private void Load()
{
if (!_loaded)
{
try
{
var data = _cache.Get(_sessionKey);
if (data != null)
{
Deserialize(new MemoryStream(data));
}
else if (!_isNewSessionKey)
{
_logger.AccessingExpiredSession(_sessionKey);
}
_isAvailable = true;
}
catch (Exception exception)
{
_logger.SessionCacheReadException(_sessionKey, exception);
_isAvailable = false;
_sessionId = string.Empty;
_sessionIdBytes = null;
_store = new NoOpSessionStore();
}
finally
{
_loaded = true;
}
}
}
/// <summary>
/// Initializes a new instance of <see cref="DistributedSession"/>.
/// </summary>
/// <param name="cache">The <see cref="IDistributedCache"/> used to store the session data.</param>
/// <param name="sessionKey">A unique key used to lookup the session.</param>
/// <param name="idleTimeout">How long the session can be inactive (e.g. not accessed) before it will expire.</param>
/// <param name="ioTimeout">
/// The maximum amount of time <see cref="LoadAsync(CancellationToken)"/> and <see cref="CommitAsync(CancellationToken)"/> are allowed take.
/// </param>
/// <param name="tryEstablishSession">
/// A callback invoked during <see cref="Set(string, byte[])"/> to verify that modifying the session is currently valid.
/// If the callback returns <see langword="false"/>, <see cref="Set(string, byte[])"/> throws an <see cref="InvalidOperationException"/>.
/// <see cref="SessionMiddleware"/> provides a callback that returns <see langword="false"/> if the session was not established
/// prior to sending the response.
/// </param>
/// <param name="loggerFactory">The <see cref="ILoggerFactory"/>.</param>
/// <param name="isNewSessionKey"><see langword="true"/> if establishing a new session; <see langword="false"/> if resuming a session.</param>
public DistributedSession(
IDistributedCache cache,
string sessionKey,
TimeSpan idleTimeout,
TimeSpan ioTimeout,
Func <bool> tryEstablishSession,
ILoggerFactory loggerFactory,
bool isNewSessionKey)
{
if (cache == null)
{
throw new ArgumentNullException(nameof(cache));
}
if (string.IsNullOrEmpty(sessionKey))
{
throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(sessionKey));
}
if (tryEstablishSession == null)
{
throw new ArgumentNullException(nameof(tryEstablishSession));
}
if (loggerFactory == null)
{
throw new ArgumentNullException(nameof(loggerFactory));
}
_cache = cache;
_sessionKey = sessionKey;
_idleTimeout = idleTimeout;
_ioTimeout = ioTimeout;
_tryEstablishSession = tryEstablishSession;
// When using a NoOpSessionStore, using a dictionary as a backing store results in problematic API choices particularly with nullability.
// We instead use a more limited contract - `IDistributedSessionStore` as the backing store that plays better.
_store = new DefaultDistributedSessionStore();
_logger = loggerFactory.CreateLogger <DistributedSession>();
_isNewSessionKey = isNewSessionKey;
}
