mesbot
Facebook Messenger Bot Framework
Last updated 2 years ago by andrijdavid .
MIT · Repository · Bugs · Original npm · Tarball · package.json
$ cnpm install mesbot 
SYNC missed versions from official npm registry.

MBot is a simple but powerful JavaScript Framework to build Facebook Messenger's Chat bots.

Features Usage Getting Started Documentation Examples Credits License

Features

  • Helper methods to send any type of message supported by Facebook.
  • Subscribe to a particular type of message, or to certain keywords sent by the user.
  • Start conversations, ask questions and save important information in the context of the conversation.
  • Organize your code in modules.
  • Send automatic or manual typing indicators.
  • Set threads such as a persistent menu, a greeting text or a get started CTA.
  • Subscribe to received and read events.

Usage

$ npm install mesbot --save
'use strict';
const MBot = require('mesbot');

const bot = new MBot({
  accessToken: 'FB_ACCESS_TOKEN',
  verifyToken: 'FB_VERIFY_TOKEN',
  appSecret: 'FB_APP_SECRET'
});

bot.on('message', (payload, chat) => {
  const text = payload.message.text;
  chat.say(`Echo: ${text}`);
});

bot.start();

Getting Started

  • Install MBot via NPM, create a new index.js, require MBot and create a new bot instance using your Facebook Page's / App's accessToken, verifyToken and appSecret:
// index.js
'use strict';
const MBot = require('mesbot');

const bot = new MBot({
  accessToken: 'FB_ACCESS_TOKEN',
  verifyToken: 'FB_VERIFY_TOKEN',
  appSecret: 'FB_APP_SECRET'
});
  • Subscribe to messages sent by the user with the bot.on() and bot.hear() methods:
bot.on('message', (payload, chat) => {
	const text = payload.message.text;
	console.log(`The user said: ${text}`);
});

bot.hear(['hello', 'hi', /hey( there)?/i], (payload, chat) => {
	console.log('The user said "hello", "hi", "hey", or "hey there"');
});
  • Reply to user messages using the chat object:
bot.hear(['hello', 'hi', /hey( there)?/i], (payload, chat) => {
	// Send a text message followed by another text message that contains a typing indicator
	chat.say('Hello, human friend!').then(() => {
		chat.say('How are you today?', { typing: true });
	});
});

bot.hear(['food', 'hungry'], (payload, chat) => {
	// Send a text message with quick replies
	chat.say({
		text: 'What do you want to eat today?',
		quickReplies: ['Mexican', 'Italian', 'American', 'Argentine']
	});
});

bot.hear(['help'], (payload, chat) => {
	// Send a text message with buttons
	chat.say({
		text: 'What do you need help with?',
		buttons: [
			{ type: 'postback', title: 'Settings', payload: 'HELP_SETTINGS' },
			{ type: 'postback', title: 'FAQ', payload: 'HELP_FAQ' },
			{ type: 'postback', title: 'Talk to a human', payload: 'HELP_HUMAN' }
		]
	});
});

bot.hear('image', (payload, chat) => {
	// Send an attachment
	chat.say({
		attachment: 'image',
		url: 'http://example.com/image.png'
	});
});
  • Start a conversation and keep the user's answers in context:
bot.hear('ask me something', (payload, chat) => {
	chat.conversation((convo) => {
		askName(convo);
	});
	
	const askName = (convo) => {
		convo.ask(`What's your name?`, (payload, convo) => {
			const text = payload.message.text;
			convo.set('name', text);
			convo.say(`Oh, your name is ${text}`).then(() => askFavoriteFood(convo));
		});
	};
	
	const askFavoriteFood = (convo) => {
		convo.ask(`What's your favorite food?`, (payload, convo) => {
			const text = payload.message.text;
			convo.set('food', text);
			convo.say(`Got it, your favorite food is ${text}`).then(() => sendSummary(convo));
		});
	};
	
	const sendSummary = (convo) => {
		convo.say(`Ok, here's what you told me about you:
	      - Name: ${convo.get('name')}
	      - Favorite Food: ${convo.get('food')}`);
      convo.end();
	};
});
  • Set up webhooks and start the express server:
bot.start();
  • Start up your bot by running node:
$ node index.js
> MBot running on port 3000
> Facebook Webhook running on localhost:3000/webhook

Then use the provided HTTPS URL to config your webhook on Facebook's Dashboard.

Documentation

MBot Class

new MBot(options)

options key Type Default Required
accessToken string Y
verifyToken string Y
appSecret string Y
broadcastEchoes boolean false N
name string Y

Creates a new MBot instance. Instantiates the new express app and all required webhooks. options param must contain all tokens and app secret of your Facebook app. Optionally, set broadcastEchoes to true if you want the messages your bot send to be echoed back to it (you probably don't need this feature unless you have multiple bots running on the same Facebook page).

