async Task UpdateProcessingHandler(Update update)
{
UpdateContext pendingUpdateContext = null;
IServiceScope servicesScope = Services.CreateScope();
try
{
var cancellationTokenSource = new CancellationTokenSource();
//Create context.
var updateContext = new UpdateContext(
update,
BotContext,
servicesScope.ServiceProvider,
cancellationTokenSource.Token
);
//Create hidden context.
var hiddenUpdateContext = new HiddenUpdateContext(
cancellationTokenSource,
DateTime.Now,
LoggingAdvancedOptions
);
updateContext.Properties[HiddenUpdateContext.DictKeyName] = hiddenUpdateContext;
_logger.LogTrace("'{0}' created.", updateContext);
//Add to pending list.
_pendingUpdateContexts.Add(
updateContext
);
pendingUpdateContext = updateContext;
//Execute.
await _updateProcessingDelegate.Invoke(updateContext, async() => { });
}
finally
{
//Remove from pending list.
if (pendingUpdateContext != null)
{
pendingUpdateContext.Dispose();
_pendingUpdateContexts.TryRemove(pendingUpdateContext);
_logger.LogTrace("'{0}' disposed and removed from pending.", pendingUpdateContext);
}
servicesScope.Dispose();
}
}
public UpdateProcessingDelegate Build()
{
//For each new iteration and each middleware from stack processingDelegate_OfIteration will contain delegate to execute
//all next middleware.
//"next" delegate for current iteration. Started with empty delegate for last middleware.
UpdateProcessingDelegate processingDelegate_OfIteration = async(UpdateContext ctx, Func <Task> nextFunc) => { };
while (_updateProcessingDelegates.Count > 0)
{
var prevProcessingDelegate = processingDelegate_OfIteration;
var currentProcessingDelegate = _updateProcessingDelegates.Pop();
processingDelegate_OfIteration = async(UpdateContext ctx, Func <Task> mostNext) =>
{
Func <Task> next = async() =>
{
await prevProcessingDelegate.Invoke(ctx, mostNext);
};
//Force exit.
if (ctx.ForceExitRequested)
{
return;
}
//Execute current.
await currentProcessingDelegate.Invoke(ctx, next);
};
}
//Just add some checks.
UpdateProcessingDelegate res = async(UpdateContext ctx, Func <Task> next) =>
{
if (ctx == null)
{
throw new ArgumentNullException(nameof(ctx), "Null context passed to UpdateProcessingDelegate.");
}
if (next == null)
{
throw new ArgumentNullException(nameof(next), "Null 'next' passed to UpdateProcessingDelegate.");
}
await processingDelegate_OfIteration.Invoke(ctx, next);
};
return(res);
}
