Say I have the controller as follows:
public class Controller
{
ISomeService _service;
public Controller(ISomeService service)
{
_service = service;
_service.EventFired += EventFired;
_service.SomeEventFired += SomeOtherEventFired;
}
private void EventFire(object sender, EventArgs e)
{
// Might occur on FireSomeEvents();
// Go to another controller
}
private void SomeOtherEventFired(object sender, EventArgs e)
{
// Might occur on FireSomeEvents();
// Go to another view on this page
}
public void Create()
{
_service.FireSomeEvents();
if(EventFired == true)
{
return View("EventFired");
}
else
{
return RedirectToAction("SomeOtherEventFired");
}
}
}
I want to be able to handle the Redirect and View in a better way, because in the end I will end up with 3 potential events on my service.
I'm just wondering whether this is a design smell, or whether there is a better way to implement the redirect to pages...
Events don't play nicely with ASP.NET MVC. Their model is not adapted to the MVC pattern. If you want to use them you may take a look at asynchronous controllers.
Related
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;
}
}
I have these code, according to document from sitefinity:
protected void Application_Start(object sender, EventArgs e)
{
Bootstrapper.Initialized += new EventHandler<ExecutedEventArgs>(Bootstrapper_Initialized);
}
public void Bootstrapper_Initialized(object sender, ExecutedEventArgs args)
{
if (args.CommandName == "Bootstrapped")
{
EventHub.Subscribe<ICommentEvent>(evt => CommentsEvent.CommentEventHandler(evt));
}
}
And the handler:
public static void CommentEventHandler(ICommentEvent evt)
{
// My code here
}
The problem is this handler always runs twice when a comment event happens (post a comment or approve a comment).
Could you please tell me why this happens and any possible way to avoid this? (I don't believe static boolean is a good idea).
Thanks
ICommentEvent is a base interface that is implemented by multiple events such as ICommentCreatingEvent, ICommentCreatedEvent, ICommentUpdatingEvent, ICommentUpdatedEvent and some others.
In your case it is fired twice due to firing of both ICommentCreatingEvent and ICommentCreatedEvent.
You can subscribe to just one of them and it should fire just once.
I have figured out how to log when a request is an ajax request and which page it is from, in a filter.
What I would really like to do is log what the ajax request is actually for. Such as the name of the method being called by the ajax (eg "findAddress" in this call:<p:ajax process="contactDetails" update="#form" listener="#{aboutYouController.findAddress}" .... )
How can I do this? My app has many ajax requests and I want to log which are being triggered.
public class TrackingFilter implements Filter {
private static Logger LOG = Logger.getLogger(TrackingFilter.class);
#Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
HttpServletRequest req = (HttpServletRequest) request;
String pageHit = req.getRequestURI().substring(req.getContextPath().length()+1).replace(".xhtml", "");
if(!pageHit.contains("javax.faces.resource")){ // if is a url we want to log
if ("partial/ajax".equals(req.getHeader("Faces-Request"))) {
LOG.trace("ajax on URI: " + req.getRequestURI());
}
What I would really like to do is log what the ajax request is actually for. Such as the name of the method being called by the ajax (eg "findAddress" in this call:<p:ajax process="contactDetails" update="#form" listener="#{aboutYouController.findAddress}" ....)
This information is only available in the JSF component tree. The JSF component tree is only available after view build time. A view is only built when the request has been served by FacesServlet. Thus, a servlet filter is way too early as it runs before any servlet.
You'd better run the code after the restore view phase of a postback. The JSF component tree is guaranteed to be available during that moment. You can use FacesContext#isPostback() to check if the current request is a postback. You can use PartialViewContext#isAjaxRequest() to check if the current request is an ajax request. You can use the predefined javax.faces.source request parameter to obtain the client ID of the source component of the ajax request. You can use the predefined javax.faces.behavior.event request parameter to obtain the ajax event name (e.g. change, click, action, etc).
