/// <inheritdoc />
public async Task Invoke(HttpContext httpContext)
{
var strategy = await _strategyProvider?.GetThrottleStrategyAsync(httpContext, null, null);
if (strategy == null)
{
_logger.LogDebug("No strategy for current request.");
await _next(httpContext);
return;
}
var throttleContext = await _throttleService.EvaluateAsync(httpContext, strategy);
if (throttleContext.HasAborted)
{
_logger.LogDebug("Throttling aborted. No throttling applied.");
await _next(httpContext);
return;
}
var response = httpContext.Response;
if (_options.SendThrottleHeaders)
{
foreach (var header in throttleContext.ResponseHeaders.OrderBy(h => h.Key))
{
response.Headers[header.Key] = header.Value;
}
}
if (throttleContext.HasTooManyRequest)
{
_logger.LogInformation("Throttling applied.");
string retryAfter = RetryAfterHelper.GetRetryAfterValue(_clock, _options.RetryAfterMode, throttleContext.RetryAfter);
response.StatusCode = Constants.Status429TooManyRequests;
// rfc6585 section 4 : Responses with the 429 status code MUST NOT be stored by a cache.
response.Headers.SetCommaSeparatedValues("Cache-Control", "no-store", "no-cache");
response.Headers["Pragma"] = "no-cache";
// rfc6585 section 4 : The response [...] MAY include a Retry-After header indicating how long to wait before making a new request.
if (retryAfter != null)
{
response.Headers["Retry-After"] = retryAfter;
}
}
else
{
_logger.LogDebug("No throttling applied.");
await _next(httpContext);
}
await _throttleService.PostEvaluateAsync(throttleContext);
}
public async Task OnResultExecutionAsync(ResultExecutingContext context, ResultExecutionDelegate next)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (next == null)
{
throw new ArgumentNullException(nameof(next));
}
if (!context.Cancel)
{
var resultExecutedContext = await next();
if (_throttleContext != null)
{
await _throttleService.PostEvaluateAsync(_throttleContext);
}
}
}