teaching machines

CS 347: Lecture 18 – Today App: Database + Web Service

October 29, 2020 by Chris Johnson. Filed under fall-2020, lectures, webdev.

Dear students:

Last time, we looked at the mechanics of web services using Express. Today we build up a non-toy web service for a time capsule application that lets the user track memories of each day. Behind our web service will be a MySQL database, and our service will have endpoints for the four common CRUD operations for operating on our database’s records: creating, rreading, updating, and deleting.

Here’s your TODO list:

• Install MySQL on your droplet following Digital Ocean’s tutorial. Disable remote logins if prompted. We won’t need remote access to our database.
• Watch The Backend Database.
• Watch Express Meets MySQL.
• Watch CRUD Endpoints.
• Install Nginx with sudo apt install nginx.
• Watch NGINX Meets Express. To get your SSL certificate for your service follow the next steps.
• Add a new DNS record for your service’s subdomain. Log in to Namecheap. Find your domain under Domain List and click Manage. Under Advanced DNS, click Add New Record. Add an A Record. For host, enter your subdomain. Perhaps you want to use today-api like I used in the videos. For the IP address, enter your droplet’s IP address. Save the record.
• Get a new certificate from Let’s Encrypt for your new subdomain with this command: sudo certbot certonly --dry-run --apache -d SUBDOMAIN.YOUR-DOMAIN-NAME. Replace SUBDOMAIN with your subdomain and YOUR-DOMAIN-NAME with your domain name. Once certbot reports success, run the command again but remove --dry-run. We include --dry-run initially because Let’s Encrypt blocks you if you make too many failing requests in an hour, which we are apt to do when figuring all this out. You may have noticed that your service is running through Nginx. Nginx is not Apache, yet we include --apache in the parameters. This is because your Nginx server is not set up to prove to Let’s Encrypt that you own your server, but your Apache server is. In your Nginx host configuration, add these lines:

  ssl_certificate /etc/letsencrypt/live/SUBDOMAIN.YOUR-DOMAIN-NAME/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/SUBDOMAIN.YOUR-DOMAIN-NAME/privkey.pem;

See you next time.

Sincerely,