My controllers return unified RequestResult:
public Task<RequestResult> SomeAction()
{
...
return new RequestResult(RequestResultType.NotFound);
}
public class RequestResult
{
public RequestResultType Type { get;set; }
... //actual data
}
public enum RequestResultType
{
Success = 1,
NotFound = 2
}
So basically RequestResult combines actual Action data and error type (if it happened). Now I need to specify Response Type at some point in case if Action returned Error. My best guess here is to use Middleware:
public class ResponseTypeMiddleware
{
private readonly RequestDelegate next;
public ResponseTypeMiddleware(RequestDelegate next)
{
this.next = next;
}
public async Task Invoke(HttpContext context)
{
await next(context);
var response = context.Response.Body; //how to access object?
}
}
but I can't figure out what to do with it. What I'd perfectly like to do is to check if response is of type RequestResult, then specify ResponseType equal BadRequest. But I don't see how I can do it here as what I have is just a stream. May be I can hijack into pipeline earlier, before result was serialized (Controller?).
P. S. The reason why I don't use Controller.BadRequest directly in Action is that my Action's logic is implemented via CQRS command/query handlers, so I don't have direct access to Controller.
As you are going to process controller's action result (MVC), the best way is to use ActionFilter or ResultFilter here, instead of Middleware. Filters in ASP.NET Core are a part of MVC and so know about controllers, actions and so on. Middleware is a more common conception - it is an additional chain in application request-response pipeline.
public class SampleActionFilter : IActionFilter
{
public void OnActionExecuting(ActionExecutingContext context)
{
// do something before the action executes
}
public void OnActionExecuted(ActionExecutedContext context)
{
// do something after the action executes
// get or set controller action result here
var result = context.Result as RequestResult;
}
}
Related
Does anyone know how I can mark an argument on ActionDescriptor.Parameters to behave in a similar way the [BindNever] is behaving?
I want to always exclude a specific argument from a specific type without keep decorating it on the Controller.
Essentially I would like to be able to add my injected to my functions somehow how similar to the way its done with CancellationToken
public class TestController : ControllerBase
{
[HttpGet(Name = "Get")]
public IActionResult Get([BindNever] IInjectedInterface injected)
{
//Injected can be used in this method
return Ok();
}
[HttpPost(Name = "Post")]
public IActionResult Post([BindNever] IInjectedInterface injected, FormModel formModel)
{
//Injected doesn't work here. There is an error that
/*System.InvalidOperationException: 'Action 'WebApplication3.Controllers.TestController.Post (WebApplication3)'
has more than one parameter that was specified or inferred as bound from request body. Only one parameter per action may be bound from body.
Inspect the following parameters, and use 'FromQueryAttribute' to specify bound from query, 'FromRouteAttribute' to specify bound from route,
and 'FromBodyAttribute' for parameters to be bound from body:
IInjectedInterface injected
FormModel formModel'
*/
return Ok();
}
}
public class ActionExecutionFilter : IAsyncActionFilter
{
public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
var injectedParam = context.ActionDescriptor.Parameters.SingleOrDefault(x => x.ParameterType == typeof(IInjectedInterface));
if (injectedParam != null)
{
context.ActionArguments[injectedParam.Name] = new Injected(99);
}
await next.Invoke();
}
private class Injected : IInjectedInterface
{
public Injected(int someData)
{
SomeData = someData;
}
public int SomeData { get; }
}
}
I was able to solve it. Apparently you need to add the following lines on your program.cs to avoid the model binder related errors.
options.ModelMetadataDetailsProviders.Add(
new ExcludeBindingMetadataProvider(typeof(IInjectedInterface)));
options.ModelMetadataDetailsProviders.Add(
new BindingSourceMetadataProvider(typeof(IInjectedInterface), BindingSource.Special));
Something very strange is happening in production, and it only happens in production. I have a Web API running and in one of the APIs, there is a repository created in the constructor and used in the functions. This is how the flow of a request works:
HTTP request comes in
MVC API controller decides which "worker" class to instantiate and creates it using Activator.CreateInstance
API controller calls worker.OnExecute inside of a Task.Run() and returns the http response
Worker calls _engine.Execute
Each worker instantiates another "engine" class that has all of the logic.
