Updating Unity Mobile Games Without Store Submissions: C# Remote Download & Versioning Pipeline (Part 2)

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.Networking;

public class RemoteAssetManager : MonoBehaviour
{
    private static RemoteAssetManager instance;
    public static RemoteAssetManager Instance => instance;

    [Header("CDN Configuration")]
    [SerializeField] private string cdnBaseUrl = "https://cdn.yourgame.com/AssetBundles/Android/";

    private void Awake()
    {
        if (instance != null && instance != this)
        {
            Destroy(gameObject);
            return;
        }
        instance = this;
        DontDestroyOnLoad(gameObject);
    }

    // =========================================================================
    // DOWNLOAD & CACHE ASSETBUNDLE OVER HTTPS
    // =========================================================================
    public IEnumerator DownloadOrLoadBundle(
        string bundleName, 
        string hashString, 
        uint crc, 
        Action<float> onProgress, 
        Action<AssetBundle> onSuccess, 
        Action<string> onError
    ) {
        string fullUrl = $"{cdnBaseUrl}{bundleName}";
        Hash128 bundleHash = Hash128.Parse(hashString);

        // Check if bundle version is already cached on device
        bool isCached = Caching.IsVersionCached(fullUrl, bundleHash);
        Debug.Log($"[LiveOps] Requesting Bundle '{bundleName}' | Cached: {isCached}");

        using (UnityWebRequest request = UnityWebRequestAssetBundle.GetAssetBundle(fullUrl, bundleHash, crc))
        {
            // Start async request
            UnityWebRequestAsyncOperation operation = request.SendWebRequest();

            while (!operation.isDone)
            {
                // Report download progress (0.0f to 1.0f)
                onProgress?.Invoke(operation.progress);
                yield return null;
            }

            if (request.result != UnityWebRequest.Result.Success)
            {
                string errorMsg = $"[LiveOps Download Error] Failed to fetch '{bundleName}': {request.error}";
                Debug.LogError(errorMsg);
                onError?.Invoke(errorMsg);
            }
            else
            {
                onProgress?.Invoke(1.0f);
                AssetBundle bundle = DownloadHandlerAssetBundle.GetContent(request);
                Debug.Log($"[LiveOps Success] Successfully loaded bundle '{bundleName}'!");
                onSuccess?.Invoke(bundle);
            }
        }
    }
}

public class LevelLoader : MonoBehaviour
{
    public void LoadRemoteLevel(string levelBundleName, string hash, uint crc)
    {
        StartCoroutine(RemoteAssetManager.Instance.DownloadOrLoadBundle(
            levelBundleName,
            hash,
            crc,
            progress => Debug.Log($"Downloading Level... {(progress * 100):F0}%"),
            bundle => {
                // Load level prefab from bundle
                GameObject levelPrefab = bundle.LoadAsset<GameObject>("Level_05_Halloween");
                Instantiate(levelPrefab);

                // Unload bundle compressed header metadata (keep loaded objects)
                bundle.Unload(false);
            },
            error => Debug.LogError(error)
        ));
    }
}