HttpRequestCachePolicy.cs

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using System.Globalization;
 
namespace System.Net.Cache;
 
public class HttpRequestCachePolicy : RequestCachePolicy
{
    private readonly DateTime _lastSyncDateUtc = DateTime.MinValue;
 
    private readonly TimeSpan _maxAge = TimeSpan.MaxValue;
 
    private readonly TimeSpan _minFresh = TimeSpan.MinValue;
 
    private readonly TimeSpan _maxStale = TimeSpan.MinValue;
 
    public new HttpRequestCacheLevel Level { get; }
 
    public DateTime CacheSyncDate
    {
        get
        {
            if (!(_lastSyncDateUtc == DateTime.MinValue) && !(_lastSyncDateUtc == DateTime.MaxValue))
            {
                return _lastSyncDateUtc.ToLocalTime();
            }
            return _lastSyncDateUtc;
        }
    }
 
    public TimeSpan MaxAge => _maxAge;
 
    public TimeSpan MinFresh => _minFresh;
 
    public TimeSpan MaxStale => _maxStale;
 
    public HttpRequestCachePolicy()
        : this(HttpRequestCacheLevel.Default)
    {
    }
 
    public HttpRequestCachePolicy(HttpRequestCacheLevel level)
        : base(MapLevel(level))
    {
        Level = level;
    }
 
    public HttpRequestCachePolicy(HttpCacheAgeControl cacheAgeControl, TimeSpan ageOrFreshOrStale)
        : this(HttpRequestCacheLevel.Default)
    {
        switch (cacheAgeControl)
        {
        case HttpCacheAgeControl.MinFresh:
            _minFresh = ageOrFreshOrStale;
            break;
        case HttpCacheAgeControl.MaxAge:
            _maxAge = ageOrFreshOrStale;
            break;
        case HttpCacheAgeControl.MaxStale:
            _maxStale = ageOrFreshOrStale;
            break;
        default:
            throw new ArgumentException(System.SR.Format(System.SR.net_invalid_enum, "HttpCacheAgeControl"), "cacheAgeControl");
        }
    }
 
    public HttpRequestCachePolicy(HttpCacheAgeControl cacheAgeControl, TimeSpan maxAge, TimeSpan freshOrStale)
        : this(HttpRequestCacheLevel.Default)
    {
        switch (cacheAgeControl)
        {
        case HttpCacheAgeControl.MinFresh:
            _minFresh = freshOrStale;
            break;
        case HttpCacheAgeControl.MaxAge:
            _maxAge = maxAge;
            break;
        case HttpCacheAgeControl.MaxStale:
            _maxStale = freshOrStale;
            break;
        case HttpCacheAgeControl.MaxAgeAndMinFresh:
            _maxAge = maxAge;
            _minFresh = freshOrStale;
            break;
        case HttpCacheAgeControl.MaxAgeAndMaxStale:
            _maxAge = maxAge;
            _maxStale = freshOrStale;
            break;
        default:
            throw new ArgumentException(System.SR.Format(System.SR.net_invalid_enum, "HttpCacheAgeControl"), "cacheAgeControl");
        }
    }
 
    public HttpRequestCachePolicy(DateTime cacheSyncDate)
        : this(HttpRequestCacheLevel.Default)
    {
        _lastSyncDateUtc = cacheSyncDate.ToUniversalTime();
    }
 
    public HttpRequestCachePolicy(HttpCacheAgeControl cacheAgeControl, TimeSpan maxAge, TimeSpan freshOrStale, DateTime cacheSyncDate)
        : this(cacheAgeControl, maxAge, freshOrStale)
    {
        _lastSyncDateUtc = cacheSyncDate.ToUniversalTime();
    }
 
    public override string ToString()
    {
        return "Level:" + Level.ToString() + ((_maxAge == TimeSpan.MaxValue) ? string.Empty : (" MaxAge:" + _maxAge)) + ((_minFresh == TimeSpan.MinValue) ? string.Empty : (" MinFresh:" + _minFresh)) + ((_maxStale == TimeSpan.MinValue) ? string.Empty : (" MaxStale:" + _maxStale)) + ((CacheSyncDate == DateTime.MinValue) ? string.Empty : (" CacheSyncDate:" + CacheSyncDate.ToString(CultureInfo.CurrentCulture)));
    }
 
    private static RequestCacheLevel MapLevel(HttpRequestCacheLevel level)
    {
        if (level <= HttpRequestCacheLevel.NoCacheNoStore)
        {
            return (RequestCacheLevel)level;
        }
        return level switch
        {
            HttpRequestCacheLevel.CacheOrNextCacheOnly => RequestCacheLevel.CacheOnly, 
            HttpRequestCacheLevel.Refresh => RequestCacheLevel.Reload, 
            _ => throw new ArgumentOutOfRangeException("level"), 
        };
    }
}