A Small Introduction to Django
Installation of django:
pip3 install django
To create a project in Django named ‘Hello’:
Command: django-admin startproject Hello
With the above command we create a project named Hello and some inbuilt code is given to the user so that user can do modifications of his need
To get to know whether the django is working properly
type command : python manage.py runserver inside the project we created
Model View Template Architecture of Django:
Model: It is the information used in database design.
View: runtime we pull the data from model and do some calculation on the data. Gives the processed output to a template
Create an app in django:
There could be a problem in understanding what is a project and what is app? To become a project fully functional there could be at least one or more apps. In simple projects there could be only one app
Command to create an app
python manage.py startapp <App name>
Here consider the app name is HelloWorldApp
URL Dispatching :
Before understanding how the django works, we put a new file called urls.py in app (HelloWorldApp)
whenever we want to access a URL in the project. The controller goes to the urls.py in the project page
“””HelloWorld URL Configuration
The `urlpatterns` list routes URLs to views. For more information please see:
https://docs.djangoproject.com/en/3.2/topics/http/urls/
Examples:
Function views
1. Add an import: from my_app import views
2. Add a URL to urlpatterns: path(‘’, views.home, name=’home’)
Class-based views
1. Add an import: from other_app.views import Home
2. Add a URL to urlpatterns: path(‘’, Home.as_view(), name=’home’)
Including another URLconf
1. Import the include() function: from django.urls import include, path
2. Add a URL to urlpatterns: path(‘blog/’, include(‘blog.urls’))
“
from django.contrib import admin
from django.urls import path,include
urlpatterns = [
path(‘admin/’, admin.site.urls),
path(‘’,include(‘HelloWorldApp.urls’))
]
This is how urls.py page looks like in project page. It tells that if the url is ending with admin go to the admin.site.urls
If nothing is given in the URL then go to the URL page of HelloWorldApp
from django.contrib import admin
from django.urls import path
from HelloWorldApp import views
urlpatterns = [
path(‘’,views.index,name=’Home’)
]
This is how urls.py page looks in the app page.This states that if the url is blank then go to the views.py and call the function index
from django.shortcuts import render,HttpResponse
# Create your views here.
def index(request):
context={
‘variable’: ‘this is sent from views’
}
return render(request,’index.html’,context)
#return HttpResponse(‘This is a home page’)
def about(request):
return render(request,’about.html’)
# return HttpResponse(‘This is a about page’)
def services(request):
return render(request,’services.html’,)
#return HttpResponse(‘This is a services page’)
def contact(request):
return render(request,’contact.html’)
#return HttpResponse(‘This is a contact page’)
This is the views.py page. If a user calls with out any name then index function gets executed.
Generally we do not like to see webpage stating ‘ This is home page’. All want beautiful web pages. So instead of text we use templates and render them
Static files:
Static files are the files that are publicly accessible to the user.
Configuration of static files:
1. Create a folder called static inside the project.
2.Inside the folder create a file (named staticfile.txt). Add the contents you wish to add
3. In your settings file which is present in the Project folder ,
define STATIC_URL, for example:
STATIC_URL = ‘/static/’
3. Add the below code in settings.py
STATICFILES_DIRS=[
os.path.join(BASE_DIR,’static’)
]
Note: Do not put sensitive data in the static files as any user can see the data and become a security loop hole
Templates:
These are normal html files which are used to display nice webpages to the user
Configuration of templates.
1. Create a folder called templates inside the project
1. In settings.py we have
TEMPLATES = [
{
‘BACKEND’: ‘django.template.backends.django.DjangoTemplates’,
‘DIRS’: [os.path.join(BASE_DIR,’templates’)],
‘APP_DIRS’: True,
‘OPTIONS’: {
‘context_processors’: [
‘django.template.context_processors.debug’,
‘django.template.context_processors.request’,
‘django.contrib.auth.context_processors.auth’,
‘django.contrib.messages.context_processors.messages’,
],
},
},
]
In DIRS we place the template folder name.
Inside the template folder add the html files as much as you want. In this example I added only one html file index.html
To see the html page we use app.views page and their instead of return HTTPResponse we use return render(request,’<name of the html page >’)
def index(request):
return render(request,’index.html’)
python manage.py makemigrations — — sees whether there is any database changes ocured with in the the project
Create super user in Django:
Super-user is the administrator of the particular project.
To create superuser
python manage.py createsuperuser
If any error comes likes the below:
sqlite3.OperationalError: no such table: auth_user
The above exception was the direct cause of the following exception:………………….
then do the
python manage.py makemigrations
python manage.py migrate
python manage.py createsuperuser
After successful creation of superuser goto 127.0.0.1:8000/admin and enter the credentials if the createsuperuser is success then login to the administrator
Maintain same theme in all the web pages.
It is important in production that all the webpages have same style that means the style present in Home.html should be same as style in contacts.html
To achieve that we put all the style in the base.html file in the templates folder.
And in each html page like Home.html the first statement would be like
{% extends ‘base.html’ %}
when django sees this line it extends the properties present in the base.html and renders to the Home.html page
Furthermore, we will discuss in the next blog