Build a Slack Bot using Node.js

Build a Slack Bot using Node.js

I decided to build a Slack Bot using Node.js that anyone at work

Table of Contents

  1. Prerequisites
  2. Installing Node and NPM
  3. Initializing our Project and Installing Slackbots.js
  4. Creating a New Slack bot
  5. Building our Bot
  6. Making Your Slack Bot Reply
  7. Running your Slack bot
  8. Conclusion
  9. Resources

The logo for Slack!

In this tutorial, we will be learning how to build a simple Slack bot that replies back a random greeting when you say "hi" or "hello". The bot will be written in JavaScript in conjunction with Node.js!

Here's a look at the bot in action:

A look at our finished Slack bot

Before we get started, please ensure you meet the prerequisites for this tutorial:

Prerequisites
  • Since the bot is written in JavaScript, basic knowledge of JavaScript would be helpful
  • A Slack account and active Slack instance to deploy your bot on
Installing Node and NPM

To install the necessary software for this project, we will first need Node.js, a JavaScript runtime.

  1. Visit the official Node.js website to get the installer.
  2. After it downloads, run the installer until the end.
  3. Restart your computer to ensure the changes can take effect.

The Node.js installer.

The Node.js installer should have also installed NPM for you. To confirm that you have installed both properly, you'll need to open Windows Command Prompt if you're on Windows, or Terminal if you're on Mac or Linux.

To check if you installed node:

 node -v

To check if you installed NPM:

 npm -v

If both of these commands return a version number, you're good to go.

Initializing our Project and Installing Slackbots.js

Create a folder anywhere you'd like to serve as the root directory for your bot. Navigate to that folder and initialize a new project by running

   npm init

Feel free to enter in whatever information you'd like. After that finishes running, you will be left with a file called package.json.

Now, to simplify our interactions with Slack's Real Time Messaging API, we will be using the Slackbots.js library. To install Slackbots.js for use in our project, run the installation command:

 npm install slackbots --save

We are now ready to use Slackbots.js in our code!

Creating a New Slack bot

Let's register a new bot on our slack instance. Head on over to:

 https://instance.slack.com/services/new/bot

Replace instance with the name of your Slack instance. Once here, give your bot a name. We'll call our bot Slacky.

Creating a new Slack bot.

After you hit Add bot integration, you'll be provided with your bot's API token. You'll need this later on so save this somewhere. Additionally, you can also change the name of your bot, upload an icon, and set what channels your bot will operate inside.

The Slack bot settings page.

Building our Bot

In the same directory that your package.json lives in, create a new file called index.js. This file will serve as the code for your bot.

The project's folder structure.

Let's create a bot using Slackbots.js:

var SlackBot = require("slackbots");
var bot = new SlackBot({
    token: "",
    name: "Slacky"
});

That's all we need to have a functional bot. Fill in the token value with the API token you got earlier and you're good to go. To test that this all works, let's make the bot send us a message upon start-up:

var SlackBot = require("slackbots");
var channel = "general";

var bot = new SlackBot({
    token: "",
    name: "Slacky"
});

bot.on("start", function() {
    bot.postMessageToChannel(channel, "Hello world!");
    console.log("Hello world!");
});

Our new code has our bot listen on the start event which is fired when a connection to Slack is established. Once the event fires, it will run the provided function. In that function, we tell our bot to send the text Hello world! to the channel you defined in the channelvariable. Finally, we threw in a console.log just for good measure.

Now it's time to run our bot. To do so, simply run your index.js file by running this command at the same directory:

  node index.js

If everything went well, not only should you see Hello world! printed on your console, but if you go to the designated channel on Slack, you should also see your bot having said Hello world!.

Console after running our Slack bot.

Our Slack bot saying hello world in chat.

Making Your Slack Bot Reply

Great so our bot works now, but let us make it do something more than simply say a single line of text upon start up. Let's make our friendly slack bot reply to use a random greeting when we say hi or hello in the same channel that the bot operates in.

