I am using MVC 5 with autofac and in my my controller I call an action method that calls a method with ref parameter. When i try to browse to browse to the action method I get the below error that suggest that I can not use ref parameters. Is that correct?
Cannot call action method
'AllThings.WebUI.Models.SearchCriteriaViewModel
SetListData(System.String,
AllThings.WebUI.Models.SearchCriteriaViewModel ByRef,
AllThings.Entities.Abstracts.ISimpleService, Double)' on controller
'AllThings.WebUI.Controllers.PostController' because the parameter
'AllThings.WebUI.Models.SearchCriteriaViewModel&
searchCriteriaViewModel' is passed by reference. Parameter name:
methodInfo
cut down the code and the main code looks like this:
[Route("~/{site}/{CategoryUrl?}")]
[Route("~/{country:maxlength(2)}/{site}/{CategoryUrl?}", Name="ResultList")]
[AllowAnonymous]
public ActionResult List(string country, string site, SearchCriteriaViewModel searchCriteriaViewModel)
{
SetListData(site, ref searchCriteriaViewModel, simpleService, CommonLibrary.Helpers.GetCountryTimeZoneOffSet(countryIso2));
return View("List", searchCriteriaViewModel);
}
public SearchCriteriaViewModel SetListData(string site, ref SearchCriteriaViewModel searchCriteriaViewModel, ISimpleService simpleService, double utcOffset)
{
SearchCriteria searchCriteria = EntityFactory.GetSearchCriteria();
if (searchCriteriaViewModel.Category == null)
{
searchCriteriaViewModel.Category = new Category();
}
return searchCriteriaViewModel;
}
my autofac config looks like this
public static void Initialize()
{
var builder = new ContainerBuilder();
DependencyResolver.SetResolver(new AutoFacDependencyResolver(RegisterServices(builder)));
}
private static IContainer RegisterServices(ContainerBuilder builder)
{
builder.RegisterAssemblyTypes(typeof(MvcApplication).Assembly);
//builder.RegisterType<AllThings.Entities.Concrete.ContextFactory>().As<IContextFactory>().SingleInstance();
builder.RegisterType<AllThings.Entities.Concrete.SimpleService>().As<ISimpleService>().InstancePerRequest();
builder.RegisterType<AllThings.Entities.Concrete.EFSimpleRepository>().As<ISimpleRepository>().InstancePerRequest();
//builder.RegisterInstance(GetMockContext()).As<IContextFactory>();
return builder.Build();
}
What do you expect the ref parameter to do? Your action method gets called using reflection, based on an incoming HTTP request. It's not like if you modify the ref parameter, the object on the client changes too - it's entirely disconnected through the nature of HTTP.
Just remove the ref modifier.
Related
I have a stateless service in Azure Service Fabric, and I'm using Microsoft.Extensions.DependencyInjection, although the same issue exists for any other DI frameworks. In my Program.cs, I create a ServiceCollection, add all (but one) of my registrations, create the service provider, and pass it to my service's constructor. Any service method with external entry will create a new service scope and call the main business logic class. The issue is that one of the classes I want to have scoped lifetime needs a value that is an input parameter on the request itself. Here's a code snippet of what I would like to achieve.
internal sealed class MyService : StatelessService, IMyService
{
private IServiceProvider _serviceProvider;
private IServiceScopeFactory _scopeFactory;
public MyService(StatelessServiceContext context, IServiceProvider serviceProvider)
: base(context)
{
_serviceProvider = serviceProvider;
_scopeFactory = _serviceProvider.GetRequiredService<IServiceScopeFactory>();
}
public async Task<MyResponse> ProcessAsync(MyRequest request, string correlationId, CancellationToken cancellationToken)
{
using (var scope = _scopeFactory.CreateScope())
{
var requestContext = new RequestContext(correlationId);
//IServiceCollection serviceCollection = ??;
//serviceCollection.AddScoped<RequestContext>(di => requestContext);
var businessLogic = scope.ServiceProvider.GetRequiredService<BusinessLogic>();
return await businessLogic.ProcessAsync(request, cancellationToken);
}
}
}
The cancellation token is already passed around everywhere, including to classes that don't use it directly, just so it can be passed to dependencies that do use it, and I want to avoid doing the same with the request context.
