/// <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 = _queuePolicy.TryEnterAsync();
if (waitInQueueTask.IsCompleted)
{
RequestThrottlingEventSource.Log.QueueSkipped();
}
else
{
using (RequestThrottlingEventSource.Log.QueueTimer())
{
await waitInQueueTask;
}
}
if (waitInQueueTask.Result)
{
try
{
await _next(context);
}
finally
{
_queuePolicy.OnExit();
}
}
else
{
RequestThrottlingEventSource.Log.RequestRejected();
RequestThrottlingLog.RequestRejectedQueueFull(_logger);
context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
await _onRejected(context);
}
}
/// <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)
{
Interlocked.Increment(ref _queuedRequests);
var success = false;
try
{
success = await _queuePolicy.TryEnterAsync();
}
finally
{
Interlocked.Decrement(ref _queuedRequests);
}
if (success)
{
try
{
await _next(context);
}
finally
{
_queuePolicy.OnExit();
}
}
else
{
RequestThrottlingLog.RequestRejectedQueueFull(_logger);
context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
await _onRejected(context);
}
}
/// <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.RequestRejectedQueueFull(_logger);
context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
return;
}
else if (!waitInQueueTask.IsCompletedSuccessfully)
{
RequestThrottlingLog.RequestEnqueued(_logger, ActiveRequestCount);
var result = await waitInQueueTask;
RequestThrottlingLog.RequestDequeued(_logger, ActiveRequestCount);
Debug.Assert(result);
}
else
{
RequestThrottlingLog.RequestRunImmediately(_logger, ActiveRequestCount);
}
try
{
await _next(context);
}
finally
{
_requestQueue.Release();
}
}