To respond to messages we must first listen on the message event.

  bot.on("message", function(data) {

});

However, a "message" according to the Slack API isn't necessarily a message of text sent. A "message" is more like a generic event that could be basically anything. The bottom of this page has a list of all events. Before of this, we must specifically look into events that are the type message, like so:

 bot.on("message", function(data) {
if (data.type !== "message") {
return;
}

    // this event was a text message sent
});

Because we are ignoring events that aren't messages by immediately returning, we can now safely continue on with events that are messages:

bot.on("message", function(data) {
if (data.type !== "message") {
return;
}

    handleMessage(data.text);
});

We're passing in the text contained in the message event to a new function called handleMessage which we will now define. Again, this function should only reply back with a greeting if we said either hello or hi:

function handleMessage(message) {
switch(message) {
case "hi":
case "hello":
sendGreeting();
break;
default:
return;
}
}

Here we are using a switch case statement to precisely match the string sent. This makes it super easy to add more words to trigger a greeting since all you need to do is add another case for it. If the message matched, we call sendGreeting() to send the reply.

With that being said, let's now define sendGreeting():

 function sendGreeting() {
var greeting = getGreeting();
bot.postMessageToChannel(channel, greeting);
}

The function is that simple. First you get the greeting via getGreeting(), set it to a new variable called greeting, and then you send the greeting to the designated channel like before.

The final step left for this bot is to define the getGreeting() function that randomly returns a greeting:

 function getGreeting() {
var greetings = [
"hello!",
"hi there!",
"cheerio!",
"how do you do!",
"¡hola!"
];
return greetings[Math.floor(Math.random() * greetings.length)];
}

We define a greetings array with five greetings, but feel free to add more if you'd like. Then we randomly select an element to return for our bot to reply back with. That's all the work that needs to be done for this!

Running your Slack bot

Let's put all these pieces together to get our friendly bot fully working. The final code for index.js should look something like this:

var SlackBot = require("slackbots");
var channel = "general";

var bot = new SlackBot({
    token: "",
    name: "Slacky"
});

bot.on("start", function() {
    bot.postMessageToChannel(channel, "Hello world!");
});

bot.on("message", function(data) {
    if (data.type !== "message") {
        return;
    }

    handleMessage(data.text);
});

function handleMessage(message) {
    switch(message) {
        case "hi":
        case "hello":
            sendGreeting();
            break;
        default:
            return;
    }
}

function sendGreeting() {
    var greeting = getGreeting();
    bot.postMessageToChannel(channel, greeting);
}

function getGreeting() {
    var greetings = [
        "hello!",
        "hi there!",
        "cheerio!",
        "how do you do!",
        "¡hola!"
    ];
    return greetings[Math.floor(Math.random() * greetings.length)];
}

Save your file and again run this command to run your bot:

Now when you try saying one of the two designated words to trigger a greeting, you should get a reply back from your Slack bot, like so:

Our finished Slack bot in action, Slacky!

Conclusion

In this tutorial, we have seen how we can use Node.js with Slackbots.js to create a very simple Slack bot that replies back a randomized greeting whenever we say hi or helloin chat. Of course, this functionality is just a very basic example intended to help you get started. The potential for your bot is limitless. Since we are using Node.js, you can do things like request data on the background or call other APIs and then have the bot return that information to you seamlessly.

For more information, we highly recommend that you read up on both the documentation for Slackbot.js and the Slack's Real Time Messaging API as well so that you can be even more familiar about just what you can create.

We hope that this tutorial has been helpful to you. If so, please consider sharing this so that others may also get the same benefit.

Thanks for reading! Originally published on https://sabe.io

Top 7 Most Popular Node.js Frameworks You Should Know

Top 7 Most Popular Node.js Frameworks You Should Know

Node.js is an open-source, cross-platform, runtime environment that allows developers to run JavaScript outside of a browser. In this post, you'll see top 7 of the most popular Node frameworks at this point in time (ranked from high to low by GitHub stars).

Node.js is an open-source, cross-platform, runtime environment that allows developers to run JavaScript outside of a browser.

One of the main advantages of Node is that it enables developers to use JavaScript on both the front-end and the back-end of an application. This not only makes the source code of any app cleaner and more consistent, but it significantly speeds up app development too, as developers only need to use one language.

Node is fast, scalable, and easy to get started with. Its default package manager is npm, which means it also sports the largest ecosystem of open-source libraries. Node is used by companies such as NASA, Uber, Netflix, and Walmart.

But Node doesn't come alone. It comes with a plethora of frameworks. A Node framework can be pictured as the external scaffolding that you can build your app in. These frameworks are built on top of Node and extend the technology's functionality, mostly by making apps easier to prototype and develop, while also making them faster and more scalable.

