Django Web Framework[Part-2]
Let’s discuss about projects and app structure we want to focus in Django framework. Also we will learn how to create a Django project from scratch. Let get some coffee☕️ and learn 🍀!
The purpose of the project structure is to lay out the files in a way that makes them easy to update.
Django has its own stateless Development server.
Django project structure
In Django, there is a project and under that reusable functionalities are apps. Here news feed, comments, friends , User page are Apps.
Django applications use a combination of below items.
Project Structure
When installing Django globally or in a virtual environment, Python recommends using isolated environment libraries and other dependencies required for a particular application.
Python’s standard library contains the venv module.
It installs a command-line utility called Django-admin in the system path and is located in the scripts folder of your current Python environment.
As the name suggests, you use the django-admin utility to perform various administrative tasks.
These tasks include creating the project and app, performing migrations to generate database tables, whose structure matches data models, and running a development server.
How to create a Django project?
When you set out to build a modular, extensible and scalable web application, you need an arrangement that controls the standard features of its various sub-modules.
A Django project is a Python package containing the database configuration used by various sub-modules (Django calls them apps) and other Django-specific settings.
Steps to start a Django Project.
#create a virtual environment named django-tutorial-env
python3 -m venv django-tutorial-env
#activate virtual environment named django-tutorial-env
source django-tutorial-env/bin/activate
#Install django under django-tutorial-env
(django-tutorial-env) dbasu@Debapriyas-MBP BackendDevelopment % pip3 install django
#Check installed Django version
(django-tutorial-env) dbasu@Debapriyas-MBP BackendDevelopment % python3 -m django version
#Create Django project
(django-tutorial-env) dbasu@Debapriyas-MBP BackendDevelopment % django-admin startproject chefsTable Below folder structure create on your workspace using this commands:
Created manage.py works as django utility command.
To launch development server we can use now manage.py runserver command.
python3 manage.py runserver
Project structure and Files created by Django-admin
The project contains a script manage.py and another folder of the same name.
The manage.py script inside the project has the same role as the django-admin utility.
You can use it to perform various administrative tasks. In that sense, it is a local copy of the django-admin utility.
manage.py
As mentioned above, the manage.py script can perform everything that the django-admin utility does. However, using manage.py is more straightforward, especially if you are required to work on a single project.
If you have multiple projects, use django-admin and specify the settings.
The general usage of manage.py is as follows:
python manage.py <command>
startapp
As mentioned above, a Django project folder can contain one or more apps. An app is also represented by a folder of a specific file system. The command to create an app is:
python manage.py startapp <name of app>
makemigrations
Django manages the database operations with the ORM technique. Migration refers to generating a database table whose structure matches the data model declared in the app.
The following command should be run whenever a new model is declared.
python3 manage.py makemigrationsmigrate
This command option of manage.py synchronizes the database state with the currently declared models and migrations.
python3 manage.py migraterunserver
This command starts Django’s built-in development server on the local machine with IP address 127.0.0.1 and port 8000.
python3 manage.py runserverIt helps if you don’t use this development server in the production environment.
Shell
This command opens up an interactive Python shell inside the project. This is useful when you are required to perform some quick interactive operations.
python3 manage.py shellDjango prefers IPython if it is installed over the standard Python shell.
Project package
The startproject command option of the Django-admin utility creates the folder of the given name, inside which there is another folder of the same name. For example, the command:
django-admin startproject demoproject
This creates a demoproject folder, inside which there’s another demoproject folder.
The inner folder is a Python package. For a folder to be recognized by Python as a package, it must have a file __init__.py.
In addition, the startproject template places four more files in the package folder.
settings.py
Django configures specific parameters with their default values and puts them in this file.
The django-admin utility and manage.py script use these settings while performing various administrative tasks.
urls.py
This script contains a list of object urlpatterns. Every time the client browser requests a URL, the Django server looks to match its pattern and routes the application to the mapped view.
The default structure of urls.py contains a view mapped to the project’s Admin site.
asgi.py
This file is used by the application servers following the ASGI standard to serve asynchronous web applications.
wsgi.py
Many web application servers implement the WSGI standard. This script is the entry point for such WSGI-compatible servers to serve your classical web application.
settings.py
This file defines the attributes that influence the function of a Django application. The startproject template assigns some default values to these attributes. They may be modified as per requirement during the use of the application.
Let us explain some critical settings.
INSTALLED_APPS
This is a list of strings. Each string represents the path of an app inside the parent project folder. The startproject template installs some apps by default. They appear in the INSTALLED_APPS list.
INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
]This list must be updated by adding its name whenever a new app is installed.
For example, if we create a demoapp with the following command:
python3 chefsTable/manage.py startapp testDemoAPPThen, add the ‘testDemoAPP’ string inside the INSTALLED_APP list.
Databases
This attribute is a dictionary that specifies the configuration of one or more databases to be used by the current Django application. By default, Django uses the SQLite database. Hence, this setting has a pre-defined configuration for it.
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': BASE_DIR / 'db.sqlite3',
}
} In place of SQLite, you may choose to use any other. For example, for MySQL, the database settings could be as follows:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'djangotest',
'USER': 'root',
'PASSWORD': 'password',
'HOST': '127.0.0.1',
'PORT': '3306',
}
} Note here the default port number for MySQL is 3306 as against the default port number 8000 used with SQLite in Django.
DEBUG = True
By default, the development server runs in debug mode. This helps develop the application as the server picks up changes in the code and the output can be refreshed without restarting. However, it must be disabled in the production environment.
ALLOWED HOSTS
This attribute is a list of strings. By default, it is empty. Each string represents the fully qualified host/domain where this Django site can be served. For example, to make the site running on localhost externally visible, you may add 0.0.0.0:8000 to this list.
ROOT_URLCONF
This setting is a string pointing toward the urls.py module in which the project’s URL patterns are found. In this case, it would be:
ROOT_URLCONF = ‘chefsTable.urls’
STATIC_URL
This setting points to the folder where the static files, such as JavaScript code, CSS files and images, are placed. Usually, it is set to ‘static/’ corresponding to the folder of this name in the parent project folder.
What’s Next
Previous topics ⭐️👇
Next topics ⭐️👇
I will sum up few more topics which I found interesting to look at. Let’s get learning🍀!
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