Installing Python3

• Ubuntu Linux 20.04 LTS includes Python 3.8.5 by default
• Install pip3 (Python Package Index tool)

$ sudo apt install python3-pip

Python virtual environment

(ref: https://developer.mozilla.org/en-US/docs/Learn/Server-side/Django/development_environment#using_django_inside_a_python_virtual_environment)

1. Install tool using pip3:

$ sudo pip3 install virtualenvwrapper

2. Setting enrironment variables

2.1. Directly, using export command

export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
export VIRTUALENVWRAPPER_VIRTUALENV_ARGS=' -p /usr/bin/python3 '
export PROJECT_HOME=$HOME/Devel

source /usr/local/bin/virtualenvwrapper.sh

2.2. Fill in .bashrc file

• Open file '.bashrc'

$ code ~/.bashrc

• Fill lines

WORKON_HOME=$HOME/.virtualenvs
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
VIRTUALENVWRAPPER_VIRTUALENV_ARGS=' -p /usr/bin/python3 '
PROJECT_HOME=$HOME/Devel

# load virtualenvwrapper for python (after custom PATHs)
venvwrap="virtualenvwrapper.sh"
/usr/bin/which -a $venvwrap
if [ $? -eq 0 ]; then
    venvwrap=`/usr/bin/which $venvwrap`
    source $venvwrap
fi

• Load environment

$ source ~/.bashrc

3. Creating virtual environment

$ mkvirtualenv my_django_environment

4. Installing Django

• // Check the latest version: https://www.djangoproject.com/download/

$ pip3 install django~=3.1

4. Using virtual environment: commands

$ deactivate // Exit out of the current Python virtual environment

$ workon // List available virtual environments

$ workon my_django_environment // Activate the specified Python virtual environment

$ rmvirtualenv my_django_environment // Remove the specified environment.

Create skeleton Django project

1. Create a folder contain project

$ mkdir django_project
$ cd django_project

2. Start project:

$ django-admin startproject mysite .

3. Run server

$ python manage.py runserver

4. Go to http://127.0.0.1:8000/

5. Start app

$ python manage.py startapp app_name
// ex: python manage.py startapp stationery

5.1. Registering app: /mysite/settings.py

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    # Add our new application
    'app_name.apps.AppNameConfig', #This object was created for us in /app_name/apps.py
]

5.2. Config database: /mysite/settings.py

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.mysql",
        <!-- "OPTIONS": {
            "read_default_file": "/dj_db_config/mysql/my.cnf",
        }, -->
        "NAME": "db_name",
        "USER": "djangouser",
        "PASSWORD": "password",
        "HOST": "127.0.0.1",
        "PORT": "3306",
    }
}

5.3. Using environment variable

import os


DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.mysql",
        "NAME": os.getenv("DB_NAME"),
        "USER": os.getenv("DB_USERNAME"),
        "PASSWORD": os.getenv("DB_PASSWORD"),
        "HOST": os.getenv("DB_HOST"),
        "PORT": os.getenv("DB_PORT"),
    }
}

6. URL mapper: /mysite/urls.py

from django.contrib import admin
from django.urls import path, include
from django.conf.urls.static import static

urlpatterns = [
    path('admin/', admin.site.urls),
    path('catalog/', include('catalog.urls')),
] + static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)

• /mysite/settings.py

STATIC_ROOT = BASE_DIR.joinpath("static")

7. Running migration

$ python3 manage.py makemigrations
$ python3 manage.py migrate

8. Create supper user

$ python manage.py createsuperuser

9. Manage dependencies: requirements.txt

$ pip3 freeze > requirements.txt

Database setting

(ref: https://www.digitalocean.com/community/tutorials/how-to-create-a-django-app-and-connect-it-to-a-database)

1. Install MySQL database server

$ sudo apt install mysql-server

2. Install MySQL DB connector

$ sudo apt install python3-dev libmysqlclient-dev default-libmysqlclient-dev
$ pip install mysqlclient

3. Create database

3.1. Create user

$ sudo mysql -u root
> CREATE DATABASE db_name;
> SHOW DATABASES;
> CREATE USER 'djangouser'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
> GRANT ALL ON db_name.* TO 'djangouser'@'%';
> FLUSH PRIVILEGES;

3.2. Create file config my.cnf

[client]
database = db_name
user = djangouser
password = 123456
default-character-set = utf8