I am building an application using Ninject and ASP.NET MVC 3.
Is it possible with Ninject to supply a generic binding within a module like this:
Bind(typeof(IRepository<>)).To(typeof(SomeConcreteRepository<>));
EDIT:
And then for a specific type , create a class that inherits from SomeConcreteRepository:
Bind(typeof(IRepository<Person>)).To(typeof(PersonConcreteRepository));
This throws an exception that multiple bindings are available. However, is there another approach to this? Are there other DI frameworks for .NET which support this behavior?
You don't need the second line. Simply register the open generic types:
kernel.Bind(typeof(IRepository<>)).To(typeof(SomeConcreteRepository<>));
and later fetch a specific repository like this:
var repo = kernel.Get<IRepository<Person>>();
or you can also use a provider.
A bit of a nasty fix but for the scenario at hand it works:
public class MyKernel: StandardKernel
{
public MyKernel(params INinjectModule[] modules) : base(modules) { }
public MyKernel(INinjectSettings settings, params INinjectModule[] modules) : base(settings, modules) { }
public override IEnumerable<IBinding> GetBindings(Type service)
{
var bindings = base.GetBindings(service);
if (bindings.Count() > 1)
{
bindings = bindings.Where(c => !c.Service.IsGenericTypeDefinition);
}
return bindings;
}
}
public class ExtendedNinjectKernal : StandardKernel
{
public ExtendedNinjectKernal(params INinjectModule[] modules) : base(modules) { }
public ExtendedNinjectKernal(INinjectSettings settings, params INinjectModule[] modules) : base(settings, modules) { }
public override IEnumerable<IBinding> GetBindings(Type service)
{
var bindings = base.GetBindings(service);
//If there are multiple bindings, select the one where the service does not have generic parameters
if (bindings.Count() > 1 && bindings.Any(a => !a.Service.IsGenericTypeDefinition))
bindings = bindings.Where(c => !c.Service.IsGenericTypeDefinition);
return bindings;
}
}
Related
I want to create and AMP version of my website in ASP.NET MVC using .NET Core 2.0. Previously I had done some work with DisplayModeProvider instances in tha past on .Net framework, but that does not seem to be an option in .NET Core.
What I want to be able to do is alter the view names to be index.amp.cshtml rather than index.cshtml when my URL starts iwth /amp. What's the best way to achieve this in .NET Core?
You can do something like this using IViewLocationExpander. As it happens, I was playing with this a few days ago so I have some code samples to hand. If you create something like this:
public class AmpViewLocationExpander : IViewLocationExpander
{
public void PopulateValues(ViewLocationExpanderContext context)
{
var contains = context.ActionContext.HttpContext.Request.Query.ContainsKey("amp");
context.Values.Add("AmpKey", contains.ToString());
var containsStem = context.ActionContext.HttpContext.Request.Path.StartsWithSegments("/amp");
context.Values.Add("AmpStem", containsStem.ToString());
}
public IEnumerable<string> ExpandViewLocations(ViewLocationExpanderContext context, IEnumerable<string> viewLocations)
{
if (!(context.ActionContext.ActionDescriptor is ControllerActionDescriptor descriptor)) { return viewLocations; }
if (context.ActionContext.HttpContext.Request.Query.ContainsKey("amp")
|| context.ActionContext.HttpContext.Request.Path.StartsWithSegments("/amp")
)
{
return viewLocations.Select(x => x.Replace("{0}", "{0}.amp"));
}
return viewLocations;
}
}
iViewLocationExpander can be found in Microsoft.AspNetCore.Mvc.Razor
Then in your Configure Services method in Startup.cs, add the following:
services.Configure<RazorViewEngineOptions>(options =>
{
options.ViewLocationExpanders.Add(new AmpViewLocationExtender());
});
What this will do is update the view locations per request to insert .amp before .cshtml any time the URL either starts with /amp or there is a query string key of amp. If your AMP views don't exist, it might blow-up a little, I've not fully tested it, but it should get you started.
