What is this?

This bot can echo messages between specified channels.
This bot runs as a web app within a Google app script.
You can make this bot work by registering it as an endpoint for Slack API event subscriptions.

REQUIREMENTS

• npm
• clasp
  npm install -g @google/clasp
• make

USAGE

To use it, you need to set up Google apps scripts and Slack API.

Install Google apps scripts

1. Enable Google Apps Script API
   https://script.google.com/home/usersettings
2. make push
3. make deploy
4. Grant the necessary privileges
   make open
   Publish > Deploy as web app.. > Update
   Grant access

Register with the Slack API

• Create New App
  https://api.slack.com/apps
  Please make a note of App Credentials displayed after registration.

Setting Script properties

In order to run the application and change its behavior, you need to set the following Google Apps scripts property.

Property name	Required	Setting Value	Description
VERIFICATION_TOKEN	○	Basic Information > App Credentials > Verification Token	A token that easily authenticates the source of a hooked request
CLIENT_ID	○	Basic Information > App Credentials > Client ID	Use with OAuth
CLIENT_SECRET	○	Basic Information > App Credentials > Client Secret	Use with OAuth
SLACK_WORKSPACE_NAME	optional	your workspace's name. e.g.) https://example.slack.com
ACCESS_TOKEN	optional	Set automatically by oauth authentication	Access token issued after oauth authentication.
CHANNEL_NAME	optional	Set automatically by oauth authentication	Channel name specified during oauth authentication.
BOT_USER_ID	optional	Set automatically by oauth authentication	ID of bot user registered with slack api.

1. Open Project
   $ make open
2. Add Scirpt properties
   File > Project properties > Scirpt properties > Add row
   Setting Property & Value

OAuth Authentication

Settings OAuth & Permissions

• Redirect URLs
  Add New Redirect URL > Add Redirect URL > Save URLs
  ex) https://script.google.com/macros/s/miserarenaiyo/usercallback
  You can check the Redirect URL in the following way. The RedirectUri of the displayed page.
  $ make application
• Bot Token Scopes
  Click Add an OAuth Scope to select the following permissions
  • chat:write
  • channels:read
  • channels:history
  • users.profile:read
  • team:read
  • incoming-webhook
• Install App to Workspace
  You must specify a destination channel that bot can post to as an app.

Install App to Workspace

1. Open web application
   $ make application
   The browser will be launched with the following URL:
   ex) https://script.google.com/macros/s/miserarenaiyo/exec
2. Click Authorize.
   You must specify a destination channel that bot can post to as an app.
3. Click Allow
   The following message is displayed when OAuth authentication is successful

Success!
Setting EventSubscriptions

When prompted, click the Setting EventSubscriptions to set up an Event Subscriptions.

Setting Event Subscriptions

Turn on.
Setting Request URL.
ex) https://script.google.com/macros/s/miserarenaiyo/exec
Add Workspace Event.
Select message.channels.