Webhook Triggers

Invoke a Workflow when a specific URL receives a POST request

Webhook Triggers are an automatic type of Trigger that listens for a certain type of data, much like Event Triggers.

While Event Triggers are used for activating a Trigger based on internal activity, webhooks are instead used when activating a Trigger based on external activity. In other words, Webhook Triggers are useful when tying Slack functionality together with non-Slack services.

There are three steps to using a Webhook Trigger:

1. Define the Trigger
2. Create the Trigger, either via the CLI or at runtime
3. Invoke the Trigger with a POST Request

1. Define the Trigger

A Trigger contains a Typescript payload with the following parameters:

Parameters

Example TypeScript payload

The following is a TypeScript payload for creating a Webhook Trigger:

  type: "webhook",
  name: "sends 'how cool is that' to my fav channel",
  description: "runs the example workflow",
  workflow: "#/workflows/myWorkflow",
  inputs: {
    stringToReverse: {
      value: "how cool is that",
    },
    channel: {
      value: "{{data.channel}}",
    },
  }

2. Create the Webhook Trigger

There are two ways to create a Webhook Trigger. You can:

• create a Webhook Trigger with the CLI
• create a Webhook Trigger at runtime

Create a Webhook Trigger with the CLI

To create a Webhook Trigger with the CLI, you'll need to create a trigger file. The trigger file contains the payload you used to define your Trigger.

TypeScript trigger files take the following form:

import { Trigger} from “deno-slack-api/types.ts”;

const trigger : Trigger<typeof ExampleWorkflow.definition> = {
  // your TypeScript payload 
}

export default trigger;

Once you have created a trigger file, use the following command to create the Webhook Trigger:

slack trigger create --trigger-def "path/to/trigger.ts"

Create a Webhook Trigger at runtime

Create a Webhook Trigger at runtime using the client.workflows.triggers.create method within the relevant Function file.

const triggerResponse = await client.workflows.triggers.create<typeof ExampleWorkflow.definition>({
  // your TypeScript payload
);

3. Invoke the Trigger

Send a POST request to invoke the Trigger. Within that POST request you can send values for specific inputs.

Example POST request

curl \ 
-X POST "https://hooks.slack.com/triggers/T123ABC456/.../..." \
--header "Content-Type: application/json" \
--data "{"channel":"C123ABC456"}" 

If successful, you'll get the following response:

{
  "ok":true
}