You can define this Middleware :
public class AmpMiddleware
{
private RequestDelegate _next;
public AmpMiddleware(RequestDelegate next)
{
_next = next;
}
public Task Invoke(HttpContext context)
{
const string ampTag = "/amp";
var path = context.Request.Path;
if (path.HasValue)
{
var ampPos = path.Value.IndexOf(ampTag);
if (ampPos >= 0)
{
context.Request.Path = new PathString(path.Value.Remove(ampPos, ampTag.Length));
context.Items.Add("amp", "true");
}
}
return _next(context);
}
}
public static class BuilderExtensions
{
public static IApplicationBuilder UseAmpMiddleware(this IApplicationBuilder app)
{
return app.UseMiddleware<AmpMiddleware>();
}
}
And call it in Startup:
app.UseAmpMiddleware();
Then can check in page and simple set another layout or limit some code, in his way no need to create separate page for amp version:
#if (HttpContext.Items.ContainsKey("amp"))
{
<b>Request AMP Version</b>
}
I am trying to find a way to be able to set from the View to what ViewModel I have to navigate. This is to be able to change the navigation flow without changing the core project.
I thought the easier way would be creating an interface, setting the target ViewModel there and injecting the interface into the ViewModel to then perform the navigation.
public interface IModelMapping
{
MvxViewModel ViewModelToNavigate();
}
public class MyViewModel : MvxViewModel
{
readonly IMvxNavigationService navigationService;
readonly IModelMapping modelMapping;
public MyViewModel(IMvxNavigationService navigationService, IModelMapping modelMapping)
{
this.navigationService = navigationService;
this.modelMapping = modelMapping;
}
public IMvxAsyncCommand GoContent
{
get
{
IMvxViewModel vm = modelMapping.ViewModelToNavigate();
IMvxAsyncCommand navigateCommand = new MvxAsyncCommand(() => navigationService.Navigate<vm>());
return navigteCommand;
}
}
}
The problem with this code is I am getting an error setting the navigationService.Navigate(). The error is 'vm is a variable but it is used like a type'
What about using the URI navigation together with the facade? See also https://www.mvvmcross.com/documentation/fundamentals/navigation#uri-navigation
Say you are building a task app and depending on the type of task you want to show a different view. This is where NavigationFacades come in handy (there is only so much regular expressions can do for you).
mvx://task/?id=00 <– this task is done, show read-only view (ViewModelA)
mvx://task/?id=01 <– this task isn’t, go straight to edit view (ViewModelB)
[assembly: MvxRouting(typeof(SimpleNavigationFacade), #"mvx://task/\?id=(?<id>[A-Z0-9]{32})$")]
namespace *.NavigationFacades
{
public class SimpleNavigationFacade
: IMvxNavigationFacade
{
public Task<MvxViewModelRequest> BuildViewModelRequest(string url,
IDictionary<string, string> currentParameters, MvxRequestedBy requestedBy)
{
// you can load data from a database etc.
// try not to do a lot of work here, as the user is waiting for the UI to do something ;)
var viewModelType = currentParameters["id"] == Guid.Empty.ToString("N") ? typeof(ViewModelA) : typeof(ViewModelB);
return Task.FromResult(new MvxViewModelRequest(viewModelType, new MvxBundle(), null, requestedBy));
}
}
}
I have a ASP.NET Web API (.NET 4) application which has a few controllers. We will run several instances of the Web API application on IIS with one difference. Only certain controllers will be available under certain IIS instances. What I was thinking is to disable/unload the controllers that are not applicable to an instance when the instance starts up.
Anyone got some information that could guide me in the right direction on this?
You can put your own custom IHttpControllerActivator in by decorating the DefaultHttpControllerActivator. Inside just check for a setting and only create the controller if allowed.
When you return null from the Create method the user will receive 404 Not Found message.
