activity.entites does not pass custom object - botframework

Question

In botframework v3 I used to be able to pass any object in the entities of a message. In v4, I can pass only object with the "type" string member. At least as shown in the Bot emulator.
Why is this? Is there another way to pass custom objects? I have customers that are using the v3 way to pass objects as message metadata

Answer 1

While much has changed in V4, there is no significant difference between V3 and V4 when it comes to activities. You can still use entities to pass metadata in activities. Other ways to include metadata in activities are:
ChannelData
Properties
Value
Consider the following code:
private async Task TestEntitiesAsync(ITurnContext tc,
CancellationToken cancellationToken)
{
var reply = tc.Activity.CreateReply("reply");
var entity = new Entity("test")
{
Properties = JObject.FromObject(new { Foo = "Entity", Bar = 1 }),
};
reply.Entities = new[] { entity };
reply.ChannelData = new { Foo = "ChannelData", Bar = 2 };
reply.Properties = JObject.FromObject(new { Foo = "Properties", Bar = 3 });
reply.Value = new { Foo = "Value", Bar = 4 };
await tc.SendActivityAsync(reply);
}
The JSON of the activity it generates looks like this:
{
"Bar": 3,
"Foo": "Properties",
"attachments": [],
"channelData": {
"Bar": 2,
"Foo": "ChannelData"
},
"channelId": "emulator",
"conversation": {
"id": "xxxx|livechat"
},
"entities": [
{
"Bar": 1,
"Foo": "Entity",
"type": "test"
}
],
"from": {
"id": "3",
"name": "Bot",
"role": "bot"
},
"id": "xxxx",
"localTimestamp": "2018-12-26T15:33:36-08:00",
"locale": "en-us",
"recipient": {
"id": "xxxx",
"role": "user"
},
"replyToId": "xxxx",
"serviceUrl": "http://localhost:1234",
"text": "reply",
"timestamp": "2018-12-26T23:33:36.022Z",
"type": "message",
"value": {
"Bar": 4,
"Foo": "Value"
}
}
I recommend using Activity.Properties because ChannelData, Entities, and Value all have predefined uses, though they all should still serve your purposes in most cases. Remember that everything you write in C# (or whatever language you're using) is just going to be converted into JSON and sent through an HTTP message. The SDK is just providing an easy way of implementing the schema.