InvokeResponse handlers should not use `object` for accessing the incoming data

[rido-min]

Agents-for-net/src/libraries/Extensions/Microsoft.Agents.Extensions.Teams/App/MessageExtensions/MessageExtensionsHandlers.cs

Line 24 in 0c55c36

public delegate Task<MessagingExtensionActionResponse> SubmitActionHandlerAsync(ITurnContext turnContext, ITurnState turnState, object data, CancellationToken cancellationToken);

[tracyboehrer]

The type being passed in is 'object'. The recommended pattern for all 'object' types on payloads is ProtocolJsonSerialzier.ToObject if there is a known type. Otherwise it's JsonElement manipulation. We have avoided using serializer natives in the models.

[tracyboehrer]

What should be investigated is something like what AdaptiveCard.SearchHandler does... takes a type which is converted before calling. A guess though... in places where object is used this is likely/possibly user defined structures and they can use ToObject to convert since only they know what the content is. In DotNet SDK, object can be JsonElement, POCO, primitive, or a JSON string (assuming a converter is applied).

[rido-min]

With generics, we can allow the customer to use their custom types as T, so the handler could be something like:

 public delegate Task<MessagingExtensionActionResponse<T>> SubmitActionHandlerAsync(ITurnContext turnContext, ITurnState turnState, T data, CancellationToken cancellationToken); 

[tracyboehrer]

With generics, we can allow the customer to use their custom types as T, so the handler could be something like:

public delegate Task<MessagingExtensionActionResponse> SubmitActionHandlerAsync(ITurnContext turnContext, ITurnState turnState, T data, CancellationToken cancellationToken);

But we are the ones that call the handler, and what we have is object that would have to be casted or converted (ToObject). This object scenario is relatively common, not just for MessageExtensions. It's all over. Could be MessagingExtensionAction.Data as in your reference, but for others I've seen Activity.Value. Though I didn't investigate all.

Not something I'd execute on this close to GA or Build. But I understand the motivation.