My example shows a value in App Settings (App.Config or Web.Config) being checked but obviously this could any other environment aware condition.
public class YourCustomControllerActivator : IHttpControllerActivator
{
private readonly IHttpControllerActivator _default = new DefaultHttpControllerActivator();
public YourCustomControllerActivator()
{
}
public IHttpController Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor,
Type controllerType)
{
if (ConfigurationManager.AppSettings["MySetting"] == "Off")
{
//Or get clever and look for attributes on the controller in controllerDescriptor.GetCustomAttributes<>();
//Or use the contoller name controllerDescriptor.ControllerName
//This example uses the type
if (controllerType == typeof (MyController) ||
controllerType == typeof (EtcController))
{
return null;
}
}
return _default.Create(request, controllerDescriptor, controllerType);
}
}
You can switch your activator in like so:
GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerActivator), new YourCustomControllerActivator());
Update
It has been a while since I looked at this question but if I was to tackle it today I would alter the approach slightly and use a custom IHttpControllerSelector. This is called before the activator and makes for a slightly more efficient place to enable and disable controllers... (although the other approach does work). You should be able to decorate or inherit from DefaultHttpControllerSelector.
Rather than unloading the controllers, I think I'd create a custom Authorize attribute that looked at the instance information in deciding to grant authorization.
You would add the following to each controller at the class level, or you could also add this to individual controller actions:
[ControllerAuthorize (AuthorizedUserSources = new[] { "IISInstance1","IISInstance2","..." })]
Here's the code for the Attribute:
public class ControllerAuthorize : AuthorizeAttribute
{
public ControllerAuthorize()
{
UnauthorizedAccessMessage = "You do not have the required access to view this content.";
}
//Property to allow array instead of single string.
private string[] _authorizedSources;
public string UnauthorizedAccessMessage { get; set; }
public string[] AuthorizedSources
{
get { return _authorizedSources ?? new string[0]; }
set { _authorizedSources = value; }
}
// return true if the IIS instance ID matches any of the AllowedSources.
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
if (httpContext == null)
throw new ArgumentNullException("httpContext");
//If no sources are supplied then return true, assuming none means any.
if (!AuthorizedSources.Any())
return true;
return AuthorizedSources.Any(ut => ut == httpContext.ApplicationInstance.Request.ServerVariables["INSTANCE_ID"]);
}
The IHttpControllerActivator implementation doesn't disable the routes defined using attribute routing , if you want to switch on/off a controller and have a default catch all route controller. Switching off using IHttpControllerActivator disables the controller but when the route is requested it doesn't hit the catch all route controller -it simply tries to hit the controller that was removed and returns no controller registered.
I used an example on extensible asp.net mvc 3 to build my plug-able application, but I encountered a problem. In a plug-in I declared and implmemented an interface.
But, in plug-in controller when I want to use this class, the application throws an error and it seems that EntityConfig was not initialized. How can this be fixed?
[Export(typeof(IController)), ExportMetadata("controllerName", "Concept")]
[PartCreationPolicy(CreationPolicy.NonShared)]
public class ConceptController : Controller
{
[Import(typeof(IEntityConfig))]
private IEntityConfig EntityConfig;
public ActionResult Index()
{
var obs = EntityConfig.EntityName;
return View("~/Bin/Views/Concept/Index.cshtml",obs );
}
}
public interface IEntityConfig
{
string EntityName { get;}
}
[Export(typeof(IEntityConfig))]
public class TestEntity : IEntityConfig
{
public string EntityName
{
get{return "Test";}
}
}
Edited :
In other side, when I is use this example, there is no problem in resolving EntityConfig, but in the view, when I want to load model as follows :
#using Concepts
#model Concepts.Models.TestModel
the application throws an error and tells me 'The type or namespace name 'Concepts' could not be found', although when I check container after it was initiated, I can see Concepts in in loaded assemblies.
Would you please help me ?
Thanks.
Edited :
I uploaded the samples :
First one
Second one
Edited (2011/22/09):
I tested the above code on other sample that #Matthew Abbott provided in his blog, and it worked, although this sample has been built against mvc 2.0.