The same issue exists in my MVC APIs. I can create middle-ware which will extract the correlation id from the HTTP headers, so the API controller doesn't need to deal with it like my service fabric service does. One way I can make it work is by giving RequestContext a default constructor, and have a mutable correlation id. However, it's absolutely critical that the correlation id doesn't get changed during a request, so I'd really like the safety of having get-only property on the context class.
My best idea at the moment is to have a scoped RequestContextFactory which has a SetCorrelationId method, and the RequestContext registration simply calls the factory to get an instance. The factory can throw an exception if a new instance is requested before the id is set, to ensure no id-less contexts are created, but it doesn't feel like a good solution.
How can I cleanly register read-only objects with a dependency injection framework, where the value depends on the incoming request?
I only had the idea for a RequestContextFactory as I was writing the original question, and I finally made time to test the idea out. It actually was less code than I expected, and worked well, so this will be my go-to solution now. But, the name factory is wrong. I'm not sure what to call it though.
First, define the context and factory classes. I even added some validation checks into the factory to ensure it worked the way I expect:
public class RequestContext
{
public RequestContext(string correlationId)
{
CorrelationId = correlationId;
}
public string CorrelationId { get; }
}
public class RequestContextFactory
{
private RequestContext _requestContext;
private bool _used = false;
public void SetContext(RequestContext requestContext)
{
if (_requestContext != null || requestContext == null)
{
throw new InvalidOperationException();
}
_requestContext = requestContext;
}
public RequestContext GetContext()
{
if (_used || _requestContext == null)
{
throw new InvalidOperationException();
}
_used = true;
return _requestContext;
}
}
Then, add registrations to your DI container:
services.AddScoped<RequestContextFactory>();
services.AddScoped<RequestContext>(di => di.GetRequiredService<RequestContextFactory>().GetContext());
Finally, the Service Fabric service method looks something like this
public async Task<MyResponse> ProcessAsync(MyRequest request, string correlationId, CancellationToken cancellationToken)
{
using (var scope = _scopeFactory.CreateScope())
{
var requestContext = new RequestContext(correlationId);
var requestContextFactory = scope.ServiceProvider.GetRequiredService<RequestContextFactory>();
requestContextFactory.SetContext(requestContext);
var businessLogic = scope.ServiceProvider.GetRequiredService<BusinessLogic>();
return await businessLogic.ProcessAsync(request, cancellationToken);
}
}
Kestrel middleware could look something like this
public async Task Invoke(HttpContext httpContext)
{
RequestContext requestContext = new RequestContext(Guid.NewGuid().ToString());
var factory = httpContext.RequestServices.GetRequiredService<RequestContextFactory>();
factory.SetContext(requestContext);
httpContext.Response.Headers["X-CorrelationId"] = requestContext.CorrelationId;
await _next(httpContext);
}
Then just do the normal thing and add a RequestContext parameter to the constructor of any class that needs to get the correlation id (or any other info you put in the request context)
I am new in unit test and MVC development.
I have a question for using moq for unit testing in asp.net mvc. I have a controller which accepts an ajax action:
[HttpPost,Authorize]
public ActionResult GrabLink()
{
string username = HttpContext.User.Identity.Name;
string rssUrl = Request.Params["Grablink"].ToString();
...}
This action deals with the http request which I generate from the view:
var mockRequest = new Moq.Mock<HttpRequestBase>();
but I can not find a way to define the parameters I used in the class. Also, is there any way to use the value binding provider directly to pass the value to the controller if I would like to do an ajax post?
I am a newbie in handling web request. If you have some good tutorial for better understanding the Http request (as well as the Httpcontext and related classes in asp.net) please post here. Thank you very much!
