Make private Trello board attachments publicly-available. https://glitch.com/edit/#!/private-trello-attachment-proxy

private-trello-attachment-proxy.js

require('dotenv').config()
const express = require('express')
const fetch = require('node-fetch')

const app = express()

app.use('/', async (req, res) => {

	// Attachment URL
	const attachmentURL = "https://trello.com/1/cards/5e65954f0f343116e999658f/attachments/5e67a146876719748d64057b/previews/5e67a147876719748d6405ae/download"

	// Add auth headers and request image
	const image = await fetch(attachmentURL, {
		method: "GET",
		headers: {
			Authorization: `OAuth oauth_consumer_key="${process.env.TRELLO_KEY}", oauth_token="${process.env.TRELLO_TOKEN}"`,
		},
	})
	const buffer = await image.buffer()

	// Set response headers
	res.setHeader('content-type', image.headers.get('content-type'))
	res.setHeader('content-length', image.headers.get('content-length'))

	// Send file
	res.send(buffer)
	
})

app.listen(3000, '0.0.0.0')