job.js

var model = require('./model');
var config = require('./config');
var request = require('request');

var LIMIT = 20;

setTimeout(() => process.exit(), 10000); // the process quits after 10 seconds

function fetchMessageContent(msgs, callback) {
  var url = 'https://slack.com/api/channels.list?token=' + config.SLACK_TOKEN;
  //console.log(url);
  request.get(url, { json: true }, (err, res, body) => {
    //console.log(err, typeof body, body);
    var channels = {};
    body.channels.forEach(c => {
      channels[c.id] = c;
    });
    callback(err, msgs.map(m => Object.assign(m, {
      channelName: channels[m.channel].name
    })));
  });
}

console.log('find...');
model.Message.find({ broadcasted: { $ne: true } }).sort({ votes: -1 }).limit(LIMIT).exec(function(err, msgs){
  console.log('find=>', err || msgs);
  fetchMessageContent(msgs, function(err, messages){

    if (messages.length === 0) {
      config.bot.postMessageToChannel(config.DIGEST_CHANNEL, 'Sorry, no new messages with ' + config.REACTION_NAME + ' this time... :\'-(', {
        unfurl_links: true
      });
    } else {
      messages.forEach(function(msg){
        // syntax: <nb_votes> :balloon: <URL>
        var url = 'https://' + config.SLACK_NAME + '.slack.com/archives/' + msg.channelName + '/p' + msg.id.replace('.', '');
        var digestLine = msg.votes + ' :' + config.REACTION_NAME + ': ' + url;
        console.log(digestLine); // TODO
        // display in the #gen-bot channel
        config.bot.postMessageToChannel(config.DIGEST_CHANNEL, digestLine, {
          unfurl_links: true
        });
      });

      // TODO: send digest to admin, then allow admin to edit it before sharing it publicly
      // config.bot.postMessageToUser(config.ADMIN_USERNAME, digest, { 'slackbot': true, icon_emoji: ':cat:' });
      // will post the user, from "Gem Bot" (instead of slack's slackbot channel)

      // mark messages
      const ids = messages.map(m => m.id);

      // prevent a message from being digested twice
      model.Message.update({ id: { $in : ids } }, { $set: { broadcasted: true } }, { multi: true }, (err, res) => {
        err && console.error(err);
      });
    }
  });
});