Send slack message via api using `xoxp` User token 

• Create an app here: https://api.slack.com/apps
  • You can see newly created Slack app here: https://api.slack.com/apps/
  • On App screen, click OAuth & Permissions in the sidebar.
    • Under User Token Scopes section, click Add an OAuth Scope
    • Under OAuth Tokens , click Install to Productiwitty. This will generate User OAuth Token starting with xoxp.

Now install slack_sdk inside virtualenv using:

pip install slack_sdk

Then you can send messages via Slack API using following Python 3 code:

#!/usr/bin/env python3
import datetime
from slack_sdk import WebClient

# ID of channel you want to post message to
#
channel_id = "CXXXXXXX"

user_token = "xoxp-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"

client = WebClient(user_token)

def send_slack_message(channel_id, msg):
    try:
        result = client.chat_postMessage(
            channel=channel_id,
            text=msg
        )
        print(result)

    except SlackApiError as e:
        print(f"Error: {e}")

send_slack_message(channel_id, "hello")

You can also schedule a message using this code:

def schedule_msg(channel_id, at_hour, at_minute, msg, day):
    scheduled_time = datetime.time(hour=at_hour, minute=at_minute)
    schedule_timestamp = datetime.datetime.combine(day, scheduled_time).strftime('%s')
    try:
        result = client.chat_scheduleMessage(
            channel=channel_id,
            text=msg,
            post_at=schedule_timestamp
        )
        print(result)
    except Exception as e:
        print(f"EXCEPTION!!! {e}")

today = datetime.date.today()

# Schedule a message to be sent at 23:35 (11:35pm) today:
schedule_msg(channel_id, 23, 35, "bye", today)