mailgun.js

const { json, send } = require('micro');
const cors = require('micro-cors')();
const fetch = require('node-fetch');
const parse = require('urlencoded-body-parser');
const crypto = require('crypto');
const Mailgun = require('mailgun-js');

const db = require('../../models/db');
const el = require('../../models/email-list');
const dl = require('../../models/dl-item');

const email = require('../../email-template');

const secret = process.env.SECRET;
const mg_api_key = process.env.MAILGUN_API;
const mg_url = process.env.MAILGUN_URL;
const mg_from = process.env.MAILGUN_FROM;
const download_url = process.env.DOWNLOAD_URL;

module.exports = cors(async function (req, res){
  
  //parse body

  try{
    data = await parse(req);
  }
  catch(e){
    res.statusCode = 500;
    res.end(JSON.stringify(e));
    return;
  }
  
  //verify recaptcha

  var grec = {
    "secret": secret,
    "response": data["g-recaptcha-response"]
  };

  var verifyURL = `https://www.google.com/recaptcha/api/siteverify?secret=${secret}&response=${data["g-recaptcha-response"]}`;

  // strange hybrid await + .then promise handling is for promise debugging only - fix now that it's working
  
  const v = await fetch(verifyURL, {
    method: 'post',
    body:    JSON.stringify(grec),
    headers: { 'Content-Type': 'application/json' },
  })
  .then(res => res.json())
  .then(json => json);

  if(process.env.DEBUG){
    console.log(v);
  }
  else if(!v.success){
    console.log(v);
    return await send(res, 400, JSON.stringify(v));
  }

  // external mailing list DB update
  
  q = await el.find({ email: data.email.toLowerCase()});
  if(! (q && q.length)){
    try{
      el_item = new el({ email: data.email.toLowerCase(), download: "printing ebook", count: 1 });
      new_el_item = await el_item.save();
    }
    catch(e){
      console.log(e);
    }
  }else{
    q[0].count = q[0].count + 1;
    el_item = await q[0].save();
  }

  // create download key used for secure expiring AWS S3 link later
  
  code = crypto.createHash('md5').update(data.email.toLowerCase() + secret + (new Date()).toISOString()).digest("hex");
  try{
    dl_item = new dl({ code: code, email: data.email.toLowerCase(), download: "printing ebook", count: 5 });
    new_dl_item = await dl_item.save();
  }
  catch(e){
    console.log("Duplicate MD5 Hash: " + code);
    return await send(res, 500, JSON.stringify(e));
  }

  // send fake link reference via email with mailgun

  var mg = new Mailgun({apiKey: mg_api_key, domain: mg_url});

  console.log(mg);

  var data = {
    from: mg_from,
    to: data.email,
    subject: 'Hello from LPFA',
    html: email(download_url + dl_item.code)
  }

  // strange hybrid await hybrid only to debug promise - fix at some point now that it's working.
  const p = await mg.messages().send(data).then(function (d) {
    console.log("MAILGUN FINISHED");
    console.log(d);
  }, function (err) {
    console.log("got an error: ");
    console.log(err);
    return err; 
  });
  
  // remove now that everything is working

  console.log("MAILGUN AFTER... PROBLEM WITH PROMISE?");
  console.log(p);
  
  if (p) {
    await send(res, 500, JSON.stringify(p));
  }
  else{
    await send(res, 200, JSON.stringify(data));
  }
});