ASP.NET Session State Provider for NCache

Storing ASP.NET sessions in NCache requires no programming. NCache Session State Provider is a custom SessionStateStoreProviderBase implementation for an ASP.NET application. In order to configure and fetch ASP.NET Sessions in your application, the following modifications are required:

Modify Assemblies Tag

Modify <assemblies> section in the application's Web.config and add following assembly.

Enterprise Edition:

<assemblies>
  <add assembly ="Alachisoft.NCache.SessionStoreProvider, Version=x.x.x.x,
Culture=neutral, PublicKeyToken=CFF5926ED6A53769"/>
</assemblies>

Professional and Open Source Edition:

<assemblies>
  <add assembly ="Alachisoft.NCache.SessionStoreProvider, Version=x.x.x.x, Culture=neutral, PublicKeyToken=1448e8d1123e9096"/>
</assemblies>

Note

Replace Version=x.x.x.x with the actual NCache version that you have installed. For example, Version=4.6.0.0.
Refer Alachisoft.NCache.SessionStoreProvider in your project from [InstallDir]/bin/assembly/[2.0 or 4.0] folder.

Modify sessionState Tag

Edit your application's Web.config file and modify the <sessionState> section as given below.

<configuration>
  ...
  <sessionState cookieless="false"
                regenerateExpiredSessionId="true"
                mode="Custom"
                customProvider="NCacheSessionProvider"
                timeout="20">
    <providers>
      <add name="NCacheSessionProvider"
          type="Alachisoft.NCache.Web.SessionState.NSessionStoreProvider"
           cacheName="mySessionCache"
           sessionAppId="NCacheApp"
           exceptionsEnabled="true"
           writeExceptionsToEventLog="false"
           enableLogs="false"
           enableSessionLocking="true"
           sessionLockingRetry="-1"
           emptySessionWhenLocked="false" />       
    </providers>

  </sessionState>
...
</configuration>

Following is the description of different key-value pairs specified above:

Member	Description
`sessionAppId`	Optional `string` attribute. Specifies an identifier to make sure that session ID remains unique in case multiple applications are using the same cache. Application ID should be the same for an application in a web farm. If no app ID is specified, nothing will be concatenated with session ID.
`cacheName`	Required `String` attribute. Specifies the name of the cache to be used for caching session. If no cache name is specified, a configuration exception will be thrown.
`enableSessionLocking`	Optional `Boolean` attribute. If this flag is set, NCache Session Store Provider exclusively locks the session-store item for which multiple concurrent requests are made. The default is `false`.
`sessionLockingRetry`	Optional `Integer` attribute. If `enableSessionLocking` is true and this integer is not less than 0, NCache Session Store Provider will return empty session after `sessionLockingRetry`, which specify the number of retries to acquire a lock. The default is -1.
`writeExceptionsToEventLog`	Optional `Boolean` attribute. If this flag is set, all the exceptions from cache API are written to event logs. The default is `false`.
`enableLogs`	Optional `Boolean` attribute. When this flag is set, store provider logs all error information. The log files are created in `[InstallDir]/log-files/SessionStoreProvider`. The default is `false`.
`enableDetailLogs`	Optional `Boolean` attribute. When this flag is set, store provider logs all debugging information. The log files are created in `[InstallDir]/log-files/SessionStoreProvider`. The default is `false`.
`exceptionsEnabled`	Optional `Boolean` attribute. Specifies whether exceptions from cache API are propagated to the page output. Setting this flag is especially helpful during development phase of application since exceptions provide more information about the specific causes of failure. The default is `false`.
`operationRetry`	It specifies the number of times server will retry the operation, in case connection is lost with a server while an operation is executing. Its default is zero.
`operationRetryInterval`	It specifies the time interval between each operation retry, in case connection is lost with the server. Its default value is zero.

Modify MachineKey Tag

Add <machineKey> entry under <system.web> section. It is required to generate ASP.NET session IDs in the same manner on all nodes. You can use the genmackeys utility available with NCache installation to generate the keys.

<machineKey validationKey ="A01D6E0D1A5D2A22E0854CA612FE5C5EC4AECF24"
   decryptionKey ="ACD8EBF87C4C8937" validation ="SHA1"/>

Fetch Session Data

NCache allows viewing all session data stored in clustered cache via NCache Session State Module. All session data is added in the specified cache as a tagged cache item with tag: NC_ASP.net_session_data.

In order to retrieve previously stored session data, data can be fetched by GetByTag API, which returns Hashtable populated with session IDs and associated session data stored in the cache.

Hashtable allSessionData = cache.GetByTag(new  Alachisoft.NCache.Runtime.Caching.Tag("NC_ASP.net_session_data"));