How to send direct messages to a user as app in app channel - slack

Question

How is it possible to send message in slack directly to the user, by user.id as application.
this application has scope: bot,channels:write,emoji:read,users:read,users:read.email
I find how to send message only as DM or by webhooks, but there is no scope for that. Any one has idea?

Answer 1

If I understand your question correctly, you want to send direct messages to users in the app channel instead of the standard slackbot channel.
In order to do that you need to
Your app needs the bot scope and a bot user
Open a direct message channel from your app with the user with conversations.open. You get back a direct message ID.
Send a message with chat.postMessage to the the direct message channel ID
Make sure to use your bot access token (not the user access token) from your Slack app.
The bot scope gives you all permissions needed to open and send DMs to users from your bot channel. No other scopes are required.
You can also use the new conversations methods, which work for all kind of channel types to do the same.
See also this question on the same topic.

Answer 2

There is an alternative way to solve this, which can be more suitable if your app uses a bot to operate with Slack API.
You need to call chat.postMessage API method and specify channel argument equal to the user ID (e.g. U0G9QF9C6) you want to message and as_user argument is true.
Important detail - ensure you are using bot access token (learn here how to obtain it).
Example:
curl -X POST "https://slack.com/api/chat.postMessage" -H "accept: application/json" -d token=BOT_ACCESS_TOKEN -d channel=U0G9QF3C6 -d text=Hello -d as_user=true
In this way, your message will be always sent on behalf (name and icon) of your bot and will be display like a direct message in the app channel (YourAppChannel in the Slack sidebar).
Compared to the approach of #ErikKalkoken you have no need to create a channel in advance and as a result, keep track of its ID (it may be good or bad depending on your needs).

Answer 3

For those who is still searching for detailed answer:
First of all you need to make call to this endpoint.
You need to make call with bot token and provide into users param value of user you want to send message.
Also you need set prevent_creation and return_im to true.
Example:
Authorization: Bearer {your_bot_token}
{
"users": "U12345679",
"prevent_creation": true,
"return_im": true
}
After that you will have your channel id to which you want to send message.
Example response:
{
"ok": true,
"no_op": true,
"already_open": true,
"channel": {
"id": "D123456789", <-- this is your id
...
"unread_count": 0,
"unread_count_display": 0,
"is_open": true,
"priority": 0
}
}
and then with same bot token and user id send message with help of this one
Blockquote I keep getting {"ok":false,"error":"not_in_channel"} do i need to manually add the bot to a channel?? –
Abhijeet Bajracharya
Feb 4 '20 at 8:04
you need to get scope that allow to send messages like this

Answer 4

There is no need to use the conversation.info, you can post message (DM), by using the users.list endpoint and fetch the user id, which then you can use in chat.postMessage