How to get the user id from Slack to bot service - node.js

Question

I am creating a simple bot using Azure LUIS and this is my first one. I made some decent progress after doing some research and also now integrated with Slack as channel to test it.
The bot functionality is working fine, but I am looking to identify the user. So that I can personalize the bot conversation and also to pull the user specific information from his profile table.
Is there anyway, that I can get a UID or any reference ID of the slack user and so I can store that in my user table along with user profile?
So next time, when the user greets the bot, the bot can say "Hello, John." instead of justing say "Hello."
Thanks!

Answer 1

Yes. You can use the channelData object to get the ApiToken, and user values. For example, in C#, you could use turnContext.Activity.ChannelData to get those values in JSON:
{{
"SlackMessage": {
"token": "............",
"team_id": "<TEAM ID>",
"event": {
"type": "message",
"text": "thanks",
"user": "<USER WHO MESSAGED>",
"channel": "............",
"channel_type": "channel"
},
"type": "event_callback",
"event_id": ""............",
"event_time": 1553119134,
"authed_users": [
"............",
"<USER WHO MESSAGED>"
]
},
"ApiToken": "<ACTUAL TOKEN HERE>"
}}
Then, using those two pieces of information, you can then retrieve info from Slack.
https://slack.com/api/users.info?token=<ACTUAL TOKEN HERE>&user=<USER WHO MESSAGED>&pretty=1
And get a response that has the info you need:
{
"ok": true,
"user": {
"id": "<USER WHO MESSAGED>",
"team_id": "<TEAM ID>",
"real_name": "Dana V",
Ideally, you would would probably want to have bot user state setup and check that first, then if not there, then make the API call to Slack, then store in state. Therefore further requests don't need to go to Slack, but will just pull from the state store.
Basically, you could/should do this in the onTurn event. First, create your user state storage such as here.
Then you could check for that value and write to it if not populated. This example on simple prompts, might be helpful. You won't need to prompt for your user's name, as this example does, but does read/write username from state. You could still use dialogs, but you won't need them for the name prompting as you are doing that dynamically.
You can see here where username is being set and here where it is being retrieved. In this case, it is in the dialogs, but again; you would/could just do in the turn context (using logic to get and if not there, set).

Answer 2

I found the solution by priting the whole session object, which is having all the required informaiton. This could be same as mentioned by Dana above, but after debugging, this follwing made simple without making any changes.
var slackID = session.message.address.user.id
With above, I am able to identify the user.
Thanks.