/// <summary>
/// Starts receiving <see cref="Update"/>s on the ThreadPool, invoking <see cref="IUpdateHandler.HandleUpdate(ITelegramBotClient, Update, CancellationToken)"/> for each.
/// <para>This method will block if awaited. GetUpdates will be called AFTER the <see cref="IUpdateHandler.HandleUpdate(ITelegramBotClient, Update, CancellationToken)"/> returns</para>
/// </summary>
/// <param name="botClient">The <see cref="ITelegramBotClient"/> used for making GetUpdates calls</param>
/// <param name="updateHandler">The <see cref="IUpdateHandler"/> used for processing <see cref="Update"/>s</param>
/// <param name="cancellationToken">The <see cref="CancellationToken"/> with which you can stop receiving</param>
/// <returns></returns>
public static async Task ReceiveAsync(
this ITelegramBotClient botClient,
IUpdateHandler updateHandler,
CancellationToken cancellationToken = default)
{
if (botClient == null)
{
throw new ArgumentNullException(nameof(botClient));
}
if (updateHandler == null)
{
throw new ArgumentNullException(nameof(updateHandler));
}
UpdateType[]? allowedUpdates = updateHandler.AllowedUpdates;
int messageOffset = 0;
var emptyUpdates = new Update[] { };
while (!cancellationToken.IsCancellationRequested)
{
int timeout = (int)botClient.Timeout.TotalSeconds;
var updates = emptyUpdates;
try
{
updates = await botClient.MakeRequestAsync(new GetUpdatesRequest()
{
Offset = messageOffset,
Timeout = timeout,
AllowedUpdates = allowedUpdates,
}, cancellationToken).ConfigureAwait(false);
}
catch (OperationCanceledException)
{
// Ignore
}
catch (Exception ex)
{
await updateHandler.HandleError(botClient, ex, cancellationToken)
.ConfigureAwait(false);
}
foreach (var update in updates)
{
await updateHandler.HandleUpdate(botClient, update, cancellationToken)
.ConfigureAwait(false);
messageOffset = update.Id + 1;
}
}
}