app.js

const express = require('express')
const bodyParser = require('body-parser')
const uuidv4 = require('uuid/v4')

const app = express()

const images = {}

// This is middleware that lets you get the post body in your endpoint handlers below
app.use(bodyParser.json())

// POST to the app with a dataUri in the post body
app.post('/', ({body: {dataUri}}, res) => {
  // Generate a token that looks like an image
  const token = `${uuidv4()}.png`
  
  // Store the item in memory
  images[token] = dataUri
  
  // Remove the item after 10 minutes
  setTimeout(() => { delete images[token] }, 1000 * 60 * 10)
  
  // Give back the token
  res.end(token)
})

// GET from the app with any token
app.get('/:token', (req, res) => {
  // Fetch the token, or undefined if it doesn't exist
  res.end(images[req.params.token])
})

app.listen(3000, () => console.log('Image Store activated on port 3000'))