This works very well for me:
var controller = new HomeController();
var context = new Mock<HttpContextBase>(MockBehavior.Strict);
var controllerContext = new Mock<ControllerContext>();
controllerContext.SetupGet(x => x.HttpContext.User.Identity.Name)
.Returns("TestUser");
controllerContext.SetupGet(x => x.HttpContext.User.Identity.IsAuthenticated)
.Returns(true);
controllerContext.SetupGet(x => x.HttpContext.Request.IsAuthenticated)
.Returns(true);
controller.ControllerContext = controllerContext.Object;
// As a bonus, instantiate the Url helper to allow creating links
controller.Url = new UrlHelper(
new RequestContext(context.Object, new RouteData()), new RouteCollection());
This will allow you to initialize any user you want as an authenticated user, and the last line will allow you to user the Url helper within the controller even though you're calling it from a unit test.
As Scott said HttpContext makes Controllers hard to test. Anyway he's got a pretty solution at here.
BTW why didn't you make rssUrl a parameter if it is assigning by POST or GET?
e.g.
//POST: /GrabLink?rssUrl=bla bla...
[HttpPost,Authorize]
public ActionResult GrabLink(IPrincipal user, string rssUrl) {
string userName = user.Name;
}
Ok, #cem covered your second question very well.
For your first, nerddinner, and If I'm not mistaken, when you create a new Internet Application with Unit test, in Visual Studio, have the following mock classes for HttpContext. Its at the bottom of this file.
You could use these (or create a new Internet App +Tests with VS) and copy all the fake classes for your tests. (I wrote a Moq example below)
It looks like this:
public class MockHttpContext : HttpContextBase {
private IPrincipal _user;
public override IPrincipal User {
get {
if (_user == null) {
_user = new MockPrincipal();
}
return _user;
}
set {
_user = value;
}
}
public override HttpResponseBase Response
{
get
{
return new MockHttpResponse();
}
}
}
public class MockHttpResponse : HttpResponseBase {
public override HttpCookieCollection Cookies
{
get
{
return new HttpCookieCollection();
}
}
}
Not tested, but to Use mock it would look like this:
var fakeReqBase = new Mock<HttpRequestBase>();
fakeReqBase.Setup(f => f.User).Returns(new GenericIdentity("FakeUser"));
//generic identity implements IIdentity
fakeUserRepo.Object;//this returns fake object of type HttpRequestBase
Checkout the Moq Quickstart. Its quite easy to get used to, and the fluent interface really helps.
I'm try to build a static property on a static class that will basically return a cookie value, to be used across my MVC site (MVC 3, if it matters). Something like this:
public static class SharedData
{
public static string SomeValue
{
get
{
if (HttpContext.Current.Request.Cookies["SomeValue"] == null)
{
CreateNewSomeValue();
}
return HttpContext.Current.Request.Cookies["SomeValue"].Value.ToString();
}
}
}
I need to access this from within controller actions, global.asax methods, and action filters. But the problem is, when action filters run, HttpContext is not available. Right now, I have to have a separate static method just to pull the cookie from the filter context that I pass in, which seems awkward.
What is the best solution for building such a static method for retrieving a cookie value like this that works from both controller actions and action filters? Or is there a better approach for doing something like this?
Thanks in advance.
The call to the static HttpContext.Current is not good design. Instead, create an extension method to access the cookie from an instance of HttpContext and HttpContextBase.
I wrote a little helper for you. You can use it to perform your functionality from within an action filter.
public static class CookieHelper
{
private const string SomeValue = "SomeValue";
public static string get_SomeValue(this HttpContextBase httpContext)
{
if(httpContext.Request.Cookies[SomeValue]==null)
{
string value = CreateNewSomeValue();
httpContext.set_SomeValue(value);
return value;
}
return httpContext.Request.Cookies[SomeValue].Value;
}
public static void set_SomeValue(this HttpContextBase httpContext, string value)
{
var someValueCookie = new HttpCookie(SomeValue, value);
if (httpContext.Request.Cookies.AllKeys.Contains(SR.session))
{
httpContext.Response.Cookies.Set(someValueCookie);
}
else
{
httpContext.Response.Cookies.Add(someValueCookie);
}
}
}
Note: You could easily make these methods work on HttpContext instead just by replacing the HttpContextBase parameter with HttpContext.
