c# – 使用媒体类型版本化ASP.NET Web API 2

我收到以下错误：

The given key was not present in the dictionary.

它来源于FindActionMatchRequiredRouteAndQueryParameters()方法中的关键_actionParameterNames [descriptor].

foreach (var candidate in candidatesFound)
{
        HttpActionDescriptor descriptor = candidate.ActionDescriptor;
        if (IsSubset(_actionParameterNames[descriptor],candidate.CombinedParameterNames))
        {
            matches.Add(candidate);
        }
}

资料来源：ApiControllerActionSelector.cs

进一步调试后,我意识到如果你有两个控制器

[RoutePrefix("api/people")]
public class PeopleController : BaseApiController
{
    [Route("")]
    public HttpResponseMessage GetPeople()
    {
    }

    [Route("identifier/{id}")]
    public HttpResponseMessage GetPersonById()
    {
    }
}

[RoutePrefix("api/people")]
public class PeopleV2Controller : BaseApiController
{     
    [Route("")]
    public HttpResponseMessage GetPeople()
    {
    } 

    [Route("identifier/{id}")]
    public HttpResponseMessage GetPersonById()
    {
    }
}

您不能使用您的自定义ApiVersioningSelector : DefaultHttpControllerSelector,因为它将测试所有键,如上所述,具有相同[RoutePrefix(“api / people”)]的所有控制器,显然会抛出异常.

只是为了确保选择了正确的控制器

我不知道这是否是一个错误,但是使用路由[RoutePrefix(“api / v1 / people”)]到版本API让我很伤心.

注意：没有属性路由,这很有效.

UPDATE

public class ApiVersioningSelector : DefaultHttpControllerSelector
    {
        private HttpConfiguration _HttpConfiguration;
        public ApiVersioningSelector(HttpConfiguration httpConfiguration)
            : base(httpConfiguration)
        {
            _HttpConfiguration = httpConfiguration;
        }



        public override HttpControllerDescriptor SelectController(HttpRequestMessage request)
        {
            IDictionary<string,HttpControllerDescriptor> controllers = GetControllerMapping();                                             

            var attributedRoutesData = request.GetRouteData().GetSubRoutes();
            var subRouteData = attributedRoutesData.LastOrDefault(); //LastOrDefault() will get PeopleController,FirstOrDefault will get People{version}Controller which we don't want

            var actions = (ReflectedHttpActionDescriptor[])subRouteData.Route.DataTokens["actions"];
            var controllerName = actions[0].ControllerDescriptor.ControllerName;


            //For controller name without attribute routing
            //var controllerName = (string)routeData.Values["controller"];

            HttpControllerDescriptor oldControllerDescriptor;
            if (controllers.TryGetValue(controllerName,out oldControllerDescriptor))
            {
                var apiVersion = GetVersionFromMediaType(request);

                var newControllerName = String.Concat(controllerName,"V",apiVersion);

                HttpControllerDescriptor newControllerDescriptor;
                if (controllers.TryGetValue(newControllerName,out newControllerDescriptor))
                {
                    return newControllerDescriptor;
                }
                return oldControllerDescriptor;
            }
            return null;
        }


        private string GetVersionFromMediaType(HttpRequestMessage request)
        {
            var acceptHeader = request.Headers.Accept;

            var regularExpression = new Regex(@"application/vnd.mycompany.([a-z]+).v([0-9]+)+json",RegexOptions.IgnoreCase);

            foreach (var mime in acceptHeader)
            {
                var match = regularExpression.Match(mime.MediaType);
                if (match != null)
                {
                    return match.Groups[2].Value;
                }
            }
            return "1";
        }

    }