.start([ port ])

Param Type Default Required
port number 3000 N

Starts the express server on the specified port. Defaults port to 3000.

.close()

Closes the express server (calls .close() on the server instance).


Receive API

Use these methods to subscribe your bot to messages, attachments or anything the user might send.

.on(event, callback)

Param Type Default Required
event string Y
callback function Y

Subscribe to an event emitted by the bot, and execute a callback when those events are emitted. Available events are:

Event Description
message The bot received a text message from the user
quick_reply The bot received a quick reply from the user (quick replies emit both message and quick_reply events)
attachment The bot received an attachment from the user
postback The bot received a postback call from the user (usually means the user clicked a button)
delivery The bot received a confirmation that your message was delivered to the user
read The bot received a confirmation that your message was read by the user
authentication A user has started a conversation with the bot using a "Send to Messenger" button

You can also subscribe to specific postbacks and quick replies by using a namespace. For example postback:ADD_TO_CART subscribes only to the postback event containing the ADD_TO_CART payload.

If you want to subscribe to specific keywords on a message event, see the .hear() method below.

When these events ocurr, the specified callback will be invoked with 3 params: (payload, chat, data)

Param Description
payload The data sent by the user (contains the text of the message, the attachment, etc.)
chat A Chat instance that you can use to reply to the user. Contains all the methods defined in the Send API
data Contains extra data provided by the framework, like a captured flag that signals if this message was already captured by a different callback
.on() examples:
bot.on('message', (payload, chat) => {
	console.log('A text message was received!');
});

bot.on('attachment', (payload, chat) => {
	console.log('An attachment was received!');
});

bot.on('postback:HELP_ME', (payload, chat) => {
	console.log('The Help Me button was clicked!');
});

bot.on('message', (payload, chat) => {
	// Reply to the user
	chat.say('Hey, user. I got your message!');
});

.hear(keywords, callback)

Param Type Default Required
keywords string, regex or mixed array Y
callback function Y

A convenient method to subscribe to message events containing specific keywords. The keyword param can be a string, a regex or an array of both strings and regexs that will be tested against the received message. If the bot receives a message that matches any of the keywords, it will execute the specified callback. String keywords are case-insensitive, but regular expressions are not case-insensitive by default, if you want them to be, specify the i flag.

The callback's signature is identical to that of the .on() method above.

.hear() examples:
bot.hear('hello', (payload, chat) => {
	chat.say('Hello, human!');
});

bot.hear(['hello', 'hi', 'hey'], (payload, chat) => {
	chat.say('Hello, human!');
});

bot.hear([/(good)?bye/i, /see (ya|you)/i, 'adios'], (payload, chat) => {
	// Matches: goodbye, bye, see ya, see you, adios
	chat.say('Bye, human!');
});

Note that if a bot is subscribed to both the message event using the .on() method and a specific keyword using the .hear() method, the event will be emitted to both of those subscriptions. If you want to know if a message event was already captured by a different subscription, you can check for the data.captured flag on the callback.


Send API

MBot provides helper methods for every type of message supported by Facebook's Messenger API. It also provides a generic sendMessage method that you can use to send a custom payload. All messages from the Send API return a Promise that you can use to apply actions after a message was successfully sent. You can use this to send consecutive messages and ensure that they're sent in the right order.

Important Note:

The Send API methods are shared between the MBot, Chat and Conversation instances, the only difference is that when you use any of these methods from the Chat or Conversation instances, you don't have to specify the userId.

Example - These two methods are identical:

bot.on('message', (payload, chat) => {
  const text = payload.message.text;
  const userId = payload.sender.id;
  bot.say(userId, 'Hello World');
});

// is the same as...

bot.on('message', (payload, chat) => {
  const text = payload.message.text;
  chat.say('Hello World');
});

You'll likely use the Send API methods from the Chat or Conversation instances (ex: chat.say() or convo.say()), but you can use them from the MBot instance if you're not in a chat or conversation context (for example, when you want to send a notification to a user).

.say()

Method signature
chat.say(message, [ options ])
convo.say(message, [ options ])
bot.say(userId, message, [ options ])

Send a message to the user. The .say() method can be used to send text messages, button messages, messages with quick replies or attachments. If you want to send a different type of message (like a generic template), see the Send API method for that specific type of message.

