A durable entity does not deserialize - json.net

Question

I am trying to use a durable entity in my Azure Function to cache some data. However, when I try to retrieve the entity (state) for the first time, I get an exception indicating an issue during the entity deserialization.
Here is my entity class and related code
[JsonObject(MemberSerialization.OptIn)]
public class ActionTargetIdCache : IActionTargetIdCache
{
[JsonProperty("cache")]
public Dictionary<string, ActionTargetIdsCacheItemInfo> Cache { get; set; } = new Dictionary<string, ActionTargetIdsCacheItemInfo>();
public void CacheCleanup(DateTime currentUtcTime)
{
foreach (string officeHolderId in Cache.Keys)
{
TimeSpan cacheItemAge = currentUtcTime - Cache[officeHolderId].lastUpdatedTimeStamp;
if (cacheItemAge > TimeSpan.FromMinutes(2))
{
Cache.Remove(officeHolderId);
}
}
}
public void DeleteActionTargetIds(string officeHolderId)
{
if (this.Cache.ContainsKey(officeHolderId))
{
this.Cache.Remove(officeHolderId);
}
}
public void DeleteState()
{
Entity.Current.DeleteState();
}
public void SetActionTargetIds(ActionTargetIdsCacheEntry entry)
{
this.Cache[entry.Key] = entry.Value;
}
public Task<ActionTargetIdsCacheItemInfo> GetActionTargetIdsAsync(string officeHolderId)
{
if (this.Cache.ContainsKey(officeHolderId))
{
return Task.FromResult(Cache[officeHolderId]);
}
else
{
return Task.FromResult(new ActionTargetIdsCacheItemInfo());
}
}
// public void Reset() => this.CurrentValue = 0;
// public int Get() => this.CurrentValue;
[FunctionName(nameof(ActionTargetIdCache))]
public static Task Run([EntityTrigger] IDurableEntityContext ctx)
=> ctx.DispatchAsync<ActionTargetIdCache>();
}
public class ActionTargetIdsCacheEntry
{
// officeHolderId
public string Key { get; set; } = string.Empty;
public ActionTargetIdsCacheItemInfo Value { get; set; } = new ActionTargetIdsCacheItemInfo();
}
[JsonObject(MemberSerialization.OptIn)]
public class ActionTargetIdsCacheItemInfo : ISerializable
{
public ActionTargetIdsCacheItemInfo()
{
lastUpdatedTimeStamp = DateTime.UtcNow;
actionTargetIds = new List<string>();
}
public ActionTargetIdsCacheItemInfo(SerializationInfo info, StreamingContext context)
{
lastUpdatedTimeStamp = info.GetDateTime("lastUpdated");
actionTargetIds = (List<string>)info.GetValue("actionTargetIds", typeof(List<string>));
}
[JsonProperty]
public DateTimeOffset lastUpdatedTimeStamp { get; set; } = DateTimeOffset.UtcNow;
[JsonProperty]
public List<string> actionTargetIds { get; set; } = new List<string>();
public void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.AddValue("lastUpdated", lastUpdatedTimeStamp);
info.AddValue("actionTargetIds", actionTargetIds);
}
}
public interface IActionTargetIdCache
{
void CacheCleanup(DateTime currentUtcTime);
void DeleteActionTargetIds(string officeHolderId);
void DeleteState();
void SetActionTargetIds(ActionTargetIdsCacheEntry item);
// Task Reset();
Task<ActionTargetIdsCacheItemInfo> GetActionTargetIdsAsync(string officeHolderId);
// void Delete();
}
Here is the exception I get during the first attempt to access the state from an orchestration using the GetActionTargetIdsAsync method:
Exception has occurred: CLR/Microsoft.Azure.WebJobs.Extensions.DurableTask.EntitySchedulerException
Exception thrown: 'Microsoft.Azure.WebJobs.Extensions.DurableTask.EntitySchedulerException' in System.Private.CoreLib.dll: 'Failed to populate entity state from JSON: Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'PolTrack.CdbGetFunctionApp.ActionTargetIdsCacheItemInfo' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List<T> that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.
Path 'cache.officeHolderId1', line 1, position 29.'
Inner exceptions found, see $exception in variables window for more details.
Innermost exception Newtonsoft.Json.JsonSerializationException : Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'PolTrack.CdbGetFunctionApp.ActionTargetIdsCacheItemInfo' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List<T> that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.
Path 'cache.officeHolderId1', line 1, position 29.
Could someone with the sufficient SO privileges please add the tag azure-durable-entities.

Answer 1

I did manage to get around this by following #silent suggestion. I re-designed the entity class to only use CLR types. In my case, that meant replacing Dictionary<string, ActionTargetIdsCacheItemInfo> with two dictionaries Dictionary<string, List<string>> and Dictionary<string, DateTimeOffset>.