How can I start a conversation with user data like user name, user domain ID - botframework

Question

I need to develop enhancements to an existing app which will interact with a bot developed using MS bot framework. For this, I am thinking of utilising the Direct Channel. However, I dont understand, how I can pass on user specific information from the app to the bot.
In documentation available at https://learn.microsoft.com/en-us/bot-framework/rest-api/bot-framework-rest-direct-line-3-0-send-activity,
It is mentioned that the payload of the REST request would be
{
"type": "message",
"from": {
"id": "user1"
},
"text": "hello"
}
Where should I pass on the user specific or sessions information like user first name, last name, email id or Login id or initiating app or location from where the user is initiating the chat or anything else here ?
Any guidance will help.

Answer 1

How can I start a conversation with user data like user name, user domain ID
As NicolasR pointed, it does not enable us to attach/specify user information when starting a conversation on Direct Line Channel.
how I can pass on user specific information from the app to the bot
If you’d like to send activity and pass user information (firstname, lastname etc) to your bot by using the Direct Line API, as you see in that documentation, to send an activity to the bot, the client must create an Activity object to define the activity. You can refer to the following example request to contains the user information in from field of your request JSON payload.
In my bot app code (c#), I can extract user information from Activity object using the following code snippet.
if (activity.From.Properties["firstname"] != null)
{
var fname = activity.From.Properties["firstname"].ToString();
}