The message param can be a string or an object:

  • If message is a string, the bot will send a text message.
  • If message is an object, the message type will depend on the object's format:
// Send a text message
chat.say('Hello world!');

// Send a text message with quick replies
chat.say({
	text: 'Favorite color?',
	quickReplies: ['Red', 'Blue', 'Green']
});

// Send a button template
chat.say({
	text: 'Favorite color?',
	buttons: [
		{ type: 'postback', title: 'Red', payload: 'FAVORITE_RED' },
		{ type: 'postback', title: 'Blue', payload: 'FAVORITE_BLUE' },
		{ type: 'postback', title: 'Green', payload: 'FAVORITE_GREEN' }
	]
});

// Send an attachment
chat.say({
	attachment: 'video',
	url: 'http://example.com/video.mp4'
});

// or
chat.sendVideoMessage(url);
chat.sendAudioMessage(url);
chat.sendImageMessage(url);

The options param can contain:

options key Type Default Description
typing boolean or number false Send a typing indicator before sending the message. If set to true, it will automatically calculate how long it lasts based on the message length. If it's a number, it will show the typing indicator for that amount of milliseconds (max. 20000 - 20 seconds)
onDelivery function Callback that will be executed when the message is received by the user. Receives params: (payload, chat, data)
onRead function Callback that will be executed when the message is read by the user. Receives params: (payload, chat, data)

.sendTextMessage()

Method signature
chat.sendTextMessage(text, [ quickReplies, options ])
convo.sendTextMessage(text, [ quickReplies, options ])
bot.sendTextMessage(userId, text, [ quickReplies, options ])

The text param must be a string containing the message to be sent.

The quickReplies param can be an array of strings or quick_reply objects.

The options param is identical to the options param of the .say() method.

.sendButtonTemplate()

Method signature
chat.sendButtonTemplate(text, buttons, [ options ])
convo.sendButtonTemplate(text, buttons, [ options ])
bot.sendButtonTemplate(userId, text, buttons, [ options ])

The text param must be a string containing the message to be sent.

The buttons param can be an array of strings or button objects.

The options param is identical to the options param of the .say() method.

.sendGenericTemplate()

Method signature
chat.sendGenericTemplate(elements, [ options ])
convo.sendGenericTemplate(elements, [ options ])
bot.sendGenericTemplate(userId, elements, [ options ])

The elements param must be an array of element objects.

The options param is identical to the options param of the .say() method.

.sendTemplate()

Method signature
chat.sendTemplate(payload, [ options ])
convo.sendTemplate(payload, [ options ])
bot.sendTemplate(userId, payload, [ options ])

Use this method if you want to send a custom template payload, like a receipt template or an airline itinerary template.

The options param is identical to the options param of the .say() method.

.sendAttachment()

Method signature
chat.sendAttachment(type, url, [ quickReplies, options ])
convo.sendAttachment(type, url, [ quickReplies, options ])
bot.sendAttachment(userId, type, url, [ quickReplies, options ])

The type param must be 'image', 'audio', 'video' or 'file'.

The url param must be a string with the URL of the attachment.

The quickReplies param can be an array of strings or quick_reply objects.

The options param is identical to the options param of the .say() method.

.sendAction()

Method signature
chat.sendAction(action, [ options ])
convo.sendAction(action, [ options ])
bot.sendAction(userId, action, [ options ])

The action param must be 'mark_seen', 'typing_on' or 'typing_off'. To send a typing indicator in a more convenient way, see the .sendTypingIndicator method.

The options param is identical to the options param of the .say() method.

.sendMessage()

Method signature
chat.sendMessage(message, [ options ])
convo.sendMessage(message, [ options ])
bot.sendMessage(userId, message, [ options ])

Use this method if you want to send a custom message object.

The options param is identical to the options param of the .say() method.

.sendTypingIndicator()

Method signature
chat.sendTypingIndicator(milliseconds)
convo.sendTypingIndicator(milliseconds)
bot.sendTypingIndicator(userId, milliseconds)

Convinient method to send a typing_on action and then a typing_off action after milliseconds to simulate the bot is actually typing. Max value is 20000 (20 seconds).

You can also use this method via the typing option (see .say() method).

.getUserProfile()

Method signature
chat.getUserProfile()
convo.getUserProfile()
bot.getUserProfile(userId)

This method is not technically part of the "Send" API, but it's listed here because it's also shared between the bot, chat and convo instances.

Returns a Promise that contains the user's profile information.

bot.hear('hello', (payload, chat) => {
  chat.getUserProfile().then((user) => {
    chat.say(`Hello, ${user.first_name}!`);
  });
});

Conversations

Conversations provide a convenient method to ask questions and handle the user's answer. They're useful when you want to set a flow of different questions/answers, like an onboarding process or when taking an order for example. Conversations also provide a method to save the information that you need from the user's answers, so the interaction is always in context.

