Botkit is designed to ease the process of designing and running useful, creative bots that live inside Slack, Facebook Messenger, Twilio IP Messaging, and other messaging platforms.
Botkit features a comprehensive set of tools to deal with Facebooks's Messenger platform, and allows developers to build interactive bots and applications that send and receive messages just like real humans. Facebook bots can be connected to Facebook Pages, and can be triggered using a variety of useful web plugins.
This document covers the Facebook-specific implementation details only. Start here if you want to learn about to develop with Botkit.
Table of Contents
- Getting Started
- Facebook-specific Events
- Working with Facebook Webhooks
- Using Structured Messages and Postbacks
- Thread Settings
- Simulate typing
- Silent and No Notifications
- Running Botkit with an Express server
-
Install Botkit more info here
-
Create a Facebook App for Web and note down or create a new Facebook Page. Your Facebook page will be used for the app's identity.
Copy this token, you'll need it!
-
Define your own "verify token" - this is a string that you control that Facebook will use to verify your web hook endpoint.
-
Run the example bot app, using the two tokens you just created. If you are not running your bot at a public, SSL-enabled internet address, use the --lt option and note the URL it gives you.
page_token=<MY PAGE TOKEN> verify_token=<MY_VERIFY_TOKEN> node facebook_bot.js [--lt [--ltsubdomain CUSTOM_SUBDOMAIN]]
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Set up a webhook endpoint for your app that uses your public URL. Use the verify token you defined in step 4!
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Your bot should be online! Within Facebook, find your page, and click the "Message" button in the header.
Try:
- who are you?
- call me Bob
- shutdown
Since Facebook delivers messages via web hook, your application must be available at a public internet address. Additionally, Facebook requires this address to use SSL. Luckily, you can use LocalTunnel to make a process running locally or in your dev environment available in a Facebook-friendly way.
When you are ready to go live, consider LetsEncrypt.org, a free SSL Certificate Signing Authority which can be used to secure your website very quickly. It is fabulous and we love it.
Facebook sends an X-HUB signature header with requests to your webhook. You can verify the requests are coming from Facebook by enabling validate_requests: true when creating your bot controller. This checks the sha1 signature of the incoming payload against your Facebook App Secret (which is seperate from your webhook's verify_token), preventing unauthorized access to your webhook. You must also pass your app_secret into your environment variables when running your bot.
The Facebook App secret is available on the Overview page of your Facebook App's admin page. Click show to reveal it.
app_secret=abcdefg12345 page_token=123455abcd verify_token=VerIfY-tOkEn node facebook_bot.js
Once connected to Facebook, bots receive a constant stream of events.
Normal messages will be sent to your bot using the message_received event. In addition, several other events may fire, depending on your implementation and the webhooks you subscribed to within your app's Facebook configuration.
| Event | Description |
|---|---|
| message_received | a message was received by the bot |
| facebook_postback | user clicked a button in an attachment and triggered a webhook postback |
| message_delivered | a confirmation from Facebook that a message has been received |
| message_read | a confirmation from Facebook that a message has been read |
| facebook_account_linking | a user has started the account linking |
| facebook_optin | a user has clicked the Send-to-Messenger plugin |
| facebook_referral | a user has clicked on a m.me URL with a referral param |
All incoming events will contain the fields user and channel, both of which represent the Facebook user's ID, and a timestamp field.
message_received events will also contain either a text field or an attachment field.
facebook_postback events will contain a payload field.
Notice also that facebook_postback events trigger the message_received event as well. That is why messages will have the type field as well. When the message is directly from the user (i.e. onlye message_received event) type will be set to "user_message" and when the message is originated in a facebook_postback then type will be set to facebook_postback.
More information about the data found in these fields can be found here.
Botkit receives messages from Facebook using webhooks, and sends messages using Facebook's APIs. This means that your bot application must present a web server that is publicly addressable. Everything you need to get started is already included in Botkit.
To connect your bot to Facebook, follow the instructions here. You will need to collect your page token as well as a verify token that you define yourself and configure inside Facebook's app settings. A step by step guide can be found here. Since you must already be running your Botkit app to configure your Facebook app, there is a bit of back-and-forth. It's ok! You can do it.
Here is the complete code for a basic Facebook bot:
var Botkit = require('botkit');
var controller = Botkit.facebookbot({
access_token: process.env.access_token,
verify_token: process.env.verify_token,
})
var bot = controller.spawn({
});
// if you are already using Express, you can use your own server instance...
// see "Use BotKit with an Express web server"
controller.setupWebserver(process.env.port,function(err,webserver) {
controller.createWebhookEndpoints(controller.webserver, bot, function() {
console.log('This bot is online!!!');
});
});
// this is triggered when a user clicks the send-to-messenger plugin
controller.on('facebook_optin', function(bot, message) {
bot.reply(message, 'Welcome to my app!');
});
// user said hello
controller.hears(['hello'], 'message_received', function(bot, message) {
bot.reply(message, 'Hey there.');
});
controller.hears(['cookies'], 'message_received', function(bot, message) {
bot.startConversation(message, function(err, convo) {
convo.say('Did someone say cookies!?!!');
convo.ask('What is your favorite type of cookie?', function(response, convo) {
convo.say('Golly, I love ' + response.text + ' too!!!');
convo.next();
});
});
});Facebook Messenger supports including "postback" buttons, which, when clicked,
send a specialized facebook_postback event.
