/// <summary>
/// Request that a command should be executed.
/// </summary>
/// <typeparam name="T">Type of command to execute.</typeparam>
/// <param name="command">Command to execute</param>
/// <returns>
/// Task which completes once the command has been delivered (and NOT when it has been executed).
/// </returns>
/// <exception cref="T:System.ArgumentNullException">command</exception>
/// <remarks>
/// <para>
/// The actual execution of an command can be done anywhere at any time. Do not expect the command to be executed
/// just because this method returns. That just means
/// that the command have been successfully delivered (to a queue or another process etc) for execution.
/// </para>
/// </remarks>
public async Task ExecuteAsync <T>(T command) where T : Command
{
using (var scope = _container.CreateScope())
{
if (ScopeCreated != null)
{
var e = new ScopeCreatedEventArgs(scope);
ScopeCreated(this, e);
}
var handlers = scope.ResolveAll <ICommandHandler <T> >().ToList();
if (handlers.Count == 0)
{
throw new CqsHandlerMissingException(typeof(T));
}
if (handlers.Count > 1)
{
throw new OnlyOneHandlerAllowedException(typeof(T));
}
if (GlobalConfiguration.AuthorizationFilter != null)
{
var ctx = new AuthorizationFilterContext(command, handlers);
GlobalConfiguration.AuthorizationFilter.Authorize(ctx);
}
await handlers[0].ExecuteAsync(command);
CommandInvoked(this, new CommandInvokedEventArgs(scope, command));
}
}
/// <summary>
/// Invoke a query and wait for the result
/// </summary>
/// <typeparam name="TResult">Type of result that the query will return</typeparam>
/// <param name="query">Query to execute.</param>
/// <returns>
/// Task which will complete once we've got the result (or something failed, like a query wait timeout).
/// </returns>
/// <exception cref="T:System.ArgumentNullException">query</exception>
public async Task <TResult> QueryAsync <TResult>(Query <TResult> query)
{
var handler = typeof(IQueryHandler <,>).MakeGenericType(query.GetType(), typeof(TResult));
using (var scope = _container.CreateScope())
{
if (ScopeCreated != null)
{
var createdEventArgs = new ScopeCreatedEventArgs(scope);
ScopeCreated(this, createdEventArgs);
}
var handlerList = scope.ResolveAll(handler);
var handlers = handlerList.ToList();
if (handlers.Count == 0)
{
throw new CqsHandlerMissingException(query.GetType());
}
if (handlers.Count != 1)
{
throw new OnlyOneHandlerAllowedException(query.GetType());
}
if (GlobalConfiguration.AuthorizationFilter != null)
{
var ctx = new AuthorizationFilterContext(query, handlers);
GlobalConfiguration.AuthorizationFilter.Authorize(ctx);
}
var method = handler.GetMethod("ExecuteAsync");
try
{
var task = (Task)method.Invoke(handlers[0], new object[] { query });
await task;
var result1 = ((dynamic)task).Result;
if (QueryExecuted != null)
{
QueryExecuted(this, new QueryExecutedEventArgs(scope, query, handlers[0]));
}
return(result1);
}
catch (TargetInvocationException exception)
{
ExceptionDispatchInfo.Capture(exception.InnerException).Throw();
throw new Exception("this will never happen as the line above throws an exception. It's just here to remove a warning");
}
}
}
/// <summary>
/// Invoke a request and wait for the reply
/// </summary>
/// <typeparam name="TReply">Type of reply that we should get for the request.</typeparam>
/// <param name="request">Request that we want a reply for.</param>
/// <returns>
/// Task which will complete once we've got the result (or something failed, like a request wait timeout).
