public async Task Invoke(HttpContext context)
{
var endpoint = context.GetEndpoint();
RequestLimitAttribute requestLimit = endpoint?.Metadata.GetMetadata <RequestLimitAttribute>();
RequestCount requestCount = null;
try
{
if (requestLimit != null)
{
requestCount = _requestCounts.GetOrAdd(endpoint.DisplayName, (_) => new RequestCount());
int newRequestCount = requestCount.Increment();
if (newRequestCount > requestLimit.MaxConcurrency)
{
_logger.ThrottledEndpoint(requestLimit.MaxConcurrency, newRequestCount);
context.Response.StatusCode = (int)HttpStatusCode.TooManyRequests;
return;
}
}
await _next(context);
}
finally
{
//IMPORTANT This will not work for operation style apis, such as when returning a 202 for egress calls.
requestCount?.Decrement();
}
}
public async Task Invoke(HttpContext context)
{
var endpoint = context.GetEndpoint();
RequestLimitAttribute requestLimit = endpoint?.Metadata.GetMetadata <RequestLimitAttribute>();
IDisposable incrementor = null;
try
{
//Operations and middleware both share the same increment limits, but
//we don't want the middleware to increment the limit if the operation is doing it as well.
if ((requestLimit != null) && !context.Request.Query.ContainsKey(EgressQuery))
{
incrementor = _limitTracker.Increment(requestLimit.LimitKey, out bool allowOperation);
if (!allowOperation)
{
//We should report the same kind of error from Middleware and the Mvc layer.
context.Response.StatusCode = StatusCodes.Status429TooManyRequests;
context.Response.ContentType = ContentTypes.ApplicationProblemJson;
await context.Response.WriteAsync(JsonSerializer.Serialize(new ProblemDetails
{
Status = StatusCodes.Status429TooManyRequests,
Detail = Microsoft.Diagnostics.Monitoring.WebApi.Strings.ErrorMessage_TooManyRequests
}), context.RequestAborted);
return;
}
}
await _next(context);
}
finally
{
incrementor?.Dispose();
}
}
