Creating and using a own CacheDependency in EPiServer

Tore Gjerdrum

Vote:

After reading this thread, http://www.episerver.com/en/EPiServer_Knowledge_Center/Developer-Forum2/EPiServer-Developer-Forums-/1805/6409/, I have started using this cache metod after doing FindPagesWithCriteria searches, and it works very nice. In a project I am working on now we are using a third party plug in to EPiServer called ImageVault(http://www.meridium.se/templates/ProductPage____15.aspx?epslanguage=SV). In some PageTemplates I use a property called an ImageVaultAlbum property. With this i can render out many pictures stored in one album. For each picture in the ImageVault album i create a Image object and insert it into a System.Collection.Generic.List with images, and then render them out with help of a repeater. After the list is filled with Image objects, i thought about caching the list. If there has been no changes in ImageVault, I do not want the list to be generated again. So I then thought of making a CacheDependency based on DateTime.Now.Ticks and set this when changes has been made in ImageVault(by listening to the IVDataFactory.AfterAddFileEvent, IVDataFactory.AfterUpdateFileEvent, IVDataFactory.UpdateAlbumEvent, and IVDataFactory.DeleteFileEvent). The events I listen to fire when they are suppose to and the DateTime.Now.Ticks is updated. But when I insert the list of images in the cache, it is not working. There is no errormessage and when i insert the list in cache using DateTime absoluteExpiration and TimeSpan slidingExpiration, it works fine. So therfore I concluded with that my CacheDependency does not work. Does any one have a clue why this is not working? My code is listed at the end. Is it possible for me to create a VersionKey or a CacheDependency with the EPiServer.DataFactoryCache class? BR, Tore


public const string IVCacheVersionKey = "Moelven.Global.IVCacheVersion";
public static long IVCacheVersion;

protected void Application_Start(Object sender, EventArgs e)
{
   // Init IVCacheVersionKey
   SetIVCacheVersion(null, null);

   // Update ImageVault IVCacheVersionKey
   IVDataFactory.AfterAddFileEvent += SetIVCacheVersion;
   IVDataFactory.AfterUpdateFileEvent += SetIVCacheVersion;
   IVDataFactory.UpdateAlbumEvent += SetIVCacheVersion;
   IVDataFactory.DeleteFileEvent += SetIVCacheVersion;
}

protected static void SetIVCacheVersion(object source, ImageStoreNET.CMS.Data.IVDataEventArgs e)
{
   IVCacheVersion = DateTime.Now.Ticks;
}

// After the List of images is created
string[] dependencyKey = new string[] {Global.IVCacheVersionKey};
CacheDependency dependency = new CacheDependency(null, dependencyKey);
HttpContext.Current.Cache.Insert(key, imageList, dependency);

#16019

Mar 03, 2008 21:43

Steve Celius

Vote:

Can you paste the code where you're inserting an updating the cache item you're adding an dependency to? Or - could this be the error? The dependency should be against another cache item. So, your SetIVCacheVersion method should update the value of an entry in the cache. /Steve

#16823

Mar 08, 2008 13:23

Tore Gjerdrum

Vote:

Hi Steve. My problem was that I did not insert and update the cache item. So now it works perfectly. Thanks for leading my on to the right track :) Is there a reason why the EPiServer.StaticCacheKey is inaccessible for? Had to make my own IVCacheKey that does the same as StaticCacheKey.



private static IVCacheKey _versionKey;
public const string IVCacheVersion = "Moelven.Global.IVCacheVersion";

protected void Application_Start(Object sender, EventArgs e)
{
	// Init _versionKey
	_versionKey = new IVCacheKey("Moelven.Global.IVCacheVersion");
	SetIVCacheVersion(null, null);

	// Update ImageVault _versionKey
	IVDataFactory.AfterAddFileEvent += SetIVCacheVersion;
	IVDataFactory.AfterUpdateFileEvent += SetIVCacheVersion;
	IVDataFactory.UpdateAlbumEvent += SetIVCacheVersion;
	IVDataFactory.DeleteFileEvent += SetIVCacheVersion;
}

protected static void SetIVCacheVersion(object source, ImageStoreNET.CMS.Data.IVDataEventArgs e)
{
	_versionKey.Value = DateTime.Now.Ticks;
}

// Properties
public static long Version
{
	get
	{
		return _versionKey.Value;
	}
}

//Internal class
internal class IVCacheKey
{
	// Fields
	private readonly string _keyName;

	// Methods
	internal IVCacheKey(string keyName)
	{
		_keyName = keyName;
		EnsureKey();
	}

	internal void EnsureKey()
	{
		if (CacheManager.RuntimeCacheGet(_keyName) == null)
		{
			SetKey();
		}
	}

	private void SetKey()
	{
		SetKey(DateTime.Now.Ticks);
	}

	private void SetKey(long value)
	{
		CacheManager.RuntimeCacheInsert(_keyName, value, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable);
	}

	internal void Update()
	{
		CacheManager.RuntimeCacheInsert(_keyName, DateTime.Now.Ticks, null, DateTime.MaxValue, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable);
		UpdateRemoteOnly();
	}

	internal void UpdateRemoteOnly()
	{
		CacheManager.RemoveRemoteOnly(_keyName);
	}

	// Properties
	internal string Name
	{
		get
		{
			return _keyName;
		}
	}

	internal long Value
	{
		get
		{
			EnsureKey();
			return (long)CacheManager.RuntimeCacheGet(_keyName);
		}
		set
		{
			SetKey(value);
		}
	}
}

// After the List of images is created
string[] dependencyKey = new string[] { Global.IVCacheVersion };
CacheDependency dependency = new CacheDependency(null, dependencyKey);
HttpContext.Current.Cache.Insert(key, imageList, dependency);

#16824

Mar 11, 2008 11:07