private QueryHandlerWrapper <TResponse> GetWrappedHandlers <TResponse>(IQueryRequest <TResponse> query)
{
Type[] typeArgs = { query.GetType(), typeof(TResponse) };
var handlerType = typeof(IQueryRequestHandler <,>).MakeGenericType(typeArgs);
var wrapperType = typeof(QueryHandlerWrapper <,>).MakeGenericType(typeArgs);
var handlers =
(IEnumerable)_serviceProvider.GetRequiredService(typeof(IEnumerable <>).MakeGenericType(handlerType));
var wrappedHandlers = (QueryHandlerWrapper <TResponse>)QueryHandlers.GetOrAdd(query.GetType(), handlers.Cast <object>()
.Select(_ => (QueryHandlerWrapper <TResponse>)Activator.CreateInstance(wrapperType)).FirstOrDefault());
return(wrappedHandlers);
}
public TResponse Execute <TResponse>(IQueryRequest <TResponse> request)
where TResponse : IQueryResponse
{
var requestType = request.GetType();
_logger.InfoFormat("Building and executing pipeline for {RequestType}", requestType.Name);
// todo: c# 7 tuples to the rescue pls!
var deconstructMe = ResolveHandler(requestType);
var handlerType = deconstructMe.Item1;
var handler = deconstructMe.Item2;
var requestContext = CreateRequestContext();
handler.Context = requestContext;
var decorators = GetDecorators <TResponse>(handlerType.GetMethod(nameof(IQueryHandler <IQueryRequest <TResponse>, TResponse> .Execute)), requestContext);
_logger.Debug("Begin building pipeline...");
var pipeline = new List <Func <IQueryRequest <TResponse>, TResponse> >
{
r => handler.Execute((dynamic)r)
};
// fallback is doesn't have an incoming pipeline
Func <IQueryRequest <TResponse>, TResponse> fallback = r => handler.Fallback((dynamic)r);
foreach (var decorator in decorators)
{
_logger.DebugFormat("Adding decorator to pipeline: {Decorator}", decorator.GetType().Name);
var next = pipeline.Last();
pipeline.Add(r => decorator.Execute(r, next, fallback));
}
try
{
_logger.DebugFormat("Invoking pipeline...");
return(pipeline.Last().Invoke(request));
}
catch (Exception ex)
{
_logger.InfoException("An exception was thrown during pipeline execution", ex);
throw;
}
}
public async Task <TResponse> ExecuteAsync <TResponse>(IQueryRequest <TResponse> request, CancellationToken cancellationToken = default(CancellationToken))
where TResponse : IQueryResponse
{
var requestType = request.GetType();
_logger.InfoFormat("Building and executing async pipeline for {RequestType}", requestType.Name);
// todo: c# 7 tuples to the rescue pls!
var deconstructMe = ResolveHandler(requestType);
var handlerType = deconstructMe.Item1;
var handler = deconstructMe.Item2;
var requestContext = CreateRequestContext();
handler.Context = requestContext;
var decorators = GetDecorators <TResponse>(handlerType.GetMethod(nameof(IQueryHandler <IQueryRequest <TResponse>, TResponse> .ExecuteAsync)), requestContext);
_logger.Debug("Begin building async pipeline...");
var pipeline = new List <Func <IQueryRequest <TResponse>, CancellationToken, Task <TResponse> > >
{
(r, ct) => handler.ExecuteAsync((dynamic)r, ct)
};
// fallback is doesn't have an incoming pipeline
Func <IQueryRequest <TResponse>, CancellationToken, Task <TResponse> > fallback = (r, ct) => handler.FallbackAsync((dynamic)r, ct);
foreach (var decorator in decorators)
{
_logger.DebugFormat("Adding decorator to async pipeline: {Decorator}", decorator.GetType().Name);
var next = pipeline.Last();
pipeline.Add((r, ct) => decorator.ExecuteAsync(r, next, fallback, ct));
}
try
{
_logger.DebugFormat("Invoking async pipeline...");
return(await pipeline.Last().Invoke(request, cancellationToken).ConfigureAwait(false));
}
catch (Exception ex)
{
_logger.InfoException("An exception was thrown during async pipeline execution", ex);
throw;
}
}
