A part of Tipple. (Command parser. Licensed under MIT.)

server.ts

import express = require('express');
import twit = require('twit');
import report_queue = require('./report-queue');
import utils = require('./utils');
import tip = require('./tip');

const bodyParser = require('body-parser');
const app = express();
const crypto = require('crypto');
const config = require("./config.json");

//app.set('port', (process.env.PORT || 8080));
app.set('port', 8080);
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

// For health checks by load-balancers.
app.get('/', (_request: express.Request, response: express.Response) => {
  response.status(200);
  response.send('"healthy"');
});

// For challenge response check (CRC)
app.get(config.expressWatchPath, (request, response) => {
  const crc_token = request.query.crc_token
  if (crc_token) {
    const hash = crypto.createHmac('sha256', config.TWITTER_CONSUMER_SECRET).update(crc_token).digest('base64');
    console.log(`receive crc check. token=${crc_token} responce=${hash}`);
    response.status(200);
    response.send({
      response_token: 'sha256=' + hash
    });
  } else {
    const errorMessage = 'Error: crc_token missing from request.';
    response.status(400);
    response.send(errorMessage);
    console.error(errorMessage);
  }
});

const isSelfTweet = (for_user_id: string, tweet: twit.Twitter.Status) => {
  if (for_user_id === tweet.user.id_str) {
    console.log(`Tweeted by botself: TweetID ${tweet.id_str}.`);
    return false;
  } 
  return true;
};

const randomTail = () =>
  "....".substring(Math.random() * 4) + "!!!".substring(Math.random() * 3)

const parseTweet = (tweet: twit.Twitter.Status) => {
  if (!tweet.text) {
    console.warn(`Can't parse the tweet.text: ${tweet}`);
    return;
  }
  const parse = tweet.text.match(/^\s*(@\S+\s+)*(.*)$/);
  if (!parse || !parse[2]) {
    console.warn(`Can't parse the tweet: ${tweet.text}`);
    return;
  }
  const cmd = parse[2] as string;

  switch (true) {
    case /^TIP(\s.*)?$/i.test(cmd):
      {
        const match = cmd.match(/TIP\s+@(.*)\s+(([1-9]\d*|0)(\.\d+)?).*$/i);
        if (match != null) {
          tip
            .doIt(tweet.user.id_str, match[1], +(match[2]))
            .then(() => {
              if (match[1] === 'tipxrp') {
                report_queue.reply(`@${tweet.user.screen_name} Thank you for your donation${randomTail()}!`, tweet.id_str);
              } else {
                report_queue.reply(`@${tweet.user.screen_name} Sent ${match[2]}XRP to @${match[1]}${randomTail()}`, tweet.id_str);
              }
            })
            .catch ((error: any) =>
              report_queue.reply(`@${tweet.user.screen_name} Fail to send. (msg: ${error.message})`, tweet.id_str));
        } else {
          report_queue.reply(`@${tweet.user.screen_name} Couldn't parse your command${randomTail()}`, tweet.id_str);
          console.warn(`Can't parse the cmd tweet: ${cmd}`);
        }
      }
      break;

    case /^GIVEME(\s.*)?$/i.test(cmd):
      report_queue.reply(`@${tweet.user.screen_name} Faucet will not be implemented. Sorry${randomTail()}`, tweet.id_str);
      break;

    case /BALANCE(\s.*)?$/i.test(cmd):
      utils
        .getBalance(tweet.user.id_str)
        .then ((balance: any) =>
          report_queue.reply(`@${tweet.user.screen_name} You have ${balance}XRP${randomTail()}`, tweet.id_str));
      break;

    case /^DEPOSIT(\s.*)?$/i.test(cmd):
      utils
        .getWalletAddress(tweet.user.id_str)
        .then (address =>
          report_queue.reply(`@${tweet.user.screen_name} Your XRP address/desination tag is ${address[0]} / ${address[1]}${randomTail()}`, tweet.id_str));
        break;

    case /^WITHDRAW(\s.*)?$/i.test(cmd):
      {
        const match = cmd.match(/^WITHDRAW\s+(([1-9]\d*|0)(\.\d+)?)\s+((r\S{33})(\?dt=(\d+))?)(\s.*)?$/i);
        if (match != null) {
          utils
            .requestWithdraw(tweet.user.id_str, match[5], +(match[1]), match[7] ? +(match[7]) : 0)
            .then(result =>
              report_queue.reply(`@${tweet.user.screen_name} Accepted your withdrawal request : ${result[0]}XRP (incl. tx fee ${result[1]})${randomTail()}`, tweet.id_str))
            .catch(error => {
              report_queue.reply(`@${tweet.user.screen_name} Error in your withdrawal. (msg: ${error.message})${randomTail()}`, tweet.id_str);
              console.error(error);
              });
        } else {
          report_queue.reply(`@${tweet.user.screen_name} Couldn't parse your command${randomTail()}`, tweet.id_str);
          console.warn(`Can't parse the cmd tweet: ${cmd}`);
        }
      }
      break;

    case /^GETCODE(\s.*)?$/i.test(cmd):
      report_queue.reply(`@${tweet.user.screen_name} Invitation program will not be implemented. Sorry${randomTail()}`, tweet.id_str);
      break;

    case /^INVITED(\s.*)?$/i.test(cmd):
      report_queue.reply(`@${tweet.user.screen_name} Invitation program will not be implemented. Sorry${randomTail()}`, tweet.id_str);
      break;

    //TODO: implment
    case /^FOLLOWME(\s.*)?$/i.test(cmd):
//    robot.logger.info "followed ${tweet.user.screen_name}!"
//    console.dir msg.message.user
//    robot.adapter.join msg.message.user
      break;

    case /^HELP(\s.*)?$/i.test(cmd):
      console.log(`Tweet: test comand.`);
      report_queue.reply(`@${tweet.user.screen_name} Please open https://tipxrp.monaco-ex.org/ ${randomTail()}`, tweet.id_str);
      break;

    default:
      console.log(`Tweet: ${tweet.text}`);
      break;
  }
};

app.post(config.expressWatchPath, (request, response) => {
  const tweet_create_events = request.body.tweet_create_events;
  if (tweet_create_events) {
    tweet_create_events.filter((x: twit.Twitter.Status) => isSelfTweet(request.body.for_user_id, x))
      .map((x: twit.Twitter.Status) => parseTweet(x));
  } else {
    console.log(`Skipped: ${JSON.stringify(request.body, null, "  ")}`);
  }
  console.log('====');

  response.send('200 OK');
});

require('./cron').doIt();

app.listen(app.get('port'), function () {
  console.log('Node app is running on port', app.get('port'));
});