Slack Next-gen Platform – “reaction_added” Event Trigger

$ slack create
? Select a template to build from:

  Hello World
  A simple workflow that sends a greeting

  Scaffolded project
  A solid foundational project that uses a Slack datastore

> Blank project
  A, well.. blank project

  To see all available samples, visit github.com/slack-samples.

$ cd affectionate-panther-654
$ slack run
? Choose a workspace  seratch  T03E94MJU
   App is not installed to this workspace

Updating dev app install for workspace "Acme Corp"

  Outgoing domains
   No allowed outgoing domains are configured
   If your function makes network requests, you will need to allow the outgoing domains
   Learn more about upcoming changes to outgoing domains: https://api.slack.com/future/changelog
  seratch of Acme Corp
Connected, awaiting events

// ----------------
// Workflow Definition
// ----------------
import { DefineWorkflow, Schema } from "deno-slack-sdk/mod.ts";
export const workflow = DefineWorkflow({
  callback_id: "example-workflow",
  title: "Example Workflow",
  input_parameters: {
    properties: {
      // All the possible inputs from the "reaction_added" event trigger
      channel_id: { type: Schema.slack.types.channel_id },
      user_id: { type: Schema.slack.types.user_id },
      message_ts: { type: Schema.types.string },
      reaction: { type: Schema.types.string },
    },
    required: ["channel_id", "user_id", "message_ts", "reaction"],
  },
});

// TODO: Add function steps here

// ----------------
// Trigger Definition
// ----------------
import { Trigger } from "deno-slack-api/types.ts";
const trigger: Trigger<typeof workflow.definition> = {
  type: "event", // Event Trigger
  name: "Trigger the example workflow",
  workflow: `#/workflows/${workflow.definition.callback_id}`,
  event: {
    // "reaction_added" event trigger
    event_type: "slack#/events/reaction_added",
    channel_ids: ["C04FB5UF1C2"], // TODO: Update this list
    // The condition to filter events
    filter: {
      version: 1,
      // Start the workflow only when the reaction is :eyes:
      root: { statement: "{{data.reaction}} == eyes" },
    },
  },
  inputs: {
    channel_id: { value: "{{data.channel_id}}" },
    user_id: { value: "{{data.user_id}}" },
    message_ts: { value: "{{data.message_ts}}" },
    reaction: { value: "{{data.reaction}}" },
  },
};
export default trigger;

import { Manifest } from "deno-slack-sdk/mod.ts";
import { workflow as DemoWorkflow } from "./workflow_and_trigger.ts";

export default Manifest({
  name: "distracted-bison-253",
  description: "Demo workflow",
  icon: "assets/default_new_app_icon.png",
  workflows: [DemoWorkflow],
  outgoingDomains: [],
  botScopes: [
    "commands",
    "chat:write",
    "reactions:read", // required for the "reaction_added" event trigger
    "channels:history", // will use in custom functions later
    "channels:join", // will use in custom functions later
  ],
});

$ slack triggers create --trigger-def ./workflow_and_trigger.ts
? Choose an app  seratch (dev)  T03E*****
   distracted-bison-253 (dev) A04FNE*****

⚡ Trigger created
   Trigger ID:   Ft04EJ8*****
   Trigger Type: event
   Trigger Name: Trigger the example workflow   

$ slack run
? Choose a workspace  seratch  T03E94MJU
   distracted-bison-253 A04FACHPQ5R

Updating dev app install for workspace "Acme Corp"

⚠️  Outgoing domains
   No allowed outgoing domains are configured
   If your function makes network requests, you will need to allow the outgoing domains
   Learn more about upcoming changes to outgoing domains: https://api.slack.com/future/changelog
✨  seratch of Acme Corp
Connected, awaiting events

2022-12-15 10:03:50 [info] [Fn04FCVD67J8] (Trace=Tr04G077TW80) Function execution started for workflow function 'Example Workflow'
2022-12-15 10:03:50 [info] [Wf04FP576X3K] (Trace=Tr04FP5F70HX) Execution started for workflow 'Example Workflow'
2022-12-15 10:03:51 [info] [Fn04FCVD67J8] (Trace=Tr04G077TW80) Function execution completed for function 'Example Workflow'
2022-12-15 10:03:51 [info] [Wf04FP576X3K] (Trace=Tr04FP5F70HX) Execution completed for workflow 'Example Workflow'

import { DefineFunction, Schema, SlackFunction } from "deno-slack-sdk/mod.ts";

export const def = DefineFunction({
  callback_id: "reply_to_reaction",
  title: "Reply to a reaction in a channel",
  source_file: "function.ts",
  input_parameters: {
    properties: {
      channel_id: { type: Schema.slack.types.channel_id },
      user_id: { type: Schema.slack.types.user_id },
      reaction: { type: Schema.types.string },
      message_ts: { type: Schema.types.string },
    },
    required: ["channel_id", "user_id", "reaction", "message_ts"],
  },
  output_parameters: {
    properties: { ts: { type: Schema.types.string } },
    required: ["ts"],
  },
});

export default SlackFunction(def, async ({ inputs, client }) => {
  // https://api.slack.com/methods/conversations.join
  // requires "channels:join" scope in manifest.ts
  const joinResponse = await client.conversations.join({
    channel: inputs.channel_id,
  });
  if (joinResponse.error) {
    const error = `Failed to join the channel due to ${joinResponse.error}`;
    return { error };
  }
  // https://api.slack.com/methods/conversations.history
  // requires "channels:history" scope in manifest.ts
  const historyResponse = await client.conversations.history({
    channel: inputs.channel_id,
    latest: inputs.message_ts,
    inclusive: true,
    limit: 1,
  });
  if (historyResponse.error) {
    const error =
      `Failed to fetch the channel content due to ${joinResponse.error}`;
    return { error };
  }
  const messageText = (historyResponse.messages[0].text ||
    "(Failed to fetch the message text)").replaceAll("\n", "\n>");
  const replyText =
    `Hey <@${inputs.user_id}>, thanks for adding :${inputs.reaction}: to the following message:\n>${messageText}`;
  // https://api.slack.com/methods/chat.postMessage
  // requires "chat:write" scope in manifest.ts
  const replyResponse = await client.chat.postMessage({
    channel: inputs.channel_id,
    text: replyText,
  });
  if (replyResponse.error) {
    const error = `Failed to post a message due to ${replyResponse.error}`;
    return { error };
  }
  return { outputs: { ts: replyResponse.ts } };
});

import { def as reply } from "./function.ts";
workflow.addStep(reply, {
  channel_id: workflow.inputs.channel_id,
  user_id: workflow.inputs.user_id,
  reaction: workflow.inputs.reaction,
  message_ts: workflow.inputs.message_ts,
});