As JohnnyO pointed out above, I had access to HttpContext from within my action filter all along. At least, in the particular action filter method where this was needed. There may have been some other filter/method that did not have access at one point, but for now, this is working as I need it to.
I'll start here with a little bit of background. We have an ASP.Net MVC web application that sits upon a structure roughly based upon the Onion Architecture concept. Therefore, we have the following (simplified) vertical structure:
ASP.Net MVC controller layer
Application service layer
Business Service layer
NOTE: The above is simplified because it doesn't deal with the views, repositories, domain objects, etc which aren't relevant to this question.
For a horizontal structure, we have some major areas defined by what we call "Item Types" (for the sake of simplicity, this question will deal with two sample item types: "ItemTypeA", "ItemTypeB", etc).
We have a business service interface which has a separate implementation per item type:
public interface ISampleBusinessService
{
string SampleMethod(string arg);
}
public class ItemTypeASampleBusinessService : ISampleBusinessService
{
public string SampleMethod(string arg)
{
return "Item Type A: " + arg;
}
}
public class ItemTypeBSampleBusinessService : ISampleBusinessService
{
public string SampleMethod(string arg)
{
return "Item Type B: " + arg;
}
}
Sitting above that is an application service that uses the business service:
public interface ISampleAppService
{
string SampleMethod(string arg);
}
public class SampleAppService
{
private readonly ISampleBusinessService service;
public SampleAppService(ISampleBusinessService service)
{
this.service = service
}
public string SampleMethod(string arg)
{
return service.SampleMethod(arg);
}
}
And sitting above that is our controller which uses the application service:
public class SampleController : Controller
{
private ISampelAppService service
public SampleController(ISampleAppService service)
{
this.service = service;
}
public PartialViewResult SampleAction(string arg)
{
return PartialView( service.SampleMethod(arg) );
}
}
Note that the controller, application service interface and implementation, and business service interface are all generic - they don't care about which item type is being used. However, the business service implementations are specific to the item type. We know which item type we're dealing with at the time we call the action method on the controller (via RenderAction in the views) but we aren't sure what the best way to determine which business service implementation to use. There are a few options we've considered:
Base class the controller and create item type-specific controller inheritors, then something similar with the app services. This feels like a weak solution - we would end up writing a few classes that add nothing in terms of functionality except to work out which item type we're dealing with.
Pass a flag down to the service layer and create the service implementation in a factory (i.e. a SampleBusinessServiceFactory which takes an "itemType" argument in its CreateInstance method). The problem with this is that we're passing a variable down several layers just so that we can decide upon an implementation. We have used this approach so far.
Generics - we haven't really thought this one through but it seems that there would be some difficulties with this as well (how would you call an Action method with generics from an ActionResult call in the view?). It would be similar, in a sense to passing a flag down, but would be based upon strongly typing object/services instead of using enums/magic strings.
What approach would be best suited to solving this problem? New options would be welcomed.
Any help provided will be much appreciated.
Cheers,
Zac
This smells like Big Design Up Front ( http://en.wikipedia.org/wiki/Big_Design_Up_Front )
However its very possible to invoke both controllers and action methods generically:
In asp.net mvc is it possible to make a generic controller?
Some info about invoking actions with generic action results ( which result in the same effect ).
http://www.lostechies.com/blogs/jimmy_bogard/archive/2009/12/12/enabling-ioc-in-asp-net-actionresults-or-a-better-actionresult.aspx
I am a big fan of this approach and learning about these techniques is helpful to anybody who wants to keep their controllers extraordinarily slim.
