Node.js Slack Bot to Query Channel History

app.js

// We're using the slack-client library
var SlackClient = require('slack-client');

// Automatically reconnect after an error response from Slack.
var autoReconnect = true;

// Put your bot API token here
var token = "YOUR TOKEN HERE";

// Put your slack team name here
// We'll use this when piecing together our API call
var team = "YOUR TEAM HERE";

var slackClient = new SlackClient(token, autoReconnect);
 
// Track bot user, for detecting the bot's own messages
var bot;

// We'll define our own custom API call to get channel history
// See the note for step 10 above
var XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;

var getChannelHistory = function() {
  this.get = function(family, value, callback) {
  var xhr = new XMLHttpRequest();
  // This builds the actual structure of the API call using our provided variables
  var url = "https://" + team + ".slack.com/api/" + family + ".history?token=" + token + "&channel=" + value;
  xhr.onreadystatechange = function() { 
    if (xhr.readyState == 4 && xhr.status == 200)
      callback(xhr.responseText);
    }
    xhr.open("GET", url, true); 
    xhr.send();
  }
}

// Tell us when the app is running
slackClient.on('loggedIn', function(user, team) {
  bot = user;
  console.log("Logged in as " + user.name
    + " of " + team.name + ", but not yet connected");
});

slackClient.on('open', function() {

  // Find out which public channels the bot is a member of
  var botChannels = Object.keys(slackClient.channels)
    .map(function (k) { return slackClient.channels[k]; })
    .filter(function (c) { return c.is_member; })
    .map(function (c) { return c.name; });

  // Find out which private channels the bot is a member of
  var botGroups = Object.keys(slackClient.groups)
    .map(function (k) { return slackClient.groups[k]; })
    .filter(function (g) { return g.is_open && !g.is_archived; })
    .map(function (g) { return g.name; });
 
  // Tell us when the bot is connected
  console.log('Connected as ' + slackClient.self.name + ' of ' + slackClient.team.name);
 
  // Print our list of channels and groups 
  // that we found above in the console
  if (botChannels.length > 0) {
    console.log('You are in these public channels: ' + botChannels.join(', '));
  } else {
    console.log('You are not in any public channels.');
  }
 
  if (botGroups.length > 0) {
     console.log('You are in these private channels: ' + botGroups.join(', '));
  } else {
    console.log('You are not in any private channels.');
  }
});

// What to do when a message is posted 
// to one of the bot's channels--
// This is the real meat of our app
slackClient.on('message', function(message) {
  // Ignore the bot's own messages
  if (message.user == bot.id) return;
 
  // Get the current channel, 
  // so we know where to post messages to later
  var channel = slackClient.getChannelGroupOrDMByID(message.channel);

  // We're wrapping our functionality in an IF statement
  // to only respond to messages directed at this bot
  if (message.type === 'message' && message.text.length >= 0 && message.text.indexOf(slackClient.self.id) > -1) { 
    // Take the message that was sent to the bot
    // And split off just the relevant bit
    // See the note for step 5 above
    searchString = message.text.split(" ").pop();

    // Print out the name of the channel the bot is analyzing
    console.log("Attempting to query channel: " + searchString);
    
    // Retrieve the requested channel object
    // using functions from the slack-client library
    var myChannel = slackClient.getChannelGroupOrDMByName(searchString);

    // Check to verify if we've returned a valid channel
    if (typeof myChannel != "undefined") {      
      // Get the channel ID from the channel object
      var myChannelID = myChannel['id'];

      // Determine whether this is a public 
      // or private channel (i.e., group)
      // by looking at the data in the channel object
      if (myChannel.getType() == 'Group') {
        family = "groups";
      } else {
        family = "channels";
      };

      // Get the message history for the channel
      // using our custom API call
      history = new getChannelHistory();
      history.get(family, myChannelID, function(response) {
        // Now that we have our messages, 
        // let's parse them to make them readable
        json = JSON.parse(response);

        // The history object had a few children, 
        // so we're just pulling out the "messages" child
        mymessages = json['messages'];

        // Create an array to hold our filtered list of messages
        var unresolved = [];

        // Filter for messages that don't have reactions
        for (var i = 0; mymessages.length > i; i++) {
          // For each message, get the reactions (if any)
          var msgStatus = mymessages[i]['reactions'];

          // If the message has no reactions...
          if (typeof msgStatus == "undefined") {
            // ...add the message to our array
            unresolved.push(mymessages[i].text);
          }
        };

        // Once we've finished looping through all the messages
        // count how many didn't have reactions, for logging
        var myCount = unresolved.length;

        // Combine our array of unresolved messages into one line
        // so the bot can send just one message to slack
        var list = unresolved.join("\n");

        // Print out our final, single message to slack
        channel.send("Your Unresolved Items: \n" + list);

        // Print to the console that the query was successful,
        // and how many unresolved messages were found
        console.log("Query successful! Returned " + myCount + " items")
      });

    // If the message to the bot is formatted wrong, then do this:
    } else {
      // Tell the user how to format their request correctly
      channel.send("I'm sorry, I don't understand. I need you to end your sentence with a valid channel name of which I am a member.");

      // Also print to the console that the query failed, and give some helpful pointers
      console.log("Query FAILED.");
      console.log("Did your sentence end with a valid channel name?");
      console.log("Have you invited TaskBot to join the requested channel?");
    }
  }; 
});

slackClient.login();