eClass BackEnd

Introduction:

This is the back-end app for E-Class system.

Tools needed

• Git
• Python3 + pip (or any other package manager)

Setup and preparation (~ 6 hours)

• Create virtual environment e.g.: python -m venv .env

• Activate virtual environment in console e.g.:

  • .env/Scripts/activate.ps1 // Windows
  • source .env/bin/activate // Linux/Mac

• pip3 install django to install django framework,

• pip3 install djangorestframework to install django rest framework

• django-admin startproject dundts_backend to create dundts_backend project,

• cd dundts_backend changes directory to the dundts_backend project,

• django-admin startapp eclass to create eclass api module,

• The tree of the project is as follows:

  ├── db.sqlite3
  ├── dundts_backend
  │   ├── asgi.py
  │   ├── __init__.py
  │   ├── __pycache__
  │   │   ├── __init__.cpython-39.pyc
  │   │   ├── settings.cpython-39.pyc
  │   │   ├── urls.cpython-39.pyc
  │   │   └── wsgi.cpython-39.pyc
  │   ├── settings.py
  │   ├── urls.py
  │   └── wsgi.py
  ├── eclass
  │   ├── admin.py
  │   ├── apps.py
  │   ├── __init__.py
  │   ├── migrations
  │   │   └── __init__.py
  │   ├── models.py
  │   ├── tests.py
  │   └── views.py
  ├── manage.py
  └── README.md

• Adding 'rest_framework', and 'eclass.apps.EclassConfig', to the INSTALLED_APPS section of dundts_backend/settings.py. Each newly installed app should be added to this section.

• python3 manage.py runserver to run the python app.

• pip install pyodbc for creating a connection to the database. I had some problems when installing this package, so after some research, I found these links helpful:

  • For installing package python3-dev: Stackoverflow link 1
  • For Python.h fatal error: Stackoverflow link 2

Creating DAO class and endpoint for getting structural data (~ 4 hours)

To get structural data of e-class tables, a class name EclassDao is created to maintain all methods needed for getting data from e-class tables and creating structural data.

The endpoint is determined in views.py file of eclass module. CORS: To overcome cors error, the following is done:

• pip install django-cors-headers package django-cors-headers is installed,
• adding 'corsheaders', to installed apps in settings.py of project,
• adding 'corsheaders.middleware.CorsMiddleware', to MIDDLEWARE section before common middleware in settings.py of project,
• also adding allowed origins:

  CORS_ALLOWED_ORIGINS = [
      'http://localhost:4200',
  ]

  to settings.py of project,
• More information could be found here.

Adding filters to the endpoint of get structured data (~ 3 hours)

For the purpose of filtering data by table name and table fields, filters are added to the queries.