A Twitter bot that reverses the text it gets from @mentions from a specific user ID.

twitterbot-reversify.js

// A Twitter bot! Experimental!
// Reverses words of text sent to it.
//# node {{f}} # don't forget to add environment vars!

// npm install twit
var Twit = require('twit');

// how many @mentions from the top to fetch, to look for
// TODO: go through many pages of @mentions
// TODO: add since_id for the last tweet this fetched
var COUNT = process.env['COUNT'] || 15;

// Strip out mentions from the produce
// Matches @.... mentions
var mention = /@.+?\s+/g;

// Queue to fire off functions (such as posting Tweets)
// and an interval for when to do so, in milliseconds.
var queue = [];
var INTERVAL = process.env['INTERVAL'] || 15000;

// User ID to filter requests for
// If 0, go find the piece of code and edit it out ;)
var filter_id = parseInt(process.env['USER_ID'], 10);


// Crudely stolen from Underscore.js
var _={};
_.debounce = function(func, wait, immediate) {
  var timeout;
  return function() {
    var context = this, args = arguments;
    var later = function() {
      timeout = null;
      if (!immediate) func.apply(context, args);
    };
    var callNow = immediate && !timeout;
    clearTimeout(timeout);
    timeout = setTimeout(later, wait);
    if (callNow) func.apply(context, args);
  };
};

// Clear the queue - set every pending function to run
// at intervals of #{INTERVAL} * index
function runQueue() {
  console.log('clearing the queue...');
  var item;
  for (var i=0;i<queue.length;i++) {
    setTimeout(queue[i], INTERVAL*i);
    console.log('added queue item to run: ' + queue[i] + 
                ' in ms: ' + INTERVAL*i);
  }

  // Clear the queue, we're done here.
  queue = [];
}

// we're calling runq inside the code, make it so it calls at least
// 15s apart
var runq = _.debounce(runQueue, 15000);

// Set up Twit client. 
// Get your keys from:
// https://apps.twitter.com/app/<your app ID>/keys
var T = new Twit({
  consumer_key: process.env['API_KEY'],
  consumer_secret: process.env['API_SECRET'],
  access_token: process.env['ACCESS_TOKEN'],
  access_token_secret: process.env['ACCESS_TOKEN_SECRET']
});

// Get #{count} mentions
T.get('statuses/mentions_timeline', {
    count: COUNT
  },
  function(err, data, response) {

    // we did something wrong, or we're over the limit. hear twitter out
    if (response.statusCode !== 200) {
      if (response.statusCode === 429) {
        console.log('aborting: we hit the rate limit!');
      } else if (response.statusCode === 403) {
        console.log('aborting: unauthorized!');
      } else {
        console.log('aborting: http ' + response.statusCode);
      }
      return;
    }

    // we're in the clear!

    console.log('requests left:', response.headers['x-rate-limit-remaining']);
    
    console.log('requests will reset on', 
      new Date(
        Date.now() + Number(response.headers['x-rate-limit-reset'])/1000));
    
    // Actually go over the entries
    for (var i=0;i<data.length;i++) {

      // Mangle the tweet text
      var reversed = data[i].text.replace(mention, '')
                                 .split(' ')
                                 .reverse()
                                 .join(' ');

      // Nicely log every Tweet and its reversed text
      console.log('from @' + data[i].user.screen_name + '/'+data[i].user.id);
      console.log('\treversed:', reversed);

      // Create the entire Tweet response
      var status = '@'+data[i].user.screen_name + ' ' + reversed;

      if (data[i].user.id == filter_id) {
        console.log('found a tweet from the filter, posting response');

        // Push the tweet-sending-function into the tweet queue
        queue.push(
          // Create a tweet-sending-function by running a function to
          // return it, taking the tweet content as an argument.
          // Javascript scoping is weird.
          (function(status) {
            // Return a function that calls statuses/update with our
            // tweet text. 
            return function() {
              console.log('posting tweet!');

              // Call statuses/update with our tweet text.
              // Then, handle possible statuses, and stop.
              T.post('statuses/update', { 
                'status': status }, function(err, data, response) {
                  if (response.statusCode == 403) {
                    console.log('already posted that tweet. bye');
                  } else if (response.statusCode == 200) {
                    console.log('yay! all worked out after all!');
                  } }); }; })(status));
        // Clear the queue, if it hasn't been cleared in 15 seconds.
        runq();
      }
    }
});