Building Slack Bots

Slackbots are a great way to automate your app based on events happening in your workspace. Additionally, they are another way to interact with users in a more personal way. Create your bot easier with Transposit.

Prerequisites

• A Slack App
• An application in Transposit

Create a webhook in Transposit

• Follow the instructions at the webhooks docs page to create a webhook operation.
• If planning on using event subscriptions, add code into the http_event function to pass the url_verification event. This is due to Dynamic Challenges.

if (http_event.parsed_body.challenge) {
  return {
    status_code: 200,
    headers: { "Content-Type": "text/plain" },
    body: http_event.parsed_body.challenge
  };
}

• Commit your code.
• Navigate to Deploy > Endpoints and change the operation webhook from Not deployed to Deployed if needed.
• Check the box for Deploy as webhook and copy the deployed URL it produces.

Setting up a Slack event to POST to your webhook

• In your Slack App configure page, select Event Subscriptions, and paste in the URL you copied from Transposit. If you copied the Dynamic Challenge code correctly, it should automatically verify that the function is valid.
• Install the Slack app with proper permissions into your workspace.

Sample webhooks

The challenge response is a goode example of a simple webhook function. You can also create a webhook function in SQL if you prefer.

SELECT {
    status_code: 200,
    headers: { "Content-Type": "application/json" },
    body: {
    	text: "Hello World, from SQL!"
    }
}

Your webhook function will be called whenever the events you decide to follow occur in your workspace. Adding helper functions and other API calls before the return statement can add to the ability to customize output.

Selecting events to follow

Bot users aren't just another face to post a message as, they can be used to scan for many events in the organization as a way to trigger your webhook function. Slack Events API contains a large number of events that can either happen in your workspace, or your bot is a part of to POST. Additionally, can you use App Unfurl Domains to have the event trigger upon a user posting a link from a select domain. Some common events to use are:

• message.channels
• message.im
• app_mention
• reaction_added
• team_join

Acting as your bot user

While Transposit makes it easy to authenticate with your Slack account, in order to act as your bot, we need to manually input the credentials of the bot. Otherwise the application will continue to execute as you.

• Find your Client ID and Secret in your Slack app under Basic Information > App Credentials.
• In your Transposit app, go to Code > Data connections > slack > Authentication and change the values to your Slack app's Client ID and Secret.
• On the same page, edit the Configuration with AccessTokenPath bot.bot_access_token, and Scope equal to the scopes you have selected in OAuth & Permissions in Slack.
• In OAuth & Permissions in Slack, add https://accounts.transposit.com/oauth/v2/handle-redirect as a redirect URL.
• Reinstall your app in Slack.
• Reauthenticate Slack in Transposit. You can do this by going to Code > Auth & settings and disconnecting then connecting the Slack key. (Note you'll need to do this for all Slack keys you've set up.)

If done correctly, it should authenticate the Transposit application as the bot user, instead of you. When you post a message (if you have given your bot chat:write:bot permissions) you should see the message posted as the bot.

Viewing POSTed data

You can view the data sent to your webhook from Slack in the Monitor tab, or by returning the data in the response.

({ http_event }) => {
  return {
    status_code: 200,
    headers: { "Content-Type": "application/json" },
    body: { text: JSON.stringify(http_event, null, 2) }
  };
};

This gives us the full HTTP request; most of what we are interested in is in the body. Transposit parses the body according to the type specified in the headers. You'll see something like this:

 "parsed_body": {
    "token": "<token>",
    "team_id": "XXXXXXXXX",
    "api_app_id": "XXXXXXXXX",
    "event": {
      "type": "team_join",
      "user": {
        "id": "XXXXXXXXX",
        "team_id": "XXXXXXXXX",
        "name": "user",
        "deleted": false,
        "color": "ea2977",
        "real_name": "name",
        "tz": "America/Los_Angeles",
        "tz_label": "Pacific Daylight Time",
        "tz_offset": -25200,
        ...
        "is_admin": false,
        "is_owner": false,
        "is_primary_owner": false,
        "is_restricted": false,
        "is_ultra_restricted": false,
        "is_bot": false,
        "is_app_user": false,
        "updated": 1565992213,
        "presence": "away"
      },
      "cache_ts": 1565992213,
      "event_ts": "1565992213.000800"
    },
    "type": "event_callback",
    "event_id": "XXXXXXXXX",
    "event_time": 1565992213,
    "authed_users": [
      "XXXXXXXXX"
    ]
 },

We already set this to pass the challenge back to Slack above, where we used http_event.parsed_body.challenge. This can be done with any of the labels in the webhook.

Return to Slack landing page