static IEnumerable <string> CacheVisibility(CacheProxyAttribute proxy, CacheClientAttribute client)
{
if (proxy == null && client == null)
{
yield break;
}
switch (proxy?.Level)
{
case CacheLevel.Everything:
yield return("public");
break;
case CacheLevel.DoNotCache when client?.Level == CacheLevel.DoNotCache:
yield return("no-cache");
break;
case null when client.Level != CacheLevel.DoNotCache:
case CacheLevel.DoNotCache when client?.Level != CacheLevel.DoNotCache:
yield return("private");
break;
}
}
static IEnumerable <string> CacheMaxAge(CacheProxyAttribute proxy, CacheClientAttribute client)
{
TimeSpan proxyAge = TimeSpan.MinValue, browserAge = TimeSpan.MinValue;
if (proxy?.MaxAge != null)
{
TimeSpan.TryParse(proxy.MaxAge, out proxyAge);
}
if (client?.MaxAge != null)
{
TimeSpan.TryParse(client.MaxAge, out browserAge);
}
if (proxyAge == TimeSpan.MinValue && browserAge == TimeSpan.MinValue)
{
yield break;
}
if (proxyAge != TimeSpan.MinValue && browserAge != TimeSpan.MinValue)
{
yield return("s-max-age=" + proxyAge.TotalSeconds);
}
yield return("max-age=" + (proxyAge != TimeSpan.MinValue
? proxyAge.TotalSeconds
: browserAge.TotalSeconds));
}
protected void given_attribute(
CacheClientAttribute client = null,
CacheProxyAttribute proxy = null)
{
this.client = client;
_proxy = proxy;
}
static IEnumerable <string> CacheRevalidation(CacheProxyAttribute proxy, CacheClientAttribute client)
{
if (proxy?.MustRevalidateWhenStale == true && client?.MustRevalidateWhenStale == false)
{
yield return("proxy-revalidate");
}
if (proxy?.MustRevalidateWhenStale == true || proxy?.MustRevalidateWhenStale == true)
{
yield return("must-revalidate");
}
}
// TODO: Reduce all those horrible enumerator allocations!
public static ResponseCachingState GetResponseDirective(
CacheProxyAttribute proxy = null,
CacheClientAttribute client = null)
{
ValidateProxyAttribute(proxy);
var instructions =
CacheVisibility(proxy, client)
.Concat(CacheRevalidation(proxy, client))
.Concat(CacheMaxAge(proxy, client));
return(new ResponseCachingState(instructions));
}
public Func <IOperationAsync, Task <IEnumerable <OutputMember> > > Compose(
Func <IOperationAsync, Task <IEnumerable <OutputMember> > > next)
{
return(async operation =>
{
var outputMembers = await next(operation);
_proxy = operation.FindAttribute <CacheProxyAttribute>();
_client = operation.FindAttribute <CacheClientAttribute>();
_data[CacheKeys.ResponseCache] = CacheResponse.GetResponseDirective(_proxy, _client);
return outputMembers;
});
}
