I wanted to save notification in TempData and shown to user. I create extension methods for this and implement a class which Extends from ActionResult. I need to access TempData in override ExecuteResult method with ActionContext.
Extension Method:
public static IActionResult WithSuccess(this ActionResult result, string message)
{
return new AlertDecoratorResult(result, "alert-success", message);
}
Extends ActionResult class.
public class AlertDecoratorResult : ActionResult
{
public ActionResult InnerResult { get; set; }
public string AlertClass { get; set; }
public string Message { get; set; }
public AlertDecoratorResult(ActionResult innerResult, string alertClass, string message)
{
InnerResult = innerResult;
AlertClass = alertClass;
Message = message;
}
public override void ExecuteResult(ActionContext context)
{
ITempDataDictionary tempData = context.HttpContext.RequestServices.GetService(typeof(ITempDataDictionary)) as ITempDataDictionary;
var alerts = tempData.GetAlert();
alerts.Add(new Alert(AlertClass, Message));
InnerResult.ExecuteResult(context);
}
}
Call extension method from controller
return RedirectToAction("Index").WithSuccess("Category Created!");
I get 'TempData ' null , How can I access 'TempData' in 'ExecuteResult' method.
I was literally trying to do the exact same thing today (have we seen the same Pluralsight course? ;-) ) and your question led me to find how to access the TempData (thanks!).
When debugging I found that my override on ExecuteResult was never called, which led me to try the new async version instead. And that worked!
What you need to do is override ExecuteResultAsync instead:
public override async Task ExecuteResultAsync(ActionContext context)
{
ITempDataDictionaryFactory factory = context.HttpContext.RequestServices.GetService(typeof(ITempDataDictionaryFactory)) as ITempDataDictionaryFactory;
ITempDataDictionary tempData = factory.GetTempData(context.HttpContext);
var alerts = tempData.GetAlert();
alerts.Add(new Alert(AlertClass, Message));
await InnerResult.ExecuteResultAsync(context);
}
However, I have not fully understood why the async method is called as the controller is not async... Need to do some reading on that...
I find out the way to get the TempData. It need to get from ITempDataDictionaryFactory
var factory = context.HttpContext.RequestServices.GetService(typeof(ITempDataDictionaryFactory)) as ITempDataDictionaryFactory;
var tempData = factory.GetTempData(context.HttpContext);
Related
So Basically i wrote a validator for my class with FluentValidation and also a filter to do the validation task for me in my webAPI project, so far it's OK but assume that my User class has firstname,lastname,email,password properties
and i have two routes (one for register and the other one for login)
and as you might have noticed required properties are different on these route.
Thus,should I really need to write individual validation for each and every action i have?because this makes a lot of code code duplication and it's hard to change.is there any way to just add required condition based on the request coming with single validation class?
Any suggestion???
A better practice would be to use a factory pattern for your validations and use a an action filter to short circuit bad requests. You could validate any action argument(Headers, Request Bodies, etc..) with something like this.
public class TestValidationAttribute : Attribute, IActionFilter
{
private string _requestModelName;
public TestValidationAttribute(string requestModelName)
{
_requestModelName = requestModelName;
}
public void OnActionExecuting(ActionExecutingContext context)
{
// using Microsoft.Extensions.DependencyInjection;
var services = context.HttpContext.RequestServices;
var accessor = services.GetService<IHttpContextAccessor>();
var factory = services.GetService<ITestValidatorFactory>();
var tokens = accessor.HttpContext.GetRouteData().DataTokens;
if (!tokens.TryGetValue("RouteName", out var routeNameObj))
{
throw new Exception($"Action doesn't have a named route.");
}
var routeName = routeNameObj.ToString();
var validator = factory.Create(routeName);
if (!context.ActionArguments.TryGetValue(_requestModelName, out var model))
{
throw new Exception($"Action doesn't have argument named {_requestModelName}.");
}
TestModel test;
try
{
test = (TestModel) model;
}
catch (InvalidCastException)
{
throw new Exception($"Action argument can't be casted to {nameof(TestModel)}.");
}
var validation = validator.Validate(test);
if (!validation.Successful)
{
context.Result = new BadRequestObjectResult(validation.ResponseModel);
}
}
public void OnActionExecuted(ActionExecutedContext context)
{
}
}
public class TestController : Controller
{
[HttpPost]
[Route("Test/{id}", Name = "TestGet")]
[TestValidation("model")]
public IActionResult Test(TestModel model)
{
return Ok();
}
}
public class ValidationResult
{
public bool Successful { get; }
public ResponseModel ResponseModel { get; }
}
public class TestModel
{
}
public interface ITestValidator
{
ValidationResult Validate(TestModel model);
}
public interface ITestValidatorFactory
{
ITestValidator Create(string routeName);
}
I am having a bit of issues with my Web API 2 project.
