Project: Item Catalog

The second project in the Fullstack Web Developer Nanodegree.

Runtime Dependencies

Python 2.7 - the application runtime.
Flask - the web application framework.
sqlalchemy - the ORM library for the underlying database.
requests-oauthlib - for handling OAuth2 flows.
flask-login - for handling session management and protecting views.
psycopg2 - the PostgreSQL DB API for Python.

Dev Dependencies

pycodestyle - for checking code style practices.
autopep8 - for automatically fixing issues reported by pycodestyle.

Server Configuration

The application is designed to be deployed using nginx as a reverse proxy to a gunicorn wsgi application server enabled via systemd.

Software Installed

Python 2.7 and pip
Nginx (web server / reverse proxy)
Gunicorn (wsgi application server)
PostgreSQL (database backend)
Certbot + LetsEncrypt

Configuration Summary

The ssh service is configured to only permit publickey authentication for all users. The service is bound to port 2200 instead of 22 and the root user is not permitted to log in remotely.
PostgreSQL is installed and configured to accept connections from localhost only. Peer authentication is used for the catalog user.
- Because peer authentication is used for connecting to the database, the corresponding system user (catalog) is not permitted to log into the server at all. Any attempts will result in a "This account is currently not available" message.
Gunicorn is the wsgi server used to serve the application. It only listens to requests from localhost:8080. It runs the application as the catalog system user.
- Gunicorn is configured as a systemd service. This enables startup on boot of the server, and status checks/stops/starts can be handled through typical systemctl/service commands. Logs are sent to journal automatically by systemd.
Nginx is configured as the primary web server and reverse proxy.
- Nginx also routes all HTTP requests (on port 80) to HTTPS (443) to ensure encrypted communication for the user, since requests-oauthlib requires it.
TLS/SSL certificates were obtained using LetsEncrypt and Certbot.

Running the App Locally

Ensure the fullstack-nanodegree-vm project has been downloaded.
Ensure VirtualBox and Vagrant have been installed.
Clone or download this repository and copy the file contents to the vagrant/catalog/ directory in the fullstack-nanodegree-vm project mentioned in step 1.

Bring up the vagrant machine and ssh into it.

 $ cd fullstack-nanodegree-vm/vagrant
 $ vagrant up
 $ vagrant ssh

Ensure all of the project dependencies are installed.

$ cd /vagrant/catalog/
$ sudo pip install -r requirements.txt

Create a file called client_secrets.json and paste the provided text into it. This file is required for GitHub (the OAuth2 provider) to verify this application.

Do the database setup and run the application

# setup the database
$ python dbhelper.py

# run the flask app
$ python application.py

To stop the application, go back to your vagrant session and hit control + c.

Interacting With the Application

If you are using the deployed version of the application, please substitute the references to localhost:8000 with https://tlkamp.com.

Navigate to http://localhost:8000/ in a browser. To interact with the json endpoints, please use the following:

http://localhost:8000/catalog/json for a full catalog listing
http://localhost:8000/catalog/json/item/<item id number> for informaiton about a specific database item.

An item that does not exist

$ curl -i http://localhost:8000/catalog/json/item/3
HTTP/1.0 404 NOT FOUND
Content-Type: application/json
Content-Length: 29
Server: Werkzeug/0.14.1 Python/3.6.5
Date: Mon, 21 Jan 2019 01:05:02 GMT

{
  "message": "Not found"
}

An individual item

$ curl -i http://localhost:8000/catalog/json/item/2
HTTP/1.0 200 OK
Content-Type: application/json
Content-Length: 209
Server: Werkzeug/0.14.1 Python/3.6.5
Date: Mon, 21 Jan 2019 01:05:00 GMT

{
  "item": {
    "category": "Default",
    "description": "something with a later modified date",
    "id": 2,
    "last_updated": "2019-01-20 13:31",
    "name": "another default",
    "user": 1
  }
}

The full catalog listing

$ curl -i http://localhost:8000/catalog/json/
HTTP/1.0 200 OK
Content-Type: application/json
Content-Length: 580
Server: Werkzeug/0.14.1 Python/3.6.5
Date: Mon, 21 Jan 2019 01:05:06 GMT

{
  "categories": [
    {
      "id": 1,
      "items": [
        {
          "category": "Default",
          "description": "something to test with",
          "id": 1,
          "last_updated": "2019-01-20 13:31",
          "name": "default item",
          "user": 1
        },
        {
          "category": "Default",
          "description": "something with a later modified date",
          "id": 2,
          "last_updated": "2019-01-20 13:31",
          "name": "another default",
          "user": 1
        }
      ],
      "name": "Default"
    }
  ]
}

tlkamp/project-item-catalog