Using Read-Through with Cache Operations

This section will explain the use of Read-Through provider after configuring and deploying it. NCache supports multiple Read-Through providers with an application.

NCache provides Alachisoft.NCache.Web.Caching.DSReadOption enum to specify Read thru option in APIs.

Multiple Read-Through providers can be configured through NCache. Default Read-Through provider will be called if specific provider name is not mentioned through API. You can also use providers other than default by using provider specific overloads of APIs.

To utilize the APIs, include the following namespace in your application:

Alachisoft.NCache.Runtime.DatasourceProviders

Alachisoft.NCache.Web.Caching

Alachisoft.NCache.Runtime

Using Get Method

Member	Description
`Get(string key, DSReadOption dsReadOption)`	Gets item from cache and uses default provider
`Get(string key, string providerName, DSReadOption dsReadOption)`	Gets item from cache and uses specified provider

Product product=null;
try
{
  string key = "Product:1001";
  object data = cache.Get(key, DSReadOption.ReadThru);

  if (data != null)
  {
   product = (Product)data;
  }
}
catch (OperationFailedException exp) {
  //handle exception
}

Using Read-Through with Bulk Operations

For better understanding of the these operations review Bulk Operations.

Member	Description
`IDictionary GetBulk(string[] keys, DSReadOption dsReadOption)`	Gets bulk items from cache and uses default provider
`IDictionary GetBulk(string[] keys, string providerName, DSReadOption dsReadOption)`	Gets bulk items from cache and uses specified provider

try
{
   String[] keys = { "Product:1001", "Product:1002",
   "Product:1003","Product:1004"};

   IDictionary resultSet = cache.GetBulk(keys, DSReadOption.ReadThru);

   //IDictionary contains cached keys and values
}
catch (OperationFailedException exp)
{
  //handle exception
}

Using Read-Through with CacheItem

For this scenario, use the following API.

Member	Description
`CacheItem GetCacheItem(string key DSReadOption dsReadOption)`	Gets `CacheItem` from cache and uses default provider
`GetCacheItem(string key, string providerName, DSReadOption dsReadOption)`	Gets `CacheItem` from cache and uses specified provider

string key = "Product:1001";
Product product=null;
try
{
   CacheItem data = cache.GetCacheItem(key, DSReadOption.ReadThru);

   if (data!= null)
   {
     product = (Product)data.Value;
   }
}
catch (Exception exp)
{
  //handle exception
}

You can specify the default provider through NCache Manager or through client.ncconf file placed in the config folder of the NCache installation directory. If the provider name is not provided in both the API and client.ncconf, the default provider will automatically be used.

<cacheid="mycache" default-readthru-provider="defaultProviderName" client-cache-id="" client-cache-syncmode="optimistic" default-writethru-provider="" load-balance="True">
  ...
</cache>

CacheInitParams can also be used to specify providers. NCache logs errors/exceptions in cache logs in case of an exception during loading the provided assemblies.