Marsan-Ma-zz / fb_messenger

a verified minimum python flask server framework for facebook messenger backend.

Minimum Facebook ChatBot App

A facebook chatbot (messenger) backend server, written in python flask framework

Deploy Steps

Take a glimpse on facebook official tutorial, then start wondering:

1. How to get some free and workable SSL certificate?
2. What the heck about these tokens?

Free Workable SSL certification!

Facebook don't accept self-signed SSL key, but SSL certificate from trusted source is not free, usually like $50/yr at least.

Thanks to guys from ISRG (Internet Security Research Group), we have free ssl certificate that accepted by main-stream browsers, and most important --- accepted by Facebook!

You could follow the official tutorial from let's encrypt, or inshort, just type:

  wget https://dl.eff.org/certbot-auto
  chmod a+x certbot-auto
  ./certbot-auto certonly --standalone -d <your.domain.name>

Then your keys are available in /etc/letsencrypt/live, yay!
(Note that port 443 (https) should not blocked by firewall, else can't be verified.)

Then you need to copy this two key file into you ssl folder:

cp /etc/letsencrypt/live/fullchain1.pem  fb_messenger/ssl/server.crt
cp /etc/letsencrypt/live/privkey1.pem  fb_messenger/ssl/server.key

Creating Facebook App, and the Tokens

There are two tokens matters here:

• The VERIFY_TOKEN for facebook to verify that YOU OWN THE DOMAIN, this token will only used once. And you will fill-in whatever you like in this step:

And you will fill the same in config.yaml You can't pass the Verify and Save button because once you click it, facebook will try to access your site and make sure:

1. you have SSL certificate ready
2. you have token setup ready

We will come back later and click this darn button later, after we settle everything...

• The FACEBOOK_TOKEN for sending message on behalf of your certain facebook fanpage, which you get it from this step:

Also, you will fill the same in config.yaml

Finally, start your server!

You need to start your server by python3 app.py, and make sure it's public accessible by Facebook to verify your SSL is working!

Now we could go back to the webhook part, click this Verify and Save button and see it done!

Enjoy the chatting with your bot!