frontend/middleware/locals.js

const config = require("../config")

module.exports = (req, res, next) => {
  if (res.marko) {
    res.markoAsync = async(template, input) => {
      const locals = Object.assign({}, (res.locals || {}), input)

      try {
        for (const key in locals) {
          const value = locals[key]
          if (value instanceof Promise) {
            locals[key] = await value
          }
        }
        
        if (locals.user.permissions != null) {
          locals.user.permissions = await locals.user.permissions
        }
      } catch(err) {
        if (JSON.stringify(err) === "{}") {
          return next(err)
        }
        
        return res.status(404).json(err)
      }

      return res.marko(template, locals)
    }
  }

  if (req.user) {
    res.locals.user = {
      loggedIn: true,
      name: req.user._json.name,
      permissions: getPermissions(req.user._json.name),
    }
  } else {
    res.locals.user = {
      loggedIn: false,
    }
  }

  next()
}

function getPermissions(user) {
  return fetch(config.graphqlEndpoint, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "Authorization": `Bearer ${generateToken(user, ["member"])}`,
    },
    body: '{"query":"query { token { user { permissions } } }", "variables": {}}',
    credentials: "include",
  }).then(res => {
    return res.json()
  }).then(json => {
    return json.data.token.user.permissions
  }).catch(err => {
    console.error(err)
    return []
  })
}

const jwt = require("jsonwebtoken")
/**
 * @param {string} user 
 * @param {string[]} permissions 
 */
function generateToken(user, permissions) {
  return jwt.sign({user, permissions, exp: Math.floor((Date.now() / 1000) + 1200)}, config.backend.secret, {header: {kid: config.backend.kid}})
}