diversity.volt.link/index.js

require('dotenv').config()

// const isDevEnvironment = process.env.environment === 'dev' || false
const path = require('path')
const url = require('url')

const http = require('http')

const express = require('express')
const rateLimit = require('express-rate-limit')

// const { fetch } = require('cross-fetch')

const fs = require('fs')

const static_files_path = path.join(__dirname, './frontend/')

// volt_team_api_key

function checkOrigin(origin){
  return (
    typeof origin === 'string'
    && (
      origin === 'volt.link'
      || origin.endsWith('://volt.link')

      // allow from subdomains
      || origin.endsWith('.volt.link')

      // allow for localhost
      || origin.endsWith('localhost:3000')
      || origin.endsWith('localhost:4000')
      || origin.endsWith('0.0.0.0:3000')
      || origin.endsWith('0.0.0.0:4000')
      || origin.endsWith('localhost:19006')
    )
  )
}

// function getUserLocales(){
//     const localesByCounty = {
//       de: ['de'],
//     }
//   // https://get.geojs.io/v1/ip/geo/{ip address}.json
// }

const app = express()

// set up rate limiter: maximum of 100 requests per minute
app.use(rateLimit({
  windowMs: 1 * 60 * 1000, // 1 minute
  max: 1000, // Limit each IP to 1000 requests per `window` (here, per 1 minute)
  standardHeaders: true, // Return rate limit info in the `RateLimit-*` headers
  legacyHeaders: false, // Disable the `X-RateLimit-*` headers
})) // apply rate limiter to all requests

app.use(express.json())

app.use(function (req, res, next) {
  // const origin = req.get('origin')
  const origin = req.header('Origin')
  if (checkOrigin(origin)) {
    req.is_subdomain = true
    req.origin = origin
    res.setHeader('Access-Control-Allow-Origin', origin)
    res.setHeader('Access-Control-Allow-Credentials', true)
  } else {
    req.is_subdomain = false
  }

  next()
})

app.options("/*", function (req, res, next) {
  // correctly response for cors
  if (req.is_subdomain) {
    res.setHeader('Access-Control-Allow-Origin', req.origin)
    res.setHeader('Access-Control-Allow-Credentials', true)
    res.setHeader('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS')
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization, Content-Length, X-Requested-With')
    res.sendStatus(200)
  } else {
    res.sendStatus(403)
  }
})

app.get('/login', (req, res) => {
  res.redirect(url.format({
    pathname: '/auth/google',
    query: req.query,
  }))
})

function showClient(res, blocks = []) {
  // send index file to show client
  const index_file_path = static_files_path + '/index.html'

  // load index file
  fs.readFile(index_file_path, 'utf8', function (err, index_file) {
    if (err) {
      console.error(err)
      res.sendStatus(500)
    } else {
      let title = 'VoltLink'
      let description = 'VoltLink is an information-hub about Volt Europa.'
      let coverphoto_url = ''

      if (blocks.length > 0) {
        const block = blocks[0]

        if (
          block
          && block.hasOwnProperty('properties')
          && typeof block.properties === 'object'
          && block.properties !== null
        ) {
          if (
            block.properties.hasOwnProperty('text')
            && typeof block.properties.text === 'string'
            && block.properties.text.length > 0
          ) {
            title = block.properties.text
            description = ''
          }

          coverphoto_url = getImageUrl(block.properties.coverphoto)
          if (!coverphoto_url) {
            coverphoto_url = getImageUrl(block.properties.icon)
          }
        }

        if (coverphoto_url !== '') {
          coverphoto_url = `https://api.volt.link/download_url?f=jpg&w=1000&h=1000&url=${encodeURIComponent(coverphoto_url)}`
        }
      }

      const __SERVER_DATA__ = "JSON.parse(" + JSON.stringify(JSON.stringify({ preloaded_blocks: blocks })) + ")" // First stringify is to get arrays and objects represented correctly. Second stringify+parse to ease parsing of js code on the client.

      index_file = index_file
        .replace(/__META_TITLE__/g, title)
        .replace(/__META_DESCRIPTION__/g, description)
        .replace(/__META_COVERPHOTO__/g, coverphoto_url)
        .replace(/__SERVER_DATA__/g, __SERVER_DATA__)

      res.send(index_file)
    }
  })

  // The client needs to check if the block exists OR if a error page should be shown.
  // AND the client should to correct the slug if it's wrong.
  // (TODO: There currently is no function to find the correct slug from an id.)
}

app.get('/', async function (req, res, next) {
  showClient(res) // call showClient to replace the default meta infos (__META_TITLE__, ...)
})

app.use(express.static(static_files_path))

app.get('*', function (req, res, next) {
  showClient(res) // show index.html as a fallback
})

const port = 4007
const host = '0.0.0.0' // Uberspace wants 0.0.0.0
http.createServer(app).listen({ port, host }, () =>
  console.info(`
    🚀 Server ready
    For uberspace: http://${host}:${port}/
    For local development: http://localhost:${port}/
  `)
)