Messages sent by the user won't trigger a global message, postback, attachment or quick_reply event if there's an active conversation with that user. Answers must be managed by the conversation.

bot.conversation()

Method signature
chat.conversation(factory)
bot.sendButtonTemplate(userId, factory)

Starts a new conversation with the user.

The factory param must be a function that is executed immediately receiving the convo instance as it's only param:

bot.on('hello', (payload, chat) => {
	chat.conversation((convo) => {
		// convo is available here...
		convo.ask( ... );
	});
});

convo.ask(question, answer, [ callbacks, options ])

Param Type Default Required
question string, object or function Y
answer function Y
callbacks array N
options object N

If question is a string or an object, the .say() method will be invoked immediately with that string or object, if it's a function it will also be invoked immedately with the convo instance as its only param.

The answer param must be a function that receives the payload, convo and data params (similar to the callback function of the .on() or .hear() methods, except it receives the convo instance instead of the chat instance). The answer function will be called whenever the user replies to the question with a text message or quick reply.

The callbacks array can be used to listen to specific types of answers to the question. You can listen for postback, quick_reply and attachment events, or you can match a specific text pattern. See example bellow:

The options param is identical to the options param of the .say() method.

convo.ask() example:
const question = {
	text: `What's your favorite color?`,
	quickReplies: ['Red', 'Green', 'Blue']
};

const answer = (payload, convo) => {
	const text = payload.message.text;
	convo.say(`Oh, you like ${text}!`);
};

const callbacks = [
	{
		event: 'quick_reply',
		callback: () => { /* User replied using a quick reply */ }
	},
	{
		event: 'attachment',
		callback: () => { /* User replied with an attachment */ }
	},
	{
		pattern: ['black', 'white'],
		callback: () => { /* User said "black" or "white" */ }
	}
];

const options = {
	typing: true // Send a typing indicator before asking the question
};

convo.ask(question, answer, callback, options);

convo.set(property, value)

Param Type Default Required
property string Y
value mixed Y

Save a value in the conversation's context. This value will be available in all subsequent questions and answers that are part of this conversation, but the values are lost once the conversation ends.

convo.question(`What's your favorite color?`, (payload, convo) => {
	const text = payload.message.text;

	// Save the user's answer in the conversation's context.
	// You can then call convo.get('favoriteColor') in a future question or answer to retrieve the value.
	convo.set('favoriteColor', text);
	convo.say(`Oh, you like ${text}!`);
});

convo.get(property)

Param Type Default Required
property string Y

Retrieve a value from the conversation's context.

convo.end()

Ends a conversation, giving control back to the bot instance. All .on() and .hear() listeners are now back in action. After you end a conversation the values that you saved using the convo.set() method are now lost.

You must call convo.end() after you no longer wish to interpret user's messages as answers to one of your questions. If you don't, and a message is received with no answer callback listening, the conversation will be ended automatically.


Modules

Modules are simple functions that you can use to organize your code in different files and folders.

.module(factory)

The factory param is a function that gets called immediatly and receives the bot instance as its only parameter. For example:

// help-module.js
module.exports = (bot) => {
	bot.hear('help', (payload, chat) => {
		// Send Help Menu to the user...
	});
};

// index.js
const helpModule = require('./help-module');
bot.module(helpModule);

Take a look at the examples/module-example.js file for a complete example.


Threads

.setGreetingText(text)

Facebook Docs

Param Type Default Required
text string Y

Set a greeting text for new conversations. The Greeting Text is only rendered the first time the user interacts with a the Page on Messenger.

.setGetStartedButton(action)

Facebook Docs

Param Type Default Required
action string or function Y

React to a user starting a conversation with the bot by clicking the Get Started button. If action is a string, the Get Started button postback will be set to that string. If it's a function, that callback will be executed when a user clicks the Get Started button.

.deleteGetStartedButton()

Removes the Get Started button call to action.

.setPersistentMenu(buttons)

Facebook Docs

Param Type Default Required
buttons array of strings or objects Y

Creates a Persistent Menu that is available at any time during the conversation. The buttons param can be an array of strings or button objects.

.deletePersistentMenu()

Removes the Persistent Menu.

Examples

Check the examples directory to see more demos of:

  • An echo bot
  • A bot that searches for random gifs
  • An example conversation with questions and answers
  • How to organize your code using modules
  • How to use threads to set a Persistent Menu or a Get Started CTA
  • How to get the user's profile information

To run the examples, make sure to complete the examples/config/default.json file with your bot's tokens, and then cd into the examples folder and run the desired example with node. For example:

$ cd examples
$ node echo-example.js

Credits

Made with :heart: by Andrij David

License

MIT

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