Messaging

Messaging

This sub-app guides you on how to post a channel message via the built-in SendMessage, SendEphemeralMessage, and SendDm functions. If you haven't set up the Slack CLI and the project on your local machine yet, visit the top-level guide document first.

Supported Workflows

• Channel Message Workflow: Send an "in_channel" message, which is visible to everyone in a public channel
• Ephemeral Message Workflow: Send an "ephemeral" message, which is visible only to a specific person in a public channel
• Direct Message Workflow: Open a DM with a person and send a message in the private conversation

Channel Message Workflow

When you run ./Messaging/workflows/channel_message.ts workflow, it sends a "Hello World!" message in a public channel. All you need to do are:

1. Create a trigger to start the workflow
2. Run your application using slack run
3. Invoke the workflow via the created trigger

Create Triggers

Triggers are what cause workflows to run. These triggers can be invoked by a user or automatically as a response to an event within Slack.

By running this workflow, you will learn how to create and use two types of triggers.

• Link trigger
• Webhook trigger

Either way, the workflow posts a message in a public channel. Let's start with a link trigger.

Create a Link Trigger

A link trigger is a type of trigger that generates a Shortcut URL, which, when posted in a channel or added as a bookmark, becomes a link. When clicked, the link trigger will run the associated workflow.

Link triggers are unique to each installed version of your app. This means that Shortcut URLs will be different across each workspace, as well as between locally run and deployed apps. When creating a trigger, you must select the workspace that you'd like to create the trigger in. Each workspace has a development version (denoted by (local)), as well as a deployed version.

To create a link trigger for the workflow in this template, run the following command:

$ slack trigger create --trigger-def ./Messaging/triggers/channel_message_link.ts

After selecting a Workspace, the output provided will include the link trigger Shortcut URL. Copy and paste this URL into a channel as a message, or add it as a bookmark in a channel of the workspace you selected.

Running slack trigger create command automatically installs your app with the latest manifest metadata. Thus, your workflow is now ready to invoke. Once you run the workflow, you will see "Hello World!" message in the same channel 🎉

Create a Webhook Trigger

A webhook trigger is a type of a trigger that runs its associated workflow when a specific URL receives a POST request.

To create a webhook trigger for the workflow in this template, run the following command:

$ slack trigger create --trigger-def ./Messaging/triggers/channel_message_webhook.ts

After selecting a Workspace, the output provided will include the webhook URL starting with https://hooks.slack.com/triggers/. You can send "Hello World!" message to a public channel by sending an HTTP POST request with a channel ID to the webhook URL. The easiest way to know a channel ID is to click a channel name in the Slack client UI, scroll down to the bottom in the popup modal, and then copy the string starting with a "C" letter.

$ curl -XPOST https://hooks.slack.com/triggers/your-url..... -d '{"channel_id": "C1234567890"}'

When you pass a valid public channel in the request body, you will see the same "Hello World" message in the specified channel 🎉

Ephemeral Message Workflow

Similarly, you can send an ephemeral message, which is visible to a specific user, from a workflow. Create a link trigger:

$ slack trigger create --trigger-def ./Messaging/triggers/ephemeral_message_link.ts

You can invoke the ./Messaging/workflows/ephemeral_message.ts workflow from the link trigger button. Then, you will receive an "Only visible to you" message from the app.

Direct Message Workflow

Lastly, try one more built-in function, which sends a direct message from your app.

$ slack trigger create --trigger-def ./Messaging/triggers/direct_message_link.ts

When you invoke the ./Messaging/workflows/direct_message.ts workflow from the link trigger, you will receive a DM from the app 🎉

Deploying Your App

Once you're done with development, you can deploy the production version of your app to Slack hosting using slack deploy:

$ slack deploy

After deploying, create a trigger for the production version of your app (not appended with (local)). Once the trigger is invoked, the workflow should run just as it did when developing locally.

Viewing Activity Logs

Activity logs for the production instance of your application can be viewed with the slack activity command:

$ slack activity

Project Structure

manifest.ts

The app manifest contains the app's configuration. This file defines attributes like app name and description.

slack.json

Used by the CLI to interact with the project's SDK dependencies. It contains script hooks that are executed by the CLI and implemented by the SDK.

Messaging/workflows

A workflow is a set of steps that are executed in order. Each step in a workflow is a function.

Workflows can be configured to run without user input, or they can collect inputs by beginning with a form before continuing to the next step.

Messaging/triggers

Triggers determine when workflows are executed. A trigger file describes a scenario in which a workflow should be run, such as a user pressing a button or when a specific event occurs.

What's Next?

To learn more about other samples, visit the top-level guide to find more!