Loading AssetBundle from Streaming Assets to Cache via UnityWebRequestAssetBundle

Hi Everyone,
I have implemented logic for loading Assetbundles from Cache based on the Directory names (if directory "myBundle" has 0 directories inside - it is empty, otherwise you safely load "myBundle" with UnityWebRequestAssetBundle( "", new CachedAssetBundle{name = "myBundle"}, 0 )) which will load it from Cache (exacly the same directory name as in CachedAssetBundle name ).

The code for loading from Streaming Assets to Cache is like so:

Code (CSharp):

1. private IEnumerator LoadBundlefromStreamingAsset(string pathFromStreamingAssets, string bundleName)
2.         {
3.             string pathToBundle = "file:///" + Application.streamingAssetsPath + "/" + pathFromStreamingAssets;
4.             Log(" Path in Streaming Assets : " + pathToBundle);
5.             using (UnityEngine.Networking.UnityWebRequest request = UnityEngine.Networking.UnityWebRequestAssetBundle.GetAssetBundle(pathToBundle, 0, 0))
6.             {
7.                 request.SendWebRequest();
8.                 yield return request;
9.                 yield return new WaitForSeconds(0.25f);
10.                 AssetBundle bundle = ((UnityEngine.Networking.DownloadHandlerAssetBundle)request.downloadHandler).assetBundle;
11.                 // Remove from memory to allow custom ( based on Caching) logic do its job
12.                 bundle.Unload(true);
13.             }
14. }

Everything works perfectly on Windows and Mac, but when I'm using it on Android, after the first use of the LoadBundlefromStreamingAsset coroutine, using it the second time will result in an error thrown by Unity.

Is there any way around on how to load AssetBundle from StreamingAssets to cache even on Android?

 

It is appeared to be a bug with Caching - when you make a call to ClearAllCache on the Mobile (From the App itself) and then use the above, it all works flawlessly!

 

Did you try loading without "file:///" prefix to the path?
AFAIK Application.streamingAssetsPath already contains it and doubling it might cause issues with caching artifacts resolution.

 

Yes, and yes it was a problem with the file:/// but now, again on Android, I have another Issue :

Code (CSharp):

1.  <Color=Blue>  Loading From Streaming Assets into cache: jar:file:///data/app/com.kau.wrod-1/base.apk!/assets/en/Android/bigdataobject </Color>
2. 01-03 12:13:05.831 10855 10886 I Unity   :
3. 01-03 12:13:05.831 10855 10886 I Unity   : (Filename: ./Runtime/Export/Debug.bindings.h Line: 43)
4. 01-03 12:13:05.831 10855 10886 I Unity   :
5. 01-03 12:13:07.002 10855 10886 E Unity   : InvalidOperationException: Cannot get content from an unfinished UnityWebRequest object
6. 01-03 12:13:07.002 10855 10886 E Unity   :   at UnityEngine.Networking.DownloadHandler.GetCheckedDownloader[T] (UnityEngine.Networking.UnityWebRequest www) [0x0001d] in <6aaad1c9744e454b96e73044b9276939>:0
7. 01-03 12:13:07.002 10855 10886 E Unity   :   at UnityEngine.Networking.DownloadHandlerAssetBundle.GetContent (UnityEngine.Networking.UnityWebRequest www) [0x00001] in <deee6915c84b4f0ea72fc147a614158a>:0
8. 01-03 12:13:07.002 10855 10886 E Unity   :   at KAUGamesLviv.Services.Bundles.BundleScriptable`1+<LoadBundlefromStreamingAsset>c__Iterator0[T].MoveNext () [0x000f1] in <736923169ae449198904e7e23151e2c3>:0

 

Found a mistake :
I have used

Code (CSharp):

1. UnityEngine.Networking.DownloadHandlerAssetBundle.GetContent(request);

to retrieve the content. You should use casting on the attached downloadhandler of the request. This ensures that the content and request are on the same object.

 

Is it? The request itself is exactly the same asyncoperation, isn't it? I currently use both yields, and only when I cast to
((UnityEngine.Networking.DownloadHandlerAssetBundle)request.downloadHandler).assetBundle; the code works without any errors.

 

Got it! thank you!. Also, unrelated shader question, do you know any way on how to retrieve FrameBuffer ? (to use the previous SV_TARGET as a texture, something like a Grabpass, but without the Grabpass)? I have seen how people have made a hack - in first pass use surface shader to write into another texcoord, and in second pass use simple vertex/fragment program to get those texcoord.

 

can anyone help me how to download the images from the server to the streaming assets folder