/// <summary>
/// OnEvent is called whenever the event stream yields a payload and triggers an
/// execution of the subscription query.
/// </summary>
/// <param name="payload">
/// The event stream payload.
/// </param>
/// <returns>
/// Returns a query result which will be enqueued to the response stream.
/// </returns>
private async Task <IQueryResult> OnEvent(object payload)
{
using IDisposable es = _diagnosticEvents.OnSubscriptionEvent(new(this, payload));
using IServiceScope serviceScope = _requestContext.Services.CreateScope();
OperationContext operationContext = _operationContextPool.Get();
try
{
var eventServices = serviceScope.ServiceProvider;
var dispatcher = eventServices.GetRequiredService <IBatchDispatcher>();
// we store the event payload on the scoped context so that it is accessible
// in the resolvers.
ImmutableDictionary <string, object?> scopedContext =
ImmutableDictionary <string, object?> .Empty
.SetItem(WellKnownContextData.EventMessage, payload);
// next we resolve the subscription instance.
var rootValue = RootValueResolver.Resolve(
_requestContext,
eventServices,
_subscriptionType,
ref _cachedRootValue);
// last we initialize a standard operation context to execute
// the subscription query with the standard query executor.
operationContext.Initialize(
_requestContext,
eventServices,
dispatcher,
_requestContext.Operation !,
_queryPlan,
_requestContext.Variables !,
rootValue,
_resolveQueryRootValue);
operationContext.Result.SetContextData(
WellKnownContextData.EventMessage,
payload);
IQueryResult result = await _queryExecutor
.ExecuteAsync(operationContext, scopedContext)
.ConfigureAwait(false);
_diagnosticEvents.SubscriptionEventResult(new(this, payload), result);
return(result);
}
catch (Exception ex)
{
_diagnosticEvents.SubscriptionEventError(new(this, payload), ex);
throw;
}
finally
{
_operationContextPool.Return(operationContext);
}
}
private async Task <IQueryResult> OnEvent(object payload)
{
using IServiceScope serviceScope = _requestContext.Services.CreateScope();
IServiceProvider eventServices = serviceScope.ServiceProvider;
IBatchDispatcher dispatcher = eventServices.GetRequiredService <IBatchDispatcher>();
OperationContext operationContext = _operationContextPool.Get();
try
{
ImmutableDictionary <string, object?> scopedContext =
ImmutableDictionary <string, object?> .Empty
.SetItem(WellKnownContextData.EventMessage, payload);
object?rootValue = RootValueResolver.Resolve(
_requestContext,
eventServices,
_subscriptionType,
ref _cachedRootValue);
operationContext.Initialize(
_requestContext,
eventServices,
dispatcher,
_requestContext.Operation !,
_requestContext.Variables !,
rootValue,
_resolveQueryRootValue);
return(await _queryExecutor
.ExecuteAsync(operationContext, scopedContext)
.ConfigureAwait(false));
}
finally
{
_operationContextPool.Return(operationContext);
}
}