public static void UseHostedWhitelist(
this IApplicationBuilder app,
string url,
HttpClient client = null)
{
// Shared HTTP client for all requests
if (client == null)
{
// Use IMemoryCache from DI if available, e.g. if configured
// with services.AddMemoryCache()
var cache = (MemoryCache)app.ApplicationServices
.GetService(typeof(IMemoryCache))
?? new MemoryCache(new MemoryCacheOptions());
// Default to 5 minutes caching if not forbidden by NoStore
// or specified by Cache-Control headers.
var handler = new CachingHttpHandler(
new HttpClientHandler(), cache);
handler.DefaultCacheDuration = new TimeSpan(0, 5, 0);
client = new HttpClient(handler);
}
// GetStringAsync is called on every IP check, but HttpClient
// will honour caching headers
app.UseWhitelist(async() =>
Whitelist.Parse(await client.GetStringAsync(url)));
}
public void Init(HttpApplication context)
{
var handler = new CachingHttpHandler(
new HttpClientHandler(),
new MemoryCache(new MemoryCacheOptions()));
if (TimeSpan.TryParse(
ConfigurationManager.AppSettings["whitelist:DefaultCacheDuration"],
out var duration))
{
handler.DefaultCacheDuration = duration;
}
_client = new HttpClient(handler);
_url = ConfigurationManager.AppSettings["whitelist:Url"];
var eventHandler = new EventHandlerTaskAsyncHelper(beginRequest);
context.AddOnBeginRequestAsync(
eventHandler.BeginEventHandler,
eventHandler.EndEventHandler);
}