public IAsyncEnumerable <StockTickerUpdate> Subscribe(IAsyncEnumerable <SymbolRequest> request, CallContext context)
{
var cancellationToken = CancellationTokenSource.CreateLinkedTokenSource(_cts.Token, context.CancellationToken).Token;
var buffer = Channel.CreateUnbounded <StockTickerUpdate>();
_subscriber = _subscriberFactory.GetSubscriber();
_subscriber.Update += async(sender, args) =>
{
try
{
await buffer.Writer.WriteAsync(new StockTickerUpdate
{
Symbol = args.Symbol,
Price = args.Price,
Time = DateTime.UtcNow
});
}
catch (Exception e)
{
_logger.LogError($"Failed to write message: {e.Message}");
}
};
_processRequestTask = ProcessRequests(request, buffer.Writer, cancellationToken);
return(buffer.AsAsyncEnumerable(cancellationToken));
}
private async Task HandleActions(IAsyncStreamReader <ActionMessage> requestStream, IFullStockPriceSubscriber subscriber, CancellationToken token)
{
await foreach (var action in requestStream.ReadAllAsync(token))
{
switch (action.ActionCase)
{
case ActionMessage.ActionOneofCase.None:
_logger.LogWarning("No Action specified.");
break;
case ActionMessage.ActionOneofCase.Add:
subscriber.Add(action.Add.Symbol);
break;
case ActionMessage.ActionOneofCase.Remove:
subscriber.Remove(action.Remove.Symbol);
break;
default:
_logger.LogWarning($"Unknown Action '{action.ActionCase}'.");
break;
}
}
}