Comment Answer:
You don't really need to call the generic action method, you just need a way to pass the generic parameter to your controller. The basic flow is to include your modelType as a route parameter. You could easily call generic render actions with the correct RouteValueDictionary. Here is some sample code from an older project of mine:
Start of my generic controller:
public GenericController()
{
TypeTranslator.Configure("Brainnom.Web.Model", "Brainnom.Web");
}
[UrlRoute(Path="admin/{modelType}/add", Order=9000)]
public virtual ActionResult Add()
{
return View( new MODEL() );
}
[HttpPost]
[UrlRoute(Path = "admin/{modelType}/add", Order = 9000)]
public virtual ActionResult Add( MODEL model, string modelType)
{
if (!ModelState.IsValid)
return View(model);
var postedModel = new MODEL();
UpdateModel(postedModel);
using (var session = new MongoSession())
{
session.Add(postedModel);
}
return RedirectToRoute("Browse", new { modelType });
}
and my GenericControllerFactory ( which I do need to refactor someday )
using System;
using System.Web.Mvc;
using System.Web.Routing;
namespace Brainnom.Web.Controllers
{
public class GenericControllerFactory : DefaultControllerFactory
{
protected override Type GetControllerType(System.Web.Routing.RequestContext requestContext, string controllerName)
{
//the generic type parameter doesn't matter here
if (controllerName.EndsWith("Co"))//assuming we don't have any other generic controllers here
return typeof(GenericController<>);
return base.GetControllerType(requestContext, controllerName);
}
protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType)
{
//are we asking for the generic controller?
if (requestContext.RouteData.Values.ContainsKey("modelType"))
{
string typeName = requestContext.RouteData.Values["modelType"].ToString();
//magic time
return GetGenericControllerInstance(typeName, requestContext);
}
if (!typeof(IController).IsAssignableFrom(controllerType))
throw new ArgumentException(string.Format("Type requested is not a controller: {0}",controllerType.Name),"controllerType");
return base.GetControllerInstance(requestContext, controllerType);
}
/// <summary>
/// Returns the a generic IController tied to the typeName requested.
/// Since we only have a single generic controller the type is hardcoded for now
/// </summary>
/// <param name="typeName"></param>
/// <returns></returns>
private IController GetGenericControllerInstance(string typeName, RequestContext requestContext)
{
var actionName = requestContext.RouteData.Values["action"];
//try and resolve a custom view model
Type actionModelType = Type.GetType("Brainnom.Web.Models." + typeName + actionName + "ViewModel, Brainnom.Web", false, true) ??
Type.GetType("Brainnom.Web.Models." + typeName + ",Brainnom.Web", false, true);
Type controllerType = typeof(GenericController<>).MakeGenericType(actionModelType);
var controllerBase = Activator.CreateInstance(controllerType, new object[0] {}) as IController;
return controllerBase;
}
}
}
I am working on an ASP.NET MVC web application in which I have an object with a Uri property. The Uri contains a restful link to a resource in the following form:
/Repository/Dataset/5
The Dataset action of the Repository controller returns the contents of dataset 5 as Json.
How do I call this method from the Uri and interpret the response as Json from within the object?
Many thanks.
In server side action return JsonResult.
public ActionResult Dataset(int id)
{
// reository code
return Json(model);
}
client side call $.getJSON.
My opinion is that you should not call your controller from anywhere in code.In ASP.NET MVC Controller is there to accept request, take data and choose proper view to be returned back.
Maybe you should add method on repository that is returning already JSONized data, or introduce "Middle man" that can serialize data returned from repository so controller can call middle man to do the job. Then repository (or "Middle man") can be called from anywhere in code.
e.g.(used Json.NET for json serialization):
public class MiddleMan
{
IRepository repository
public MiddleMan(IRepository repository)
{
this.repository = repository;
}
public string GetJsonObjects(int id)
{
return JsonConvert.SerializeObject(repository.GetObject(id));
}
}
then controller (or anywhere in the code) can call this middle class:
public string Dataset(int id)
{
return new MiddleMan(repository).GetJsonObjects(id);
}
For the time being I'm going to implement a uri extension method something along these lines, creating a WebRequest object for the Uri.
public static string GetContent(this Uri uri)
{
var myRequest = (HttpWebRequest) WebRequest.Create(uri);
myRequest.Method = "GET";
WebResponse myResponse = myRequest.GetResponse();
var sr = new StreamReader(myResponse.GetResponseStream(), System.Text.Encoding.UTF8);
string result = sr.ReadToEnd();
sr.Close();
myResponse.Close();
return result;
}