Looking over your code, can you be sure that the part is actually being imported? Your constructor code for your composition container is such like:
var discoverableControllerFactory = new DiscoverableControllerFactory(
new CompositionContainer(
new DirectoryCatalog(extensionsPath))
);
You're only including your extensions path as a catalog. Can you guaruntee that you're also including your base application path, e.g.:
var discoverableControllerFactory = new DiscoverableControllerFactory(
new CompositionContainer(
new AggregateCatalog(
new DirectoryCatalog("bin"),
new DirectoryCatalog(extensionsPath)))
);
If the parts actually exist in your Unity container, you could add an export provider that grabs those parts from that container and allows them to be composed by MEF.
As for your second problem, you will need to subclass the System.Web.WebPages.Razor.RazorBuildProvider to ensure it includes assemblies in your extensions directory:
namespace ExtensibleMvcApplication
{
public class CustomRazorBuildProvider : RazorBuildProvider
{
public static IEnumerable<Assembly> _assemblies;
static CustomRazorBuildProvider()
{
string extensionsPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Extensions");
_assemblies = Directory.GetFiles(extensionsPath, "*.dll")
.Select(Assembly.Load);
}
public override void GenerateCode(System.Web.Compilation.AssemblyBuilder assemblyBuilder)
{
foreach (var assembly in _assemblies)
assemblyBuilder.AddAssemblyReference(assembly);
base.GenerateCode(assemblyBuilder);
}
}
}
Which you'd need to register in your config:
<buildProviders>
<remove extension=".cshtml" />
<add extension=".cshtml" type="ExtensibleMvcApplication.CustomRazorBuildProvider, ExtensibleMvcApplication"/>
</buildProviders>
I've just started to use AutoMapper in my MVC 3 project and I'm wondering how people here structure their projects when using it. I've created a MapManager which simply has a SetupMaps method that I call in global.asax to create the initial map configurations. I also need to use a ValueResolver for one of my mappings. For me, this particular ValueResolver will be needed in a couple of different places and will simply return a value from Article.GenerateSlug.
So my questions are:
How do you manage the initial creation of all of your maps (Mapper.CreateMap)?
Where do you put the classes for your ValueResolvers in your project? Do you create subfolders under your Model folder or something else entirely?
Thanks for any help.
i won't speak to question 2 as its really personal preference, but for 1 i generally use one or more AutoMapper.Profile to hold all my Mapper.CreateMap for a specific purpose (domaintoviewmodel, etc).
public class ViewModelToDomainAutomapperProfile : Profile
{
public override string ProfileName
{
get
{
return "ViewModelToDomain";
}
}
protected override void Configure()
{
CreateMap<TripRegistrationViewModel, TripRegistration>()
.ForMember(x=>x.PingAttempts, y => y.Ignore())
.ForMember(x=>x.PingResponses, y => y.Ignore());
}
}
then i create a bootstrapper (IInitializer) that configures the Mapper, adding all of my profiles.
public class AutoMapperInitializer : IInitializer
{
public void Execute()
{
Mapper.Initialize(x =>
{
x.AddProfile<DomainToViewModelAutomapperProfile>();
x.AddProfile<ViewModelToDomainAutomapperProfile>();
});
}
}
then in my global.asax i get all instances of IInitializer and loop through them running Execute().
foreach (var initializer in ObjectFactory.GetAllInstances<IInitializer>())
{
initializer.Execute();
}
that's my general strategy.
by request, here is the reflection implementation of the final step.
var iInitializer = typeof(IInitializer);
List<IInitializer> initializers = AppDomain.CurrentDomain.GetAssemblies()
.SelectMany(s => s.GetTypes())
.Where(p => iInitializer.IsAssignableFrom(p) && p.IsClass)
.Select(x => (IInitializer) Activator.CreateInstance(x)).ToList();
foreach (var initializer in initializers)
{
initializer.Execute();
}