Making a twitter bot is one of the many use cases of using the Twitter API. A bot can be used to enhance your business, assist customers through automated replies, automate retweets for specific terms, and a lot more.
This article is about how I created The Data Science Bot using Node.js.

Table Of Contents

1. Apply for Twitter developer account
2. Create app on twitter
3. Setup dev environment
4. Write code in nodejs
5. Deploy to heroku
6. How to avoid duplication of retweets

Step 1: Apply for Twitter Developer Account

This is the most important and perhaps the most difficult step according to me.

• Login into Twitter
• Go to developers.twitter.com and click on 'Apply for a Developer account'
• Select the type of application i.e. student/business/hobbyist, etc.
• Mention the purpose of your application. Be as specific as you can over here.

Make sure you have read the Developer Agreement and Policy, Automation rules and The Twitter Rules thoroughly before applying.

Failing to meet these conditions will cause your application to be rejected

Read the full article on How to apply for a twitter developer Account

Step 2: Create app on twitter

Once your twitter developer account access has been approved.

• Create an APP on apps.twitter.com.
  Fill in the required details.

• Generate API keys. Click on your apps details and navigate to Keys and tokens
  

⚠️ Warning (Don't reveal the API keys in any case).

Step 3: Setup Development Environment

Make sure you have Node.js and npm installed on your PC.

For Ubuntu, install using the following commands

sudo apt install nodejs
sudo apt install npm

For other distributions, click here for installation instructions.

Create a directory named your-botname.
In my case, I have named it the-datascience-bot.

To initialize the git environment and install the package twit using npm, enter the following commands inside the your-botname directory:

Congratulations! You have successfully set up your Node.js DEV environment 🎉🎉

Step 4: Code

• Firstly, we have to authenticate twit. To do this, we will link our twitter app and code using the generated API keys.

Create a file named config.js.
Put the following code in your config.js file

config.js

Put your keys copied from your twitter apps dashboard.

• Next, we write the code for the bot in a file bot.js.

Here is the code.

bot.js

const config = require('./config')
const twit =  require('twit')

const T = new twit(config)

function retweet(searchText) {
    // Params to be passed to the 'search/tweets' API endpoint
    let params = {
        q : searchText + '',
        result_type : 'mixed',
        count : 25,
    }

    T.get('search/tweets', params, function(err_search, data_search, response_search){

        let tweets = data_search.statuses
        if (!err_search)
        {
            let tweetIDList = []
            for(let tweet of tweets) {
                tweetIDList.push(tweet.id_str);

                //more code here later...
            }

            // Call the 'statuses/retweet/:id' API endpoint for retweeting EACH of the tweetID
            for (let tweetID of tweetIDList) {
                T.post('statuses/retweet/:id', {id : tweetID}, function(err_rt, data_rt, response_rt){
                    if(!err_rt){
                        console.log("\n\nRetweeted! ID - " + tweetID)
                    }
                    else {
                        console.log("\nError... Duplication maybe... " + tweetID)
                        console.log("Error = " + err_rt)
                    }
                })
            }
        }
        else {
            console.log("Error while searching" + err_search)
            process.exit(1)
        }
    })
}

// Run every 60 seconds
setInterval(function() { retweet('#DataScience OR #DataVisualization'); }, 60000)

Let's break it down.

• We initialize the twit object using our configuration details from config.js
• The retweet function first calls the search/tweets API endpoint for the given search query. In my case, it is '#DataScience OR #DataVisualization'
• We pass the following parameters to search API
  • q: The search query
  • result_type: 'mixed' for latest as well as popular older tweets
  • count: number of tweets to retrieve at once
• The retrieved JSON object has the list of tweets having either #DataScience or #DataVisualization in it.

-We then pass each of the tweet IDs to the statuses/retweet/:id API endpoint, which retweets the tweet.

Detailed API reference guides for Search and Retweet.

Test the bot locally using the following command:

node bot.js

Your Twitter timeline should show the retweets.

Try debugging on the console if it doesn't work.

Step 5: Deploy to Heroku

• Create an account on Heroku
• Create an app named 'your-botname' on Heroku

Make sure the name of your local project directory is exactly the same as your Heroku project name.

• Install heroku-cli on your pc

If you have an Ubuntu/Debian based distribution, then use the following command to install heroku-cli

curl https://cli-assets.heroku.com/install-ubuntu.sh | sh

For other environments, the installation instructions can be found here

• Create a file named 'Procfile' having the following code

Procfile

worker: node bot.js

• Login to heroku CLI

$ heroku login

This will open a login link on heroku, where you have to enter your password.

• Deploy to Heroku using these commands

One last step

Start the worker dyno on Heroku.
Go to dashboard.heroku.com/apps and click on your bot app.

Then, click on configure Dynos

Start the worker dyno and click on confirm

And your bot is Ready! 🎉🎉

Step 6: How to avoid duplication of retweets

Add the following code in the for loop where we wrote
//more code here later..

Check duplication

Then outside the loop -

// Utility function - Gives unique elements from an array
function onlyUnique(value, index, self) { 
    return self.indexOf(value) === index;
}

// Get only unique entries
tweetIDList = tweetIDList.filter( onlyUnique )

The utility function onlyUnique can be written outside the retweet function as well.

This will let our bot avoid duplicate retweets.

Short explanation of the above code

• Each tweet has a unique property id_str.
  If you retweet someone's tweet, it has a different id_str.

• The search API finds both the original tweet and the retweeted ones.

• When we call the statuses/retweet/:id API endpoint, it retweets all of them.

• To a novice Twitter user, it looks like your bot has retweeted the same stuff two or more times.

Something like this 👇

• If tweet text starts with "RT @" then it is a retweeted tweet, with a different id_str than the original. We take the id_str of the original tweet and filter duplicates using the onlyUnique function

There are a lot more things you can do with the API. Check out the API reference(https://developer.twitter.com/en/docs/api-reference-index) for more details.

Source Code -

The full source code can be accessed here

The Data Science Bot 🤖

The bot retweets tweets having hashtags #DataScience and #DataVisualization

Here is the link to my bot https://twitter.com/datasciencebot_

Alright, that's it!

This was my first tech article on the Developer community.
Any feedback would be greatly appreciated!

Thanks for reading! 😊