Django, a popular web framework, provides a built-in regex validator that allows you to enforce specific patterns on input data. Whether you need to validate user input, form fields, or any other data in your Django application, regex validators can be incredibly useful. In this article, we’ll explore how to use regex validators in Django.
Setting up the Project
Installation: To install Django.
Creating the Project
Create the project by using the command:
django-admin startproject bookstore
cd bookstore
Create an application named ‘mini’ by using the command:
python manage.py startapp mini
Now add this app to the ‘INSTALLED_APPS’ in the settings file.
Structuring Your Project
mini/models.py
This code defines a Django model called Vehicle with a registration_number field. The registration_number field is limited to a maximum length of 10 characters and is validated using a RegexValidator to ensure it follows the specified format. The ‘__str__’ method is provided to display the registration number when you print a Vehicle object.
Python3
# models.pyfrom django.core.validators import RegexValidatorfrom django.db import modelsclass Vehicle(models.Model): registration_number = models.CharField( max_length=10, validators=[ RegexValidator( regex=r'^[A-Z]{3}\d{3}$', message="Enter a valid registration number in the format ABC123.", code="invalid_registration", ), ], ) def __str__(self): return self.registration_number |
mini/view.py
These views work together to allow users to add new vehicles with registration numbers following the specified format and to view a list of all vehicles in the system. The ‘add_vehicle’ view handles form submissions, including regex validation, while the vehicle_list view displays the list of vehicles stored in the database.
Python3
# views.pyfrom django.shortcuts import render, redirectfrom .models import Vehiclefrom .forms import VehicleFormdef add_vehicle(request): if request.method == 'POST': form = VehicleForm(request.POST) if form.is_valid(): form.save() return redirect('vehicle_list') else: form = VehicleForm() return render(request, 'add_vehicle.html', {'form': form})def vehicle_list(request): vehicles = Vehicle.objects.all() return render(request, 'vehicle_list.html', {'vehicles': vehicles}) |
mini/form.py
By defining VehicleForm in this manner, you are essentially creating a form that is tightly integrated with the Vehicle model.
Python3
# forms.pyfrom django import formsfrom .models import Vehicleclass VehicleForm(forms.ModelForm): class Meta: model = Vehicle fields = ['registration_number'] |
templates/add_vehicle.html
This file used to add vehicle details.
HTML
<!DOCTYPE html><html><head> <title>Add Vehicle</title></head><body> <h1>Add Vehicle</h1> <form method="post"> {% csrf_token %} {{ form.as_p }} <button type="submit">Save</button> </form></body></html> |
templates/vehicle_list.html
This HTML file is used for listing the vehicles.
HTML
<!DOCTYPE html><html><head> <title>Vehicle List</title></head><body> <h1>Vehicle List</h1> <ul> {% for vehicle in vehicles %} <li>{{ vehicle }}</li> {% empty %} <li>No vehicles in the list.</li> {% endfor %} </ul> <a href="{% url 'add_vehicle' %}">Add Vehicle</a></body></html> |
mini/urls.py
Configure your app’s URLs to map to the views you’ve created:
Python3
# mini/urls.pyfrom django.urls import pathfrom . import viewsurlpatterns = [ path('add-vehicle/', views.add_vehicle, name='add_vehicle'), path('vehicle-list/', views.vehicle_list, name='vehicle_list'),] |
urls.py
Include your app’s URLs in the project’s main urls.py:
Python3
# urls.pyfrom django.contrib import adminfrom django.urls import path, includeurlpatterns = [ path('admin/', admin.site.urls), path('vehicles/', include('your_app.urls')),] |
Output
