></param>
/// <returns></returns>
private string GetVersionFromAcceptHeaderVersion(HttpRequestMessage request)
{
var acceptHeader = request.Headers.Accept;
if (acceptHeader.Any())
{
var format = acceptHeader.First();
format.MediaType = JsonMediaTypeFormatter.DefaultMediaType.MediaType;
}
var heads = HttpContext.Current.Request.Headers;
if (heads.AllKeys.Contains("Version"))
{
return heads.GetValues("Version").FirstOrDefault();
}
return "1";
}
}
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{namespace}/{id}/{controller}/{subid}/{action}",
defaults: new { subid = RouteParameter.Optional, action = RouteParameter.Optional }
);
config.Routes.MapHttpRoute(
name: "AllApi",
routeTemplate: "api/{namespace}/{controller}",
defaults: new { }
);
config.Services.Replace(typeof(IHttpControllerSelector), new WebApiControllerSelector(config));
