使用媒体类型对 ASP.NET Web API 2 进行版本控制 [英] Versioning ASP.NET Web API 2 with Media Types

问题描述

我正在使用带有属性路由的 ASP.NET Web API 2，但我似乎无法使用媒体类型进行版本控制 application/vnd.company[.version].param[+json] 上班.

I'm using ASP.NET Web API 2 with attribute routing but i can't seem to get the versioning using media types application/vnd.company[.version].param[+json] to work.

我收到以下错误:

字典中不存在给定的键.

The given key was not present in the dictionary.

源于测试 FindActionMatchRequiredRouteAndQueryParameters() 方法中的关键 _actionParameterNames[descriptor].

which originates from testing the key _actionParameterNames[descriptor] in FindActionMatchRequiredRouteAndQueryParameters() method.

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

来源:ApiControllerActionSelector.cs

进一步调试后我意识到如果你有两个控制器

After further debugging I've realized that if you have two controllers

[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()
    {
    }
}

你不能使用你的自定义ApiVersioningSelector: DefaultHttpControllerSelector 因为它将测试密钥，如上所述，来自所有具有相同 [RoutePrefix("api/people")] 的控制器，显然一个例外是抛出.

you can't use your custom ApiVersioningSelector : DefaultHttpControllerSelector because it will test the keys,as stated above, from all controllers having the same [RoutePrefix("api/people")] and obviously an exception will be thrown.

只是为了确保选择了正确的控制器

Just to be sure the right controller was selected

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

I don't know if this is a bug, but using route [RoutePrefix("api/v1/people")] to version API makes me sad.

注意:这在没有属性路由的情况下效果很好.

NOTE: This works great without attribute routing.

更新

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";
        }

    }

推荐答案

感谢您分享您的代码.我已经修改了您的版本控制器选择器，如下所示，并尝试了一些场景，它似乎运行良好.您可以尝试像下面这样更新您的控制器选择器，看看它是否有效吗?

Thanks for the sharing your code. I have modified your version controller selector like below and tried some scenarios and it seems to work well. Can you try updating your controller selector like below and see if it works?

    public override HttpControllerDescriptor SelectController(HttpRequestMessage request)
    {
        HttpControllerDescriptor controllerDescriptor = null;

        // get list of all controllers provided by the default selector
        IDictionary<string, HttpControllerDescriptor> controllers = GetControllerMapping();

        IHttpRouteData routeData = request.GetRouteData();

        if (routeData == null)
        {
            throw new HttpResponseException(HttpStatusCode.NotFound);
        }

        //check if this route is actually an attribute route
        IEnumerable<IHttpRouteData> attributeSubRoutes = routeData.GetSubRoutes();

        var apiVersion = GetVersionFromMediaType(request);

        if (attributeSubRoutes == null)
        {
            string controllerName = GetRouteVariable<string>(routeData, "controller");
            if (controllerName == null)
            {
                throw new HttpResponseException(HttpStatusCode.NotFound);
            }

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

            if (controllers.TryGetValue(newControllerName, out controllerDescriptor))
            {
                return controllerDescriptor;
            }
            else
            {
                throw new HttpResponseException(HttpStatusCode.NotFound);
            }
        }
        else
        {
            // we want to find all controller descriptors whose controller type names end with
            // the following suffix(ex: CustomersV1)
            string newControllerNameSuffix = String.Concat("V", apiVersion);

            IEnumerable<IHttpRouteData> filteredSubRoutes = attributeSubRoutes.Where(attrRouteData =>
            {
                HttpControllerDescriptor currentDescriptor = GetControllerDescriptor(attrRouteData);

                bool match = currentDescriptor.ControllerName.EndsWith(newControllerNameSuffix);

                if (match && (controllerDescriptor == null))
                {
                    controllerDescriptor = currentDescriptor;
                }

                return match;
            });

            routeData.Values["MS_SubRoutes"] = filteredSubRoutes.ToArray();
        }

        return controllerDescriptor;
    }

    private HttpControllerDescriptor GetControllerDescriptor(IHttpRouteData routeData)
    {
        return ((HttpActionDescriptor[])routeData.Route.DataTokens["actions"]).First().ControllerDescriptor;
    }

    // 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);
    }

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