How to emit an event in express js and handle it in discord.js - express

Question

I have a simple express.js backend that handles a get request from discord which runs a heavy process in the background using bull and throng.
I got it all working, Discord sends the get request. backend reserves the request and adds it to the job queue, once it's done I receive the returned value in the Queue.on() listener.
My problem is how can I send this result I get in the queue.on() listener back to discord as a message. how can I make discord listen to this event and post the result?
Note: discord and express are 2 separate apps. can't integrate them into one project.
Index.js file:
const express = require('express')
const scrapTikTok = require('./tiktokScraping')
const Queue = require('bull')
const app = express()
// Initialize BULL
const REDIS_URL = process.env.REDIS_URL || 'redis://127.0.0.1:6379'
const workQueue = new Queue('work', REDIS_URL, {
defaultJobOptions: {
removeOnComplete: true,
removeOnFail: true
}
})
app.get('/scrap', async (req, res) => {
res.send('Working on it...')
await scrapTikTok()
})
app.get('/url', async (req, res) => {
const url = 'https://www.tiktok.com/#tristanvincentt'
let job = await workQueue.add({url: url})
res.json({id: job.id})
})
workQueue.on('global:completed', (jobId, result) => {
console.log(`Job completed with result ${result}`)
// SEND RESULT BACK TO DISCORD
})
app.listen(process.env.PORT || 3000, () => {
console.log('App is running...')
})
Worker file:
const throng = require('throng')
const Queue = require("bull")
const REDIS_URL = process.env.REDIS_URL || "redis://127.0.0.1:6379"
const workers = process.env.WEB_CONCURRENCY || 1
const maxJobsPerWorker = 50
const sleep = ms => new Promise(r => setTimeout(r, ms));
function start() {
const workQueue = new Queue('work', REDIS_URL)
workQueue.process(maxJobsPerWorker, async job => {
console.log(job.data.url)
await sleep(10000)
return {value: job.id}
})
}
throng({workers, start})

Answer 1

you can create another express server in your discord app. and add a post endpoint:
const express = require('express')
const app = express()
app.post('/secreturl', async (req, res) => {
res.send('Discordjs Received the data!')
let jobId = req.body.jobId
let result = req.body.result
//now you have the results here!
})
then when the queue is done (based on the code you provided):
workQueue.on('global:completed', (jobId, result) => {
console.log(`Job completed with result ${result}`)
// SEND RESULT BACK TO DISCORD:
axios.post('(your-discordjs-server-ip)/secreturl', {
jobId: jobId,
result: result
})
})
just make sure you add the axios package to the queue app
npm install axios
and require it in the index.js file
const axios = require("axios")
tick this as the answer if it solved your problem!