Below are 7of the most popular Node frameworks at this point in time (ranked from high to low by GitHub stars).

Express

With over 43,000 GitHub stars, Express is the most popular Node framework. It brands itself as a fast, unopinionated, and minimalist framework. Express acts as middleware: it helps set up and configure routes to send and receive requests between the front-end and the database of an app.

Express provides lightweight, powerful tools for HTTP servers. It's a great framework for single-page apps, websites, hybrids, or public HTTP APIs. It supports over fourteen different template engines, so developers aren't forced into any specific ORM.

Meteor

Meteor is a full-stack JavaScript platform. It allows developers to build real-time web apps, i.e. apps where code changes are pushed to all browsers and devices in real-time. Additionally, servers send data over the wire, instead of HTML. The client renders the data.

The project has over 41,000 GitHub stars and is built to power large projects. Meteor is used by companies such as Mazda, Honeywell, Qualcomm, and IKEA. It has excellent documentation and a strong community behind it.

Koa

Koa is built by the same team that built Express. It uses ES6 methods that allow developers to work without callbacks. Developers also have more control over error-handling. Koa has no middleware within its core, which means that developers have more control over configuration, but which means that traditional Node middleware (e.g. req, res, next) won't work with Koa.

Koa already has over 26,000 GitHub stars. The Express developers built Koa because they wanted a lighter framework that was more expressive and more robust than Express. You can find out more about the differences between Koa and Express here.

Sails

Sails is a real-time, MVC framework for Node that's built on Express. It supports auto-generated REST APIs and comes with an easy WebSocket integration.

The project has over 20,000 stars on GitHub and is compatible with almost all databases (MySQL, MongoDB, PostgreSQL, Redis). It's also compatible with most front-end technologies (Angular, iOS, Android, React, and even Windows Phone).

Nest

Nest has over 15,000 GitHub stars. It uses progressive JavaScript and is built with TypeScript, which means it comes with strong typing. It combines elements of object-oriented programming, functional programming, and functional reactive programming.

Nest is packaged in such a way it serves as a complete development kit for writing enterprise-level apps. The framework uses Express, but is compatible with a wide range of other libraries.

LoopBack

LoopBack is a framework that allows developers to quickly create REST APIs. It has an easy-to-use CLI wizard and allows developers to create models either on their schema or dynamically. It also has a built-in API explorer.

LoopBack has over 12,000 GitHub stars and is used by companies such as GoDaddy, Symantec, and the Bank of America. It's compatible with many REST services and a wide variety of databases (MongoDB, Oracle, MySQL, PostgreSQL).

Hapi

Similar to Express, hapi serves data by intermediating between server-side and client-side. As such, it's can serve as a substitute for Express. Hapi allows developers to focus on writing reusable app logic in a modular and prescriptive fashion.

The project has over 11,000 GitHub stars. It has built-in support for input validation, caching, authentication, and more. Hapi was originally developed to handle all of Walmart's mobile traffic during Black Friday.

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A Beginner Guide To Node.js (Basic Introduction To Node.js)

Node.js is a very popular javascript free and open source cross-platform for server-side programming built on Google Chrome’s Javascript V8 Engine. It is used by thousands of developers around the world to develop mobile and web applications. According to StackOverflow survey, Node.js is one of most famous choice for building the web application in 2018.

Introduction

Node.js is a very popular javascript free and open source cross-platform for server-side programming built on Google Chrome’s Javascript V8 Engine. It is used by thousands of developers around the world to develop mobile and web applications. According to StackOverflow survey, Node.js is one of most famous choice for building the web application in 2018.

In this article, you will gain a deep understanding of node, learn how node.js works and why it is so popular among the developers and startups. Not In startup even big companies like eBay, Microsoft, GoDaddy, Paypal etc.

Why is Node.js so much popular

It is fast very fast

It’s a javascript runtime built on google chrome javascript v8 engine which means both node js and js executed in your browser running in the same engine that makes it very fast in comparison to any other server-side programming language.

It uses event-driven and non-blocking model

Node.js uses the event-driven, non-blocking I/O model that makes it very lightweight and efficient.
Now let’s understand the above statement in more details. Here I/O refers to Input /Output.