/// </returns>
/// <exception cref="T:System.ArgumentNullException">query</exception>
public async Task <TReply> ExecuteAsync <TReply>(Request <TReply> request)
{
var handler = typeof(IRequestHandler <,>).MakeGenericType(request.GetType(), typeof(TReply));
using (var scope = _container.CreateScope())
{
if (ScopeCreated != null)
{
var e = new ScopeCreatedEventArgs(scope);
ScopeCreated(this, e);
}
var allHandlersAsObjects = scope.ResolveAll(handler);
var handlers = allHandlersAsObjects.ToList();
if (handlers.Count == 0)
{
throw new CqsHandlerMissingException(request.GetType());
}
if (handlers.Count != 1)
{
throw new OnlyOneHandlerAllowedException(request.GetType());
}
if (GlobalConfiguration.AuthorizationFilter != null)
{
var ctx = new AuthorizationFilterContext(request, handlers);
GlobalConfiguration.AuthorizationFilter.Authorize(ctx);
}
try
{
var method = handler.GetMethod("ExecuteAsync");
var task = (Task)method.Invoke(handlers[0], new object[] { request });
await task;
var result = ((dynamic)task).Result;
RequestInvoked(this, new RequestInvokedEventArgs(scope, request));
return(result);
}
catch (TargetInvocationException exception)
{
ExceptionDispatchInfo.Capture(exception.InnerException).Throw();
throw new Exception(
"this will never happen as the line above throws an exception. It's just here to remove a warning");
}
}
}
private async Task InvokeHandlerAsync <TEventType>(Type eventHandlerType, TEventType e,
ICollection <EventHandlerInfo> eventInfo) where TEventType : ApplicationEvent
{
using (var scope = _container.CreateScope())
{
ScopeCreatedEventArgs createdEventArgs = null;
if (ScopeCreated != null)
{
createdEventArgs = new ScopeCreatedEventArgs(scope);
ScopeCreated(this, createdEventArgs);
}
var subscriber = scope.Resolve(eventHandlerType);
var sw = new Stopwatch();
sw.Start();
try
{
await((IApplicationEventSubscriber <TEventType>)subscriber).HandleAsync(e);
eventInfo.Add(new EventHandlerInfo(subscriber.GetType(), sw.ElapsedMilliseconds));
if (ScopeClosing != null)
{
ScopeClosing(this, new ScopeClosingEventArgs(scope)
{
HandlersWasSuccessful = true
});
}
}
catch (Exception ex)
{
eventInfo.Add(new EventHandlerInfo(subscriber.GetType(), sw.ElapsedMilliseconds)
{
Failure = new HandlerFailure(subscriber, ex)
});
if (ScopeClosing != null)
{
ScopeClosing(this, new ScopeClosingEventArgs(scope)
{
HandlersWasSuccessful = false
});
}
throw;
}
}
}
/// <summary>
/// Publish a new application event.
/// </summary>
/// <typeparam name="TApplicationEvent">Type of event to publish.</typeparam>
/// <param name="e">Event to publish, must be serializable.</param>
/// <returns>
/// Task triggered once the event has been delivered.
/// </returns>
public async Task PublishAsync <TApplicationEvent>(TApplicationEvent e)
where TApplicationEvent : ApplicationEvent
{
using (var scope = _container.CreateScope())
{
ScopeCreatedEventArgs createdEventArgs = null;
if (ScopeCreated != null)
{
createdEventArgs = new ScopeCreatedEventArgs(scope);
ScopeCreated(this, createdEventArgs);
}
var implementations = scope
.ResolveAll <IApplicationEventSubscriber <TApplicationEvent> >()
.ToList();
if (GlobalConfiguration.AuthorizationFilter != null)
{
var ctx = new AuthorizationFilterContext(e, implementations);
GlobalConfiguration.AuthorizationFilter.Authorize(ctx);
}
var eventInfo = new List <EventHandlerInfo>();
var tasks = implementations.Select(x => PublishEvent(x, e, eventInfo));
Task task = null;
try
{
task = Task.WhenAll(tasks);
await task;
EventPublished(this, new EventPublishedEventArgs(scope, e, true, eventInfo));
}
catch
{
EventPublished(this, new EventPublishedEventArgs(scope, e, false, eventInfo));
var failures = eventInfo.Where(x => x.Failure != null).Select(x => x.Failure).ToList();
HandlerFailed(this, new EventHandlerFailedEventArgs(e, failures, eventInfo.Count));
throw task.Exception;
}
}
}
