/// <summary>
/// 尝试设置 ETag 标签
/// </summary>
/// <param name="cachePolicy"></param>
public bool TrySetETag(ClientCachePolicyBase cachePolicy)
{
if (ETag == null)
{
return(false);
}
cachePolicy.SetETag(ETag);
return(true);
}
/// <summary>
/// 根据缓存项的设置，设置客户端的 maxage 缓存策略
/// </summary>
/// <param name="cachePolicy"></param>
/// <param name="shake"></param>
public void SetMaxAge(ClientCachePolicyBase cachePolicy, TimeSpan shake)
{
var delta = Expiration - DateTime.UtcNow;
if (delta <= TimeSpan.Zero)
{
cachePolicy.SetMaxAge(TimeSpan.Zero);
return;
}
var random = new Random(DateTime.Now.Millisecond);
var offset = TimeSpan.FromMilliseconds(random.NextDouble() * shake.TotalMilliseconds);
var age = delta + offset;
cachePolicy.SetMaxAge(age);
}
/// <summary>
/// 应用客户端缓存策略
/// </summary>
/// <param name="cachePolicy"></param>
public void ApplyClientCachePolicy(ClientCachePolicyBase cachePolicy)
{
TrySetETag(cachePolicy);
SetMaxAge(cachePolicy);
}
/// <summary>
/// 根据缓存项的设置，设置客户端的 maxage 缓存策略
/// </summary>
/// <param name="cachePolicy"></param>
public void SetMaxAge(ClientCachePolicyBase cachePolicy)
{
var shake = Math.Min(DurationWhenCreated.TotalMilliseconds / 50, maxShake.TotalMilliseconds);
SetMaxAge(cachePolicy, TimeSpan.FromMilliseconds(shake));
}