API-middleware-dbConnector-POC

A frontend/backend website using API/middleware/dbConnector pattern implementation for a simple library system (Python, Mysql, JS, HTML, CSS)

Features implemented/used:

• .env file for managing passwords, virtualenv and requirements.txt for managing packages
• db_connector.py: defines a Class for interacting with mysql database
• middleware.py: defines a Class for instantiating a DbConnector, implementing business logic, preparing parameters for contextualized queries for the application and calling its db_connector to execute the queries
• api.py: defines uses Flask to define an API that instantiates Midleware, populates the db if the table books does not exists, exposes a port and defines specific routes according to business logic to be called from frontend, executing Middlewares functions when necessary and handeling/responsing JSONs.
• front.html: defines the structure of the visual browser page used by user. Links front.js and style.css.
• style.css: defines the styling (colours, identation, spacing, shadows) of the application
• front.js: request data to the port served by api.py. Waits for the response in JSON format and mounts the page contents using HTMLElements (Dom manipulation). Each button is binded with a function that calls the api and trigger deleting the content of the page and mounting it again, according the business logic.

Project Requirements

• Python 3
• virtualenv
• mysql

How to run: Setting up backend

0. Create a virtual environment and install python dependencies If you are using a unix-like system, commands are:

virtualnv -p $(which python3) myenv
source myenv
pip install -r requirements.txt

You will see a (myenv) befofe your bash commands now. You can leave the enviroment later using

deactivate

1. Create a Login, Password and Database in Mysql if you don't have one yet
2. Store the login, password and database credentials in a .env file create a .env file. Save your credentials in the following format:

export DATABASE_USER="youruser"
export DATABASE_PASSWORD="yourpassword"
export DATABASE_NAME="yourdatabasename"

3. Save the credentials on your eviroment variables If you are on unix-like system, the command is:

source .env

to unset a variable later, you can use

unset variable

4. Start the server run:

python3 api.py

The backend will start to run on a port (probably 5000). That number is important, it's the number frontend wil request to.

How to run: Setting up frontend

0. Check if front.js port is the same as api.py is running
1. open front.html in a browser
2. Have fun :)