ASP.NET Session State Provider Properties

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:

Prerequisites

To utilize Session State Provider in your application:

Install the AspNet.SessionState.NCache Enterprise/Professional/OpenSource NuGet package to your application by executing the following command in the Package Manager Console:
For Enterprise:

Install-Package AspNet.SessionState.NCache

For Professional:

Install-Package AspNet.SessionState.NCache.Professional

For OpenSource:

Install-Package AspNet.SessionState.NCache.OpenSource

To utilize the provider, include the Alachisoft.NCache.SessionStoreProvider namespaces in your application's Startup.cs.

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="demoClusteredCache"
           sessionAppId="demoApp"
           exceptionsEnabled="true"
           writeExceptionsToEventLog="false"
           enableLogs="false"
           enableSessionLocking="true"
           sessionLockingRetry="-1"
           emptySessionWhenLocked="false" />       
    </providers>

  </sessionState>
...
</configuration>

Modify MachineKey Tag for Web Farms

In case of web farms, add <machineKey> entry under <system.web> section. It is required to generate ASP.NET session IDs in the same manner on all nodes.

Learn about how to generate a machine-key for a web farm:
Generate a Machine Key for a Web Farm (IIS 7)

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

Serializing Session Objects

Before you start using NCache to store and retrieve your ASP.NET session objects, you need to know that you can't store these objects inside the cache directly. To store these session objects inside the cache, you need to serialize them first. There are different methods you can adopt to serialize your session objects. These methods are as follows:

Binary Serialization

You can use this serialization method if you have access to the source code of the application. In this case, you have to mark all the objects (the ones you want to store inside the cache) serializable. But, this method is obsolete as of .NET 6.0.

NCache Compact Serialization

If you can't or don't want to use binary serialization, you can use NCahce Compact Serialization to serialize your session objects. The main benefits of doing so are that this method is faster and only requires to modify your configuration files instead of modifying the source code.

The only problem with this method is that the configuration change can be a big one if the number of classes that you want to serialize is too many.

JSON Serialization

If either of the above-mentioned serialization techniques don't do the job for you, then you can opt for JSON serialization instead. The best part about this method is that it's super fast and simple as it only requires you to make a single change to your web.config file, and the rest of the job is done by NCache automatically at runtime.

You just have to set the value of the usejsonserialization flag as true. By default, the value of this flag is false.

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 a dictionary populated with session IDs and associated session data stored in the cache.

var allSessionData = cache.SearchService.GetByTag(new Tag("NC_ASP.net_session_data"));

SessionState Properties

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 `%NCHOME%/log-files/SessionStoreProvider` (Windows) or `\opt\ncache\log-files\SessionStoreProvider` (Linux). 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 `%NCHOME%/log-files/SessionStoreProvider` (Windows) or `\opt\ncache\log-files\SessionStoreProvider` (Linux). 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 `0`(zero).
`operationRetryInterval`	It specifies the time interval between each operation retry, in case connection is lost with the server. Its default value is `0`(zero).
`usejsonserialization`	This is a boolean attribute. If you want to use JSON serialization for your ASP.NET session objects, set the value of this attribute as `true`. By default, the value of this flag is `false`.