How do I delete AssetBundles from the cache?

Daniel Robledo

July 09, 2021 18:15
Updated

Symptoms

I want to update or remove an old version of my AssetBundles.

Cause

There may be problems with the downloaded AssetBundles.
You want to free space by deleting unused/old AssetBundles.

Resolution

Solution #1:

Use Caching.ClearCache() to delete all AssetBundles that have been cached by the current application.

Caching.ClearCache() returns a bool depending if it was able to complete the operation or not:

public static void ClearCache ()
{
   if (Caching.ClearCache()) 
   {
      Debug.Log("Successfully cleaned the cache");
   }
   else 
   {
      Debug.Log("Cache is being used");
   }
}

If you desire to delete a specific AssetBundle version instead of the entire cache, you can use Caching.ClearCachedVersion()
If you desire to keep one version and delete all others of a specific AssetBundle, you can use Caching.ClearOtherCachedVersions()

Solution #2:

Use Cache.expirationDelay to set the number of seconds that an AssetBundle may remain unused in the cache before it is automatically deleted. When a bundle is downloaded, the timestamp is stored for that given bundle.

To set the expirationDelay property, there needs to be an entry for your application in the Cache folder. That setting is stored in a file in your applications's root Cache folder. If the folder for your application does not exist, the file cannot be written. For that entry to exist you need to first request a bundle. So in order to set the expirationDelay, first request at least one bundle which will create the folder for your app's bundles. You could use any bundle just to make sure the folder exists before you call that property.

Both solutions can be used individually, or at the same time.

More Information

https://docs.unity3d.com/ScriptReference/Caching.html
https://docs.unity3d.com/ScriptReference/Caching.ClearCache.html
https://docs.unity3d.com/ScriptReference/Caching.ClearCachedVersion.html
https://docs.unity3d.com/ScriptReference/Caching.ClearOtherCachedVersions.html
https://docs.unity3d.com/ScriptReference/Cache-expirationDelay.html

Comments

2 comments

Abhay Raghuwanshi

March 12, 2018 06:33
Hello,

We have a game in the market and we have been using WWW.LoadFromCacheOrDownload to download our asset bundles. Now the application data size is growing and we want to control it like the asset bundles not used since X time, should gets automatically deleted, so we tried to set Caching.expirationDelay (for testing we set it to 2 hours but we want it to 7 days in production), but Caching.expirationDelay seems not working at all.
1. It doesn't remove the asset bundle older than Caching.expirationDelay time set by us.
2. When we check the value of Caching.expirationDelay after each app restart, it always stays at "12960000"

We want to clear out old assets (not used since 7 days) and also want to apply the same caching timeout for future assets. Can you suggest whats wrong being done by us!

We are using unity 5.3.4p1
And tested on Android phone and unity ediror.
0

Urs Clement

August 24, 2018 08:30

Shouldn't it be Caching.ClearCache() ?

public static void CleanCache ()
{
   if (Caching.ClearCache ()) 
   {
      Debug.Log("Successfully cleaned the cache.");
   }
   else 
   {
      Debug.Log("Cache is being used.");
   }
}

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