Clean up deactivated Slack users from shared channels

cleanup-deactivated-slack-users.rb

require 'json'

BASE_URL = 'https://slack.com/api'
TOKEN = ENV['SLACK_TOKEN']
BACKOFF = 0.2

channels_url = "#{BASE_URL}/conversations.list?token=#{TOKEN}"
channels = JSON.parse(`curl -s '#{channels_url}'`)['channels']
sleep BACKOFF

users_url = "#{BASE_URL}/users.list?token=#{TOKEN}"
users = JSON.parse(`curl -s '#{users_url}'`)['members']
deleted_users = Hash[
  users.select { |u| u['deleted'] }.map { |u| [u['id'], u['name']] }
]

shared_channels = channels.select { |c| c['is_shared'] }
shared_channels.each do |channel|
  puts "Reviewing memberships in ##{channel['name']}..."
  members_url = "#{BASE_URL}/conversations.members" \
                "?token=#{TOKEN}&channel=#{channel['id']}"
  member_ids = JSON.parse(`curl -s '#{members_url}'`)['members']
  sleep BACKOFF

  member_ids.each do |member_id|
    next unless deleted_users.keys.include?(member_id)
    puts "  Kicking @#{deleted_users[member_id]} from ##{channel['name']}"
    kick_url = "#{BASE_URL}/conversations.kick?token=#{TOKEN}" \
               "&channel=#{channel['id']}&user=#{member_id}"
    status = JSON.parse(`curl -s '#{kick_url}'`)
    fail "Error: #{status}" unless status['ok']
    sleep BACKOFF
  end
end