Obtaining the associated behavior listeners is in turn a story apart. This is easy on ActionSource2 components (e.g. <h|p:commandButton action="#{...}">) as the MethodExpression is just available by ActionSource2#getActionExpression(). However, this isn't easy on BehaviorBase taghandlers (e.g. <f|p:ajax listener="#{...}">) as this API doesn't have any method like getBehaviorListeners(). There are only methods to add and remove them, but not to obtain a list of them. So some nasty reflection trickery is necessary to access the private field with those listeners whose name is JSF implementation specific. In Mojarra it's listeners and in MyFaces it's _behaviorListeners. Both are fortunately assignable from List and it's the only field of that type, so we could just check for that. Once having hand of the BehaviorListener instance, then you still need to do another reflection trickery to obtain the MethodExpression field of that instance. Yuck.
All in all, here's how the trickery look like in flavor of a PhaseListener listening on afterPhase of RESTORE_VIEW:
public class AjaxActionLoggerPhaseListener implements PhaseListener {
#Override
public PhaseId getPhaseId() {
return PhaseId.RESTORE_VIEW;
}
#Override
public void beforePhase(PhaseEvent event) {
// NOOP.
}
#Override
public void afterPhase(PhaseEvent event) {
FacesContext context = event.getFacesContext();
if (!(context.isPostback() && context.getPartialViewContext().isAjaxRequest())) {
return; // Not an ajax postback.
}
Map<String, String> params = context.getExternalContext().getRequestParameterMap();
String sourceClientId = params.get("javax.faces.source");
String behaviorEvent = params.get("javax.faces.behavior.event");
UIComponent source = context.getViewRoot().findComponent(sourceClientId);
List<String> methodExpressions = new ArrayList<>();
if (source instanceof ClientBehaviorHolder && behaviorEvent != null) {
for (ClientBehavior behavior : ((ClientBehaviorHolder) source).getClientBehaviors().get(behaviorEvent)) {
List<BehaviorListener> listeners = getField(BehaviorBase.class, List.class, behavior);
if (listeners != null) {
for (BehaviorListener listener : listeners) {
MethodExpression methodExpression = getField(listener.getClass(), MethodExpression.class, listener);
if (methodExpression != null) {
methodExpressions.add(methodExpression.getExpressionString());
}
}
}
}
}
if (source instanceof ActionSource2) {
MethodExpression methodExpression = ((ActionSource2) source).getActionExpression();
if (methodExpression != null) {
methodExpressions.add(methodExpression.getExpressionString());
}
}
System.out.println(methodExpressions); // Do your thing with it.
}
private static <C, F> F getField(Class<? extends C> classType, Class<F> fieldType, C instance) {
try {
for (Field field : classType.getDeclaredFields()) {
if (field.getType().isAssignableFrom(fieldType)) {
field.setAccessible(true);
return (F) field.get(instance);
}
}
} catch (Exception e) {
// Handle?
}
return null;
}
}
In order to get it to run, register as below in faces-config.xml:
<lifecycle>
<phase-listener>com.example.AjaxActionLoggerPhaseListener</phase-listener>
</lifecycle>
Above is tested and compatible with Mojarra and PrimeFaces and theoretically also compatible with MyFaces.
Update: in case you're using JSF utility library OmniFaces, or are open to, since version 2.4 you can use the new Components#getCurrentActionSource() utility method to find out the current action source component and Components#getActionExpressionsAndListeners() to get a list of all action methods and listeners registered on a given component. This is also useable on regular (non-ajax) requests. With that, the above PhaseListener example can be reduced as below:
public class FacesActionLoggerPhaseListener implements PhaseListener {
#Override
public PhaseId getPhaseId() {
return PhaseId.PROCESS_VALIDATIONS;
}
#Override
public void beforePhase(PhaseEvent event) {
// NOOP.
