Session 共享（Custom模式）By Memcached（原创）

<machineKey decryptionKey="FD69B2EB9A11E3063518F1932E314E4AA1577BF0B824F369" validationKey="5F32295C31223A362286DD5777916FCD0FD2A8EF882783FD3E29AB1FCDFE931F8FA45A8E468B7A40269E50A748778CBB8DB2262D44A86BBCEA96DCA46CBC05C3" validation="SHA1" decryption="Auto"/>
<sessionState mode="Custom" customProvider="SessionProvider" timeout="120">
<providers>
<add name="SessionProvider" type="Entity.MemcachedSessionProvider, Entity" />
</providers>
</sessionState>

<httpModules>
<add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add name="CrossDomainCookieModule" type="Entity.SessionProviderHttpModule, Entity"/>
</httpModules>

public class MemcachedSessionProvider : SessionStateStoreProviderBase
{
private IMemcacheBiz _Client;
private static readonly int _DefaultSessionExpireMinute = 20;
private int _timeout;

public MemcachedSessionProvider()
{
_Client = new MemcacheBiz();
}

public override void Initialize(string name, System.Collections.Specialized.NameValueCollection config)
{
string applicationVirtualPath = System.Web.Hosting.HostingEnvironment.ApplicationVirtualPath;
Configuration webconfig = WebConfigurationManager.OpenWebConfiguration(applicationVirtualPath);
SessionStateSection _objConfig = (SessionStateSection)webconfig.GetSection("system.web/sessionState");

if (_objConfig == null || _objConfig.Timeout == null || _objConfig.Timeout.Minutes <= 0)
{
this._timeout = _DefaultSessionExpireMinute;
}
else
{
this._timeout = _objConfig.Timeout.Minutes;
}
}

public override void InitializeRequest(HttpContext context)
{
//throw new NotImplementedException();
}

public override SessionStateStoreData CreateNewStoreData(HttpContext context, int timeout)
{
return new SessionStateStoreData(new SessionStateItemCollection(),
SessionStateUtility.GetSessionStaticObjects(context), timeout);
}

public override void CreateUninitializedItem(HttpContext context, string id, int timeout)
{
MemcachedSessionObject sessionObject
= new MemcachedSessionObject
{
Content = null,
Locked = false,
SetTime = DateTime.Now,
LockId = 0,
ActionFlag = 1
};
_Client.Set(id, sessionObject, TimeSpan.FromMinutes(timeout));
}

public override void Dispose()
{
//throw new NotImplementedException();
}

public override void EndRequest(HttpContext context)
{
//throw new NotImplementedException();
}

public override SessionStateStoreData GetItem(HttpContext context, string id, out bool locked,
out TimeSpan lockAge, out object lockId, out SessionStateActions actions)
{
SessionStateStoreData sessionStateStoreData = null;
MemcachedSessionObject memcachedSessionObject = null;
DateTime setTime = DateTime.Now;

lockAge = TimeSpan.Zero;
lockId = null;
locked = false;
actions = SessionStateActions.None;
memcachedSessionObject = _Client.Get(id) as MemcachedSessionObject;

if (memcachedSessionObject != null)
{
//如果已经锁定
if (memcachedSessionObject.Locked)
{
lockAge = memcachedSessionObject.LockAge;
lockId = memcachedSessionObject.LockId;
locked = memcachedSessionObject.Locked;
actions = (SessionStateActions)memcachedSessionObject.ActionFlag;
return sessionStateStoreData;
}

memcachedSessionObject.LockId++;
memcachedSessionObject.SetTime = setTime;

_Client.Set(id, memcachedSessionObject);

actions = (SessionStateActions)memcachedSessionObject.ActionFlag;
lockId = memcachedSessionObject.LockId;
lockAge = memcachedSessionObject.LockAge;

if (actions == SessionStateActions.InitializeItem)
sessionStateStoreData = this.CreateNewStoreData(context, _timeout);
else
sessionStateStoreData = this.Deserialize(context, memcachedSessionObject.Content, _timeout);

return sessionStateStoreData;
}

return sessionStateStoreData;
}

public override SessionStateStoreData GetItemExclusive(HttpContext context, string id, out bool locked,
out TimeSpan lockAge, out object lockId, out SessionStateActions actions)
{
return GetItem(context, id, out locked, out lockAge, out lockId, out actions);
}

public override void ReleaseItemExclusive(HttpContext context, string id, object lockId)
{
MemcachedSessionObject memcachedSessionObject = _Client.Get(id) as MemcachedSessionObject;
if (memcachedSessionObject != null)
{
memcachedSessionObject.Locked = false;
memcachedSessionObject.LockId = (Int32)lockId;
_Client.Set(id, memcachedSessionObject, TimeSpan.FromMinutes(_timeout));
}
}

public override void RemoveItem(HttpContext context, string id, object lockId, SessionStateStoreData item)
{
_Client.Delete(id);
}

public override void ResetItemTimeout(HttpContext context, string id)
{
object obj = _Client.Get(id);
if (obj != null)
{
_Client.Set(id, obj, TimeSpan.FromMinutes(_timeout));
}
}

public override void SetAndReleaseItemExclusive(HttpContext context, string id, SessionStateStoreData item, object lockId, bool newItem)
{
DateTime setTime = DateTime.Now;
byte[] bytes = this.Serialize((SessionStateItemCollection)item.Items);
MemcachedSessionObject memcachedSessionObject = new MemcachedSessionObject
{
LockId = 0,
Locked = false,
Content = bytes,
ActionFlag = 0,
SetTime = setTime
};
_Client.Set(id, memcachedSessionObject, TimeSpan.FromMinutes(item.Timeout));
}

public override bool SetItemExpireCallback(SessionStateItemExpireCallback expireCallback)
{
return false;
}

private SessionStateStoreData Deserialize(HttpContext context, byte[] bytes, int timeout)
{
MemoryStream stream = new MemoryStream(bytes);
SessionStateItemCollection collection = new SessionStateItemCollection();

if (stream.Length > 0)
{
BinaryReader reader = new BinaryReader(stream);
collection = SessionStateItemCollection.Deserialize(reader);
}

return new SessionStateStoreData(collection, SessionStateUtility.GetSessionStaticObjects(context), timeout);
}

private byte[] Serialize(SessionStateItemCollection items)
{
MemoryStream ms = new MemoryStream();
BinaryWriter writer = new BinaryWriter(ms);

if (items != null)
items.Serialize(writer);

writer.Close();

return ms.ToArray();
}
}