The engine in case constructs 3 repositories created using a UnitOfWork that is created per engine instance, like so:
public class MyWorker : Worker
{
private readonly MyEngine _engine;
public MyWorker()
{
_engine = new MyEngine();
}
protected override WorkerResult OnExecute(JObject data, CancellationToken cta)
{
return new WorkerResult(HttpStatusCode.OK, _engine.Execute(data));
}
}
public class MyEngine : EngineBase
{
private BaseRepository<Order> OrderRepo { get; set; }
private BaseRepository<OrderItem> OrderItemRepo { get; set; }
public MyEngine()
{
OrderRepo = new BaseRepository<Order>(MyUnitOfWork);
OrderItemRepo = new BaseRepository<OrderItem>(MyUnitOfWork);
}
public string Execute(JObject data)
{
return IsOrderValid(data).ToString();
}
public bool IsOrderValid(JObject data)
{
var orderId = data.Value<int>("OrderId");
// Without this line it crashes. With this line it crashes
//OrderRepo = new BaseRepository<Order>(InternationalWork);
// This is where it crashes
Order order = OrderRepo.First(x => x.OrderID == orderId);
// more code
}
}
public class EngineBase : UnitOfWorker, IDisposable
{
private UnitOfWork _myUnitOfWork;
public EngineBase() { }
public UnitOfWork MyUnitOfWork
{
get
{
return _myUnitOfWork ?? (_myUnitOfWork = new UnitOfWork(new DbContextAdapter(new MyDbContext())));
}
}
}
This is the actual stack trace:
The operation cannot be completed because the DbContext has been disposed.
StackTrace1
at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
at System.Data.Entity.Internal.LazyInternalContext.get_ObjectContext()
at System.Data.Entity.Internal.Linq.InternalSet`1.CreateObjectQuery(Boolean asNoTracking, Nullable`1 streaming, IDbExecutionStrategy executionStrategy)
at System.Data.Entity.Internal.Linq.InternalSet`1.InitializeUnderlyingTypes(EntitySetTypePair pair)
at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
at System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider()
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source, Expression`1 predicate)
The stack trace shows "FirstOrDefault" because OrderRepo.First internally calls DbSet.FirstOrDefault, like so:
public virtual T First(Expression<Func<T, bool>> query)
{
return _dbSet.FirstOrDefault(query);
}
I'm stumped because each worker is created per http request. Each DBContext is created per engine instance so I don't know how it could be disposed when it was just created in the constructor. And this only happens on the production web server where I presume it's being called more. Any tips would be greatly appreciated.
I'm trying to add a bunch of custom data fields to every piece of telemetry I can, and this data is consistent across a single operation, but varies from operation to operation.
I have a custom ITelemetryInitializer, and within that I can do something like:
public class MyInitializer : ITelemetryInitializer
{
public void Initialize(Microsoft.ApplicationInsights.Channel.ITelemetry telemetry)
{
telemetry.Context.Properties[ "platform" ] = "PC";
}
}
But I don't understand how I'm suppose to push this data into this initializer.
I've added something like this:
public class MyInitializer : ITelemetryInitializer
{
private string mPlatform = "unknown";
public void Initialize(Microsoft.ApplicationInsights.Channel.ITelemetry telemetry)
{
telemetry.Context.Properties[ "platform" ] = mPlatform;
}
public void SetPlatform(string platform)
{
mPlatform = platform
}
}
And then at the controller level I do something like this:
foreach (var init in TelemetryConfiguration.Active.TelemetryInitializers)
{
var customInit = init as MyInitializer;
if (customInit != null)
{
customInit.SetPlatform(requestPlatform);
}
}
But this is horribly clunky, and prone to error (e.g. if a piece of telemetry gets sent before this function is called), and I'm not really sure if this is thread-safe.
What's the intended way of passing around this kind of data?
