Downloading an AssetBundle from an HTTP server (GET)

To download an AssetBundle from a remote server, you can use UnityWebRequest.AssetBundle. This function streams data into an internal buffer, which decodes and decompresses the AssetBundle’s data on a worker thread.

The function’s arguments take several forms. In its simplest form, it takes only the URL from which the AssetBundle should be downloaded. You may optionally provide a checksum to verify the integrity of the downloaded data.

Alternately, if you wish to use the AssetBundle caching system, you may provide either a version number or a Hash128 data structure. These are identical to the version numbers or Hash128 objects provided to the old system via WWW.LoadFromCacheOrDownload.

Details

• This function creates a UnityWebRequest and sets the target URL to the supplied URL argument. It also sets the HTTP verb to GET, but sets no other flags or custom headers.
• This function attaches a DownloadHandlerAssetBundle to the UnityWebRequest. This download handler has a special assetBundle property, which can be used to extract the AssetBundle once enough data has been downloaded and decoded to permit access to the resources inside the AssetBundle.
• If you supply a version number or Hash128 object as arguments, it also passes those arguments to the DownloadHandlerAssetBundle. The download handler then employs the caching system.

Example

using UnityEngine;
using UnityEngine.Networking;
using System.Collections;
 
public class MyBehaviour : MonoBehaviour {
    void Start() {
        StartCoroutine(GetAssetBundle());
    }
 
    IEnumerator GetAssetBundle() {
        UnityWebRequest www = UnityWebRequest.GetAssetBundle("http://www.my-server.com/myData.unity3d");
        yield return www.Send();
 
        if(www.isError) {
            Debug.Log(www.error);
        }
        else {
            AssetBundle bundle = ((DownloadHandlerAssetBundle)www.downloadHandler).assetBundle;
        }
    }
}

Alternatively, you can implement GetAssetBundle using a helper getter:

    IEnumerator GetTexture() {
        UnityWebRequest www = UnityWebRequest.GetAssetBundle("http://www.my-server.com/myData.unity3d");
        yield return www.Send();

        AssetBundle bundle = DownloadHandlerAssetBundle.GetContent(www);
    }