Notification callback in Velocity CTP3

This is an example of how to make the Notification callback work in Velocity CTP3.

Here is my web.config – the cache is a routing client:

<?xml version=“1.0“?>

<configuration>

<configSections>

<!– required to read the <dataCacheClient> element –>

<section name=“dataCacheClient“

type=“Microsoft.Data.Caching.DataCacheClientSection,CacheBaseLibrary“

allowLocation=“true“

allowDefinition=“Everywhere“/>

<!– required to read the <fabric> element, when present –>

<section name=“fabric“

type=“System.Data.Fabric.Common.ConfigFile,FabricCommon“

allowLocation=“true“

allowDefinition=“Everywhere“/>

<!– routing client–>

<dataCacheClient deployment=“routing“>

<clientNotification pollInterval=“300“ />

<!– cache host(s) –>

<hosts>

<host

name=“VIRTUALB-UJT42H“

cachePort=“22233“

cacheHostName=“DistributedCacheService“/>

</hosts>

</dataCacheClient>

</configuration>

Here is the cache cluster configuration via the command Export-CacheClusterConfig:

<?xml version=“1.0“ encoding=“utf-8“?>

<configuration>

<configSections>

<section name=“dataCache“ type=“Microsoft.Data.Caching.DataCacheSection, CacheBaseLibrary, Version=1.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91“ />

</configSections>

<dataCache cluster=“Velocity_Cluster_1“ size=“Small“>

<caches>

<cache type=“partitioned“ consistency=“strong“ name=“default“>

<policy>

<eviction type=“lru“ />

<expiration defaultTTL=“10“ isExpirable=“true“ />

<serverNotification isEnabled=“true“ />

</policy>

</cache>

<cache type=“partitioned“ consistency=“strong“ name=“default_2“>

<policy>

<eviction type=“lru“ />

<expiration defaultTTL=“10“ isExpirable=“true“ />

<serverNotification isEnabled=“true“ />

</policy>

</cache>

</caches>

<hosts>

<host clusterPort=“22234“ hostId=“1825498580“ size=“1024“ quorumHost=“true“

name=“VIRTUALB-UJT42H“ cacheHostName=“DistributedCacheService“

cachePort=“22233“ />

</hosts>

<advancedProperties>

<partitionStoreConnectionSettings providerName=“System.Data.SqlClient“

connectionString=“Data Source=VIRTUALB-UJT42H\SQLEXPRESS;Initial Catalog=Velocity_Shared_1;User Id=Not_sa;Password=ForYourEyesOnly;“

leadHostManagement=“false“ />

</advancedProperties>

</dataCache>

</configuration>

Here is the code of CacheWorker.cs (kind of helper class with singleton pattern):

using System;

using Microsoft.Data.Caching;

namespace VelocityTest

{

public class CacheWorker

{

private static object _synclock = new object();

private static CacheWorker _cacheWorker = null;

private static DataCacheFactory _cacheFactory = null;

private static DataCache _defaultCache = null;

private CacheWorker()

{

}

public static CacheWorker Instance

{

get

{

lock (_synclock)

{

try

{

if (_cacheWorker == null)

{

_cacheWorker = new CacheWorker();

// we use configuration file

_cacheFactory = new DataCacheFactory();

// default cache

_defaultCache = _cacheFactory.GetDefaultCache();

}

return _cacheWorker;

}

catch (DataCacheException ex)

{

return null;

}

}

}

}

public DataCacheFactory CacheFactory

{

get { return _cacheFactory; }

}

public DataCache DefaultCache

{

get { return _defaultCache; }

}

}

}

Here is the partial code-behind of the test page:

public partial class _Default : System.Web.UI.Page

{

public const string CACHE_KEY = “{8768036E-2B99-4563-8BA5-C2D07B5B6023}”;

protected static DataCacheFactory _factory = CacheWorker.Instance.CacheFactory;

protected static DataCache _cache = CacheWorker.Instance.DefaultCache;

protected void Page_Load(object sender, EventArgs e)

{

if (!Page.IsPostBack)

{

DataCacheOperation filter = DataCacheOperation.AddItem | DataCacheOperation.RemoveItem | DataCacheOperation.ReplaceItem | DataCacheOperation.ClearRegion | DataCacheOperation.CreateRegion | DataCacheOperation.RemoveRegion;

DataCacheNotificationDescriptor dn = _cache.AddCacheLevelCallback(filter, OnCacheNotificationReceived);

SetCache(MyPerson, true);

ShowCache(GetCache());

}

btnUpdate.Click += new EventHandler(btnUpdate_Click);

btnRefresh.Click += new EventHandler(btnRefresh_Click);

btnRemove.Click += new EventHandler(btnRemove_Click);

btnGet.Click += new EventHandler(btnGet_Click);

btnAnotherPage.Click += new EventHandler(btnAnotherPage_Click);

}

// other code is here….

public void OnCacheNotificationReceived(string cacheName, string regionName, string key, DataCacheItemVersion version, DataCacheOperation cacheOperation, DataCacheNotificationDescriptor nd)

{

StringBuilder sb = new StringBuilder();

sb.Append(“cacheName: “ + cacheName + Environment.NewLine);

sb.Append(“regionName: “ + regionName + Environment.NewLine);

sb.Append(“key: “ + key + Environment.NewLine);

sb.Append(“cacheOperation: “ + cacheOperation.ToString() + Environment.NewLine);

txtMessageBox.Text = sb.ToString();

}

}

Basically the configuration has the Notification enabled and set the client as routing client. The callback is fired when ever there is a change in cache item or region.