/// <summary>
/// Invokes the logic of the middleware.
/// </summary>
/// <param name="context">The <see cref="HttpContext"/>.</param>
/// <returns>A <see cref="Task"/> that completes when the request leaves.</returns>
public async Task Invoke(HttpContext context)
{
var waitInQueueTask = _requestQueue.TryEnterQueueAsync();
if (waitInQueueTask.IsCompletedSuccessfully && waitInQueueTask.Result)
{
RequestThrottlingLog.RequestRunImmediately(_logger, ActiveRequestCount);
}
else
{
RequestThrottlingLog.RequestEnqueued(_logger, ActiveRequestCount);
await waitInQueueTask;
RequestThrottlingLog.RequestDequeued(_logger, ActiveRequestCount);
}
if (!waitInQueueTask.Result)
{
RequestThrottlingLog.RequestRejectedQueueFull(_logger);
context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
await _requestThrottlingOptions.OnRejected(context);
return;
}
try
{
await _next(context);
}
finally
{
_requestQueue.Release();
}
}