In order to connect to a mobile app client i will need to provide with custom success / error object in this way:
Products (GET)
on Success 200: return a list with (ID, Name)
on Error: return a custom object with (ErrorCode, ErrorDescription)
How can I do this in a nice way?
Using JsonResult or is there a better way?
I would do it like this:
public class CustomErrorObject
{
public string ErrorCode { get; set; }
public string ErrorDescription { get; set; }
}
public class HandleApiExceptionAttribute : ExceptionFilterAttribute
{
public override void OnException(System.Web.Http.Filters.HttpActionExecutedContext actionExecutedContext)
{
base.OnException(actionExecutedContext);
HttpRequestMessage request = actionExecutedContext.ActionContext.Request;
CustomErrorObject response = new CustomErrorObject();
response.ErrorCode = actionExecutedContext.Exception.Data("Text");
response.ErrorDescription = actionExecutedContext.Exception.Data("Detail");
actionExecutedContext.Response = request.CreateResponse(HttpStatusCode.BadRequest, response);
}
}
Then in the Global.asax add this line to the Application_Start event:
GlobalConfiguration.Configuration.Filters.Add(new HandleApiExceptionAttribute())
If you'd like to know more about exception handling in Web API: here
I need to access a property inside a custom DataAnnotation attribute. How can I access this attribute in order to set the response value? The attribute is added to the model property.
public class BirthDateAttribute : ValidationAttribute
{
public string ErrorCode { get; set; }
....
}
public class ValidateModelAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(HttpActionContext actionContext)
{
if (!actionContext.ModelState.IsValid)
{
List<Errors> errors = new List<Errors>();
// Set error message and errorCode
foreach (var key in keys)
{
if (!actionContext.ModelState.IsValidField(key))
{
error.Add(new HttpResponseError
{
Code = ???????????,
Message = actionContext.ModelState[key].Errors.FirstOrDefault().ErrorMessage
});
}
}
// Return to client
actionContext.Response = actionContext.Request.CreateResponse(
HttpStatusCode.BadRequest, errors);
}
}
}
Assuming that the custom attribute is applied to the controller, you can try following in the OnActionExecuting event. This similar thing works with MVC controller but should work with API controller too.
var att = actionContext.ControllerContext.GetType().GetCustomAttributes(typeof(BirthDateAttribute), false)[0] as BirthDateAttribute;
string errorCode = att.ErrorCode;
As mentioned by OP, if this is on a class (Model), it should be pretty starightforward because the type is already known. Replace the Model class.
var att = <<ModalClass>>.GetCustomAttributes(typeof(BirthDateAttribute), false)[0] as BirthDateAttribute;
string errorCode = att.ErrorCode;
I am working on an MVC project where controller actions deal with Assets. Different controllers take in the assetId parameter in different way: Some controllers simply get int assetId, other int id, and other using a complex object AssetDTO dto (which contains a property that holds the assetId)
I am writing an ActionFilter that is added to the action method and is provided with the actionParameter name where I can get the asset value.
Action Method:
[AssetIdFilter("assetId")]
public ActionResult Index(int assetId)
{
...
}
The attribute is defined as:
public class AssetIdFilterAttribute : ActionFilterAttribute
{
public string _assetIdParameterKey { get; set; }
public AssetIdFilterAttribute (string assetIdParameterKey)
{
_assetIdParameterKey = assetIdParameterKey;
}
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
int assetId;
if (Int32.TryParse(filterContext.ActionParameters[_assetIdParameterKey].ToString(), out assetId))
{
......
