RedisOutputCacheProvider Serialization broke in version 4.0.1

[DaveSweeton]

We recently updated from version 3.0.1 to version 4.0.1 and output caching broke silently.

After investigating, the issue seems to be in serialization. 3.0.1 used this for serialization:

redisUtility.GetBytesFromObject(entry), which used a custom or BinarySerializer.

In 4.0,1 the code switched to:

System.Web.OutputCache.Serialize(ms, outputCacheEntry);

The problem with using that method is that it whitelists object types that it supports, it is not a general serialization method:

public static void Serialize(Stream stream, object data)
{
  BinaryFormatter binaryFormatter = new BinaryFormatter();
  switch (data)
  {
    case OutputCacheEntry _:
    case PartialCachingCacheEntry _:
    case CachedVary _:
    case ControlCachedVary _:
    case FileResponseElement _:
    case MemoryResponseElement _:
    case SubstitutionResponseElement _:
      binaryFormatter.Serialize(stream, data);
      break;
    default:
      throw new ArgumentException(System.Web.SR.GetString("OutputCacheExtensibility_CantSerializeDeserializeType"));
  }
}

System.Web.Caching.CachedVary is in the allowed list, but Microsoft.AspNet.OutputCache.CachedVary is not (since it's not a dependency).

This means that RedisOutputCacheProvider does not work with Microsoft.AspNet.OutputCache.OutputCacheModuleAsync, which seems like a common use case.

Switching back to internal serialization would fix this issue.