}
#Override
public void afterPhase(PhaseEvent event) {
if (!event.getFacesContext().isPostback())) {
return;
}
UIComponent source = Components.getCurrentActionSource();
List<String> methodExpressions = Components.getActionExpressionsAndListeners(source);
System.out.println(methodExpressions); // Do your thing with it.
}
}
I am trying to get a function to be called everytime an event occurs. In the KinectRegion class there is an event called HandPointerGrip: http://msdn.microsoft.com/en-us/library/microsoft.kinect.toolkit.controls.kinectregion.handpointergrip.aspx.
I see that it has declared the event and it seems to me that the event has already been set to be invoked(HandPointerEventArgs)? How do I attach a function to this event?
public Menu()
{
KinectRegion.HandPointerGripEvent+=Hand_Gripped; // why doesn't this work? :(
}
private void Hand_Gripped(object sender, HandPointerEvnetArgs e)
{
MessageBox.Show("I work!"); // I wish this would work
}
Been working hard on this problem and here is something I think will work. Afraid to test it. Learning a lot about routed events, delegates, and events.
namespace ...
{
public delegate void HandPointerEventHandler(object sender, HandPointerEventArgs e);
public partial class thePage : Page
{
public event HandPointerEventHandler HandGripped
{
add {this.AddHandler(KinectRegion.HandPointerGripEvent,value);}
remove {this.RemoveHandler(KinectRegion.HandPointerGripEvent,vlaue);}
}
public thePage()
{
InitializeComponent();
this.HandGripped += new HandPointerEventHandler(OnHandGripped);
}
protected virtual void OnHandGripped(object sender, HandPointerEventArgs e)
{
MessageBox.Show("hello"); //hopefully
}
}
}
The first block of code should work fine. My guess is that the HandPointerGripEvent is hooked up ok, it just never fires.
How are you setting up your KinectRegion?
Are you updating the interration library each frame?
Perhaps this helps?
Kinect SDK 1.7: Mapping Joint/Cursor Coordinates to screen Resolution
KinectRegion.AddHandPointerGripHandler(this.Button1, this.Button1_Click);
Here Button1 is:
< k:KinectTileButton x:Name="Button1" Height="150" Width="150" Content="Click"/ >
The namespaces:
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:k="http://schemas.microsoft.com/kinect/2013"
Button1_Click is the method itself, for example:
private void Button1_Click(object sender, RoutedEventArgs e)
{
MessageBox.Show("YOU GOT ME !!!");
}
If you want to add a grip handler for another interface object, you just do:
KinectRegion.AddHandPointerGripHandler(< object name >, < method name >);
And s.o.
This is quite straight forward(ish) to do is the event is 'real' as in now created by DynamicProxy, but I can't work anything out for a mocked event.
The best way to explain what I'm trying to achieve is with code, please see the comment lines in the test method:
using System;
using Moq;
using NUnit.Framework;
namespace MOQTest
{
[TestFixture]
public class EventsMoqTest
{
[Test]
public void DetachTest()
{
var hasEventMock = new Mock<IHasEvent>();
using (var observer = new Observer(hasEventMock.Object))
{
//Assert that hasEventMock.Object has handler attached
}
//Assert that hasEventMock.Object DOES NOT have handler attached
}
}
public interface IHasEvent
{
event EventHandler AnEvent;
}
public class Observer : IDisposable
{
private readonly IHasEvent _hasEvent;
private readonly EventHandler _hasEventOnAnEvent;
public Observer(IHasEvent hasEvent)
{
_hasEvent = hasEvent;
_hasEventOnAnEvent = _hasEvent_AnEvent;
_hasEvent.AnEvent += _hasEventOnAnEvent;
}
void _hasEvent_AnEvent(object sender, EventArgs e)
{}
public void Dispose()
{
_hasEvent.AnEvent -= _hasEventOnAnEvent;
}
}
}
Unfortunately, you can't. This isn't really a moq issue, but the way the C# event keyword works with delegates. See this SO answer for more information.