I think I've solved this now, the solution is to write to the properties of the TelemetryClient within the controller like this:
[Route( "[controller]" )]
public class MyController : Controller
{
private readonly TelemetryClient mTelemetryClient;
public MyController(
TelemetryClient TelemetryClientArg )
{
mTelemetryClient = TelemetryClientArg;
mTelemetryClient.Context.Properties.Remove("platform");
}
[HttpPost]
[Produces( "application/json" )]
public IActionResult Post( [FromBody] RequestClass RequestData )
{
mTelemetryClient.TrackTrace("Test trace 1"); // doesn't have platform set
mTelemetryClient.Context.Properties["platform"] = RequestData.platform;
mTelemetryClient.TrackTrace("Test trace 2"); // has platform set correctly
}
}
This seems to be safe as the controller constructor appears to be called before each http request is processed and the context within the TelemetryClient is unique per thread. I would like to get confirmation from the team that this is reasonable.
Currently I have a simple custom policy handler that looks like so:
protected override void Handle(AuthorizationContext context, UserPolicyRequirement requirement)
{
// authorize user against policy requirements
if (_authorizationTask.AuthorizeUserAgainstPolicy(context.User, requirement))
{
// User passed policy req's
context.Succeed(requirement);
}
}
Problem is, this authorization step takes a long time to execute, but this is required in many different areas of the website. Is there any readily available mechanisms to save/cache the results of this policy authorization so that I only need to do this once per session?
I am currently using Windows Authentication, if that helps.
If per session way does not cause any problem, you can use Session to store user data. Simple implementation is something like below:
First you need a service to get user data from any store
public interface IGetUserDataService
{
<type> GetUserData();
}
I assume that there is Session configuration(see) and IGetUserDataService implementation.
Then you need to create a middleware to handle Session
public class SessionMiddleware
{
private readonly RequestDelegate _next;
private readonly IGetUserDataService _getUserDataService;
public SessionMiddleware(RequestDelegate next, IGetUserDataService getUserDataService)
{
_next = next;
_getUserDataService = getUserDataService;
}
public async Task Invoke(HttpContext context)
{
//user data is obtained only once then is stored in Session
if (context.Session.Get("UserData") == null)
{
context.Session.Set("UserData", getUserDataService.GetData());
}
await _next.Invoke(context);
}
}
//In Startup.cs
app.UseMiddleware<SessionMiddleware>();
Finally get and use session data in handler
public class YourHandler : AuthorizationHandler<YourRequirement>
{
private readonly IHttpContextAccessor _accessor;
public YourHandler(IHttpContextAccessor accessor)
{
_accessor = accessor;
}
protected override void Handle(AuthorizationContext context, PermissionRequirement requirement)
{
var userData =(<type>)_accessor.HttpContext.Session.Get("UserData");
// check
}
}
In a WEBAPI filter, im trying to calculate response size.
A similar process works for MVC controllers.
Inside actionExecutedContext.Response. i cant see a filter?
So I tried this filter below but this doesnt work.
How can i get the length of a WEBApi response ?
I could stick this in Global.ASAX and it works, but then every http call is logged...
So an API filter would be ideal. Is there something obviously wrong here ?
public class BosAPIFilter : System.Web.Http.Filters.ActionFilterAttribute{
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext) {
base.OnActionExecuted(actionExecutedContext);
var httpContext = actionExecutedContext.Request.Properties["MS_HttpContext"] as HttpContextWrapper;
if (httpContext != null) {
actionExecutedContext.Response.
httpContext.Response.Filter = new ResponseStreamHandler(httpContext.Response.Filter);
var handler = httpContext.Response.Filter as ResponseStreamHandler;
var adminService = new AdminServices();
adminService.HttpTrace(httpContext, handler);
}
}
public class ResponseStreamHandler : MemoryStream {
private readonly Stream _responseStream;
public long ResponseSize { get; private set; }
public ResponseStreamHandler(Stream responseStream) {
this._responseStream = responseStream;
ResponseSize = 0;
}
public override void Write(byte[] buffer, int offset, int count) {
this.ResponseSize += count;
this._responseStream.Write(buffer, offset, count);
}
// ReSharper disable once RedundantOverridenMember
public override void Flush() { base.Flush(); }
}
In ASP.NET Web API pipeline, action filters run before the result you return from the action method gets serialized. If you look at actionExecutedContext.Response.Content inside the filter, it will be System.Net.Http.ObjectContent (depending on your action method). So, you can calculate the response size only later in the pipeline. You can use a message handler to do this but then the granularity is not at the action method level. The lowest granularity you can get is at a route level. One way you get around this is to set a flag in the request dictionary from the filter and log from the handler only when the flag is set.