As an alternative to binding an event handler to the facebook_postback event,
developers may find it useful if button clicks are treated as "typed" messages.
This enables buttons to be more easily used as part of a conversation flow, and
can reduce the complexity of the code necessary.
Once enabled, the payload field of any postback button that is clicked will be
treated as if the user typed the message, and will trigger any relevant hears triggers.
To enable this option, pass in {receive_via_postback: true} to your Botkit Facebook controller, as below:
var controller = Botkit.facebookbot({
access_token: process.env.access_token,
verify_token: process.env.verify_token,
receive_via_postback: true,
})In order to guarantee the order in which your messages arrive, Botkit supports an optional
delivery confirmation requirement. This will force Botkit to wait for a message_delivered events
for each outgoing message before continuing to the next message in a conversation.
Developers who send many messages in a row, particularly with payloads containing images or attachments, should consider enabling this option. Facebook's API sometimes experiences a delay delivering messages with large files attached, and this delay can cause messages to appear out of order.
To enable this option, pass in {require_delivery: true} to your Botkit Facebook controller, as below:
var controller = Botkit.facebookbot({
access_token: process.env.access_token,
verify_token: process.env.verify_token,
require_delivery: true,
})| Argument | Description |
|---|---|
| port | port for webserver |
| callback | callback function |
Setup an Express webserver for
use with createWebhookEndpoints()
If you need more than a simple webserver to receive webhooks, you should by all means create your own Express webserver! Here is a boilerplate demo.
The callback function receives the Express object as a parameter, which may be used to add further web server routes.
This function configures the route https://_your_server_/facebook/receive
to receive webhooks from Facebook.
This url should be used when configuring Facebook.
You can attach little bubbles
And in those bubbles can be buttons and when a user clicks the button, it sends a postback with the value.
controller.hears('test', 'message_received', function(bot, message) {
var attachment = {
'type':'template',
'payload':{
'template_type':'generic',
'elements':[
{
'title':'Chocolate Cookie',
'image_url':'http://cookies.com/cookie.png',
'subtitle':'A delicious chocolate cookie',
'buttons':[
{
'type':'postback',
'title':'Eat Cookie',
'payload':'chocolate'
}
]
},
]
}
};
bot.reply(message, {
attachment: attachment,
});
});
controller.on('facebook_postback', function(bot, message) {
if (message.payload == 'chocolate') {
bot.reply(message, 'You ate the chocolate cookie!')
}
});Use a message with a sender_action field with "typing_on" to create a typing indicator. The typing indicator lasts 20 seconds, unless you send another message with "typing_off"
var reply_message = {
sender_action: "typing_on"
}
bot.reply(message, reply_message)To make it a bit more realistic, you can trigger a "user is typing" signal (shown in Messenger as a bubble with 3 animated dots) by using the following convenience methods.
bot.startTyping(message, function () {
// do something here, the "is typing" animation is visible
});
bot.stopTyping(message, function () {
// do something here, the "is typing" animation is not visible
});
bot.replyWithTyping(message, 'Hello there, my friend!');When sending a user a message you can make the message have either no notification or have a notification that doesn't play a sound. Both of these features are unique to the mobile application messenger. To do this add the notification_type field to message. Notification type must be one of the following:
- REGULAR will emit a sound/vibration and a phone notification
- SILENT_PUSH will just emit a phone notification
- NO_PUSH will not emit either
notification_type is optional. By default, messages will be REGULAR push notification type
reply_message = {
text: "Message text here",
notification_type: NOTIFICATION_TYPE
}
bot.reply(message, reply_message)Facebook offers a "Thread Settings" API to customize special bot features such as a persistent menu and a welcome screen. We highly recommend you use all of these features, which will make your bot easier for users to work with. Read Facebook's docs here.
| Argument | Description |
|---|---|
| message | greeting message to display on welcome screen |
Remove the greeting message.
| Argument | Description |
|---|---|
| payload | value for the postback payload sent when the button is clicked |
Set the payload value of the 'Get Started' button
Clear the payload value of the 'Get Started' button and remove it.
| Argument | Description |
|---|---|
| menu_items | an array of menu_item objects |
Create a persistent menu for your Bot
Clear the persistent menu setting
controller.api.thread_settings.greeting('Hello! I\'m a Botkit bot!');
controller.api.thread_settings.get_started('sample_get_started_payload');
controller.api.thread_settings.menu([
{
"type":"postback",
"title":"Hello",
"payload":"hello"
},
{
"type":"postback",
"title":"Help",
"payload":"help"
},
{
"type":"web_url",
"title":"Botkit Docs",
"url":"https://github.com/howdyai/botkit/blob/master/readme-facebook.md"
},
]);
controller.api.thread_settings.account_linking('https://www.yourAwesomSite.com/oauth?response_type=code&client_id=1234567890&scope=basic');
controller.api.thread_settings.delete_account_linking();
controller.hears(['hello'],'facebook_postback', function(bot, message) {
//...
});
controller.hears(['help'],'facebook_postback', function(bot, message) {
//...
});Instead of the web server generated with setupWebserver(), it is possible to use a different web server to receive webhooks, as well as serving web pages.
Here is an example of using an Express web server alongside BotKit for Facebook Messenger.