}
}
This works as expected, but will only work when the assetId is provided as a primitive. I am not sure what to do when the assetId is provided within a complex object into the action method.
Will I need to parse each object differently depending on the type? I am hoping I can specify some kind of dot-notation in the AssetIdFilter to tell it where the assetId is located: dto.assetId
Any way I can use dynamics? or reflection?? ect.???
and here dynamic comes to the rescue.you can change the actionFilterAttribute to be :
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
dynamic assetIdHolder = filterContext.ActionParameters[_assetIdParameterKey];
if (assetIdHolder.GetType().IsPrimitive)
{
//do whatever with assetIdHolder
}
else
{
//do whatever with assetIdHolder.assetId
}
}
cheers!
Well, yes, you answered your question. One way would be to use dot notation:
//simple case:
[AssetId("id")]
public ActionResult Index(string id) {
//code here
}
//complex case:
[AssetId("idObj", AssetIdProperty = "SubObj.id")]
public ActionResult index(IdObject idObj) {
//code here
}
And AssetIdAttribute is as follows:
public class AssetIdAttribute : ActionFilterAttribute
{
public string _assetIdParameterKey { get; set; }
public string AssetIdProperty { get; set; }
public AssetIdFilterAttribute(string assetIdParameterKey)
{
_assetIdParameterKey = assetIdParameterKey;
}
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
int assetId;
var param = filterContext.ActionParameters[_assetIdParameterKey];
int.TryParse(GetPropertyValue(param, this.AssetIdProperty).ToString(), out assetId);
//you code continues here.
}
private static string GetPropertyValue(object souce, string property)
{
var propNames = string.IsNullOrWhiteSpace(property) || !property.Contains('.') ? new string[] { } : property.Split('.');
var result = souce;
foreach (var prop in propNames)
{
result = result.GetType().GetProperty(prop).GetValue(result);
}
return result.ToString();
}
}
The code does not have null checks when calling ToString and when calling GetProperty though. Also, it does not check the success of TryParse. Please apply these corrections when used.
Maybe this code could be written using dynamic, but at the end dynamic usage is compiled into object using reflection (something like what I have done here), thus no big difference to me.
Also, maybe it would be more clear to have a parameter like "idObj.SubObj.id", but that again depends on the preference, and the code will become a little bit more complex.
I'm using MVC3 and currently i'm following a practice such that I declare one instance of DB Container for every controller. I use that container instance for every request coming to that controller. If I need to go to my models for a query or sth, I send that instance as a parameter to the model's function. So for the whole application, I create and use 4-5 different instances of DB Container class. My question is, does this have a good or bad effect on my database operations? Does it matter to create a seperate container instance? What is the proper way to use container classes?
I believe the mentioned class was called DBContext before.
I am not sure it is what you mean but I can give you an example of an approach I'm following rather often:
Create a sort of 'domainservice class' for the DBContext
public class MyDomainService : IDisposable
{
private MyDbEntities dbo;
private bool isDisposed;
public MyDomainService()
{
dbo = new MyDbEntities();
}
public User GetUser(string userName)
{
return (from usr in dbo.Users
where usr.UserName == userName
select usr).SingleOrDefault();
}
public void Dispose()
{
if (isDisposed)
return;
isDisposed = true;
dbo.Dispose();
}
}
Create a custom Controller class that extends Controller or AsyncController
and override the Initialize and Dispose methods:
public class MyController : Controller
{
protected MyDomainService DomainService { get; private set; }
protected override void Initialize(System.Web.Routing.RequestContext
requestContext)
{
base.Initialize(requestContext);
DomainService = new MyDomainService();
}
protected override void Dispose(bool disposing)
{
DomainService.Dispose();
base.Dispose(disposing);
}
}
Now you can use the following approach in per example the HomeController inheriting MyController
public class HomeController : MyController
{
public ActionResult Index()
{
return View();
}
[HttpPost]
public ActionResult Index(string username)
{
var user = DomainService.GetUser(username);
if (user != null)
return RedirectToAction("Account", "Information");
return View();
}
}
This will keep your controllers rather clean.