How Django processes a request (URL → View → Template)

Introduction

Django helps turn a web address into a web page by following clear steps. It finds the right code to run and shows the right page to the user.

When a user types a website address and you want to show them a page.

When you want to organize your website so each URL shows different content.

When you want to separate how you get data (view) from how you show it (template).

When you want to add new pages to your website easily by linking URLs to code.

When you want to reuse page layouts with templates for consistent design.

Syntax

Django

urlpatterns = [
    path('some-url/', views.some_view, name='some_name'),
]

# views.py
from django.shortcuts import render

def some_view(request):
    context = {'key': 'value'}
    return render(request, 'template.html', context)

# template.html
<html>
  <body>
    <p>{{ key }}</p>
  </body>
</html>

URL pattern: Connects a web address to a view function.

View function: Handles the request and sends data to the template.

Examples

This connects the URL '/home/' to the view function home_view.

Django

urlpatterns = [
    path('home/', views.home_view),
]

The view sends the home.html template back to the user.

Django

def home_view(request):
    return render(request, 'home.html')

This template shows a heading using a variable passed from the view.

Django

<h1>Welcome to {{ site_name }}</h1>

Sample Program

This example shows how Django takes the URL '/greet/', runs greet_view, and sends the greet.html template with the name 'Friend'. The page will say "Hello, Friend!".

Django

# urls.py
from django.urls import path
from . import views

urlpatterns = [
    path('greet/', views.greet_view, name='greet'),
]

# views.py
from django.shortcuts import render

def greet_view(request):
    context = {'name': 'Friend'}
    return render(request, 'greet.html', context)

# greet.html
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Greeting</title>
  </head>
  <body>
    <h1>Hello, {{ name }}!</h1>
  </body>
</html>

Important Notes

Django matches URLs in order, so put specific URLs before general ones.

Views can send data to templates using a context dictionary.

Templates use double curly braces {{ }} to show data from views.

Summary

Django turns a URL into a view function using URL patterns.

The view prepares data and chooses a template to show.

The template displays the final page using data from the view.

Practice

1. In Django, what is the first step when a user visits a website URL?

easy

A. Django directly renders the template without processing.

B. Django matches the URL to a view using URL patterns.

C. Django sends data to the database.

D. Django executes JavaScript on the client side.

Solution

1. Step 1: Understand URL routing in Django

   Django uses URL patterns defined in urls.py to find which view should handle the request.

2. Step 2: Identify the first action on a request

   The first action is matching the URL to a view, not rendering or database access.

3. Final Answer:

   Django matches the URL to a view using URL patterns. -> Option B

4. Quick Check:

   URL routing = matching URL to view [OK]

Hint: Remember: URL first matches view, then view handles data [OK]

Common Mistakes:

• Thinking template renders before view runs
• Assuming database is accessed before URL matching
• Confusing client-side JavaScript with