Event Driven Programming is a paradigm in which control flow of any program is determined by the occurrence of the events. All these events monitor by the code which is known as an event listener. If you are from javascript background then most probably you know what is event-listeners. In short, event-listener is a procedure or function that waits for an event to occurs. In javascript, onload, onclick, onblur most common event-listener.

**Blocking I/O **takes time and hence block other function. Consider the scenario where we want to fetch data from the database for two different users. Here we can not get the data of the second user until we did not complete the first user process. Since javascript is a single threaded and here we would have to start a new thread every time we want to fetch user data. So here Non-Blocking I/O parts come in.

Example of Blocking I/O operation

<span class="hljs-keyword">const</span> fs = <span class="hljs-built_in">require</span>(‘fs’);
<span class="hljs-keyword">var</span> contents = fs.readFileSync(<span class="hljs-string">'package.json'</span>).toString();
<span class="hljs-built_in">console</span>.log(contents);

In** Non-blocking I/O **operations, you can get the user2 data without waiting for the completion of the user1 request. You can initiate both requests in parallel. **Non-blocking I/O **eliminates the need for the multi-threaded, since the system can handle multiple requests at the same time. That is the main reason which makes it very fast.

Example of Non-blocking I/O operation

<span class="hljs-keyword">const</span> fs = <span class="hljs-built_in">require</span>(‘fs’);
fs.readFile(<span class="hljs-string">'package.json'</span>, <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">err, buf</span>)</span>{
    <span class="hljs-built_in">console</span>.log(buf.toString());
});

Note: You can learn more about the event loop and other things by going through this link.

What is Node Package Manager ( NPM )

It is is the official package manager for the node. It bundles automatically installed when you install node in your system. It is used to install new packages and manage them in useful ways. NPM install packages in two modes local and global. In the local mode, NPM installs packages in the node_module directory of the current working directory which location is owned by current user. Global packages installed in the directory where the node is installed and the location is owned by the root user.

What is the package.json

package.json is a plain JSON text file which manages all the packaged which you installed in your node application. Every Node.js applications should have this file at the root directory to describe the application metadata. A simple package.json file looks like below

{
    <span class="hljs-string">"name"</span> : <span class="hljs-string">"codesquery"</span>,
    <span class="hljs-string">"version"</span> : <span class="hljs-string">"1.0.0"'
    "repository": {
	"type" : "git",
	"url" : "github_repository_url"
    },
    "dependencies": {
	"async": "0.8.0",
	"express": "4.2.x"
    }
}
</span>

In the above file, name and versions are mandatory for the package.json file and rest is optional.

Installing Node.js

  • In Windows, you can install the node.js by using the installer provided by the official node.js website. Follow the installer instruction and node.js will be installed in your windows system.
  • In Linux OS, you can install the node.js by adding the PPA in your system and then install node js. Run the below command the terminal to install node js
sudo apt-get install curl python-software-properties
curl -sL https:<span class="hljs-comment">//deb.nodesource.com/setup_10.x | sudo -E bash -</span>
sudo apt-get install nodejs

  • In macOS, download the macOS installer from the official node.js website. Now run the installer by accepting the license and selecting the destination.

Test Node.js Installation

You can test the node.js installation by typing below command in the terminal

node -v

If node.js was installed successfully then you will see the installed version of the node in the terminal.

Frameworks and Tools

After gaining the popularity among the developers, there are so many frameworks built for the node js for the different type of uses. Here, I will tell you some of the most famous node js frameworks in the market

  • Express.js is the most popular framework for node.js development. A lot of popular websites is powered by express.js due to its lightweight.
  • Hapi.js is a powerful and robust framework for developing the API. This framework has features like input validation, configuration based functionality, error handling, caching and logging.
  • Metor.js is one of the most used frameworks in the node js web application development. This framework is backed by a huge community of developers, tutorials and good documentation.
  • Socket.io is used to build a real-time web application like chat system and analytics. Its allow the bi-direction data flow between the web client and server.
  • Koa.js is yet another most used framework to build the web application using the node js. This framework is backed by the team behind Express.js. It allows you to ditch callbacks and increase error handling.

Conclusion

Today, Node.js shaping the future of web and application development technology. This is the just the basic of how node js works. If you want to build a scalable web application using the node js then you need to know more then this.

Till now, you have got the basic idea of node.js and now it is time to build something using the node.js. You can start with first by create a simple server using the node.js and then connect your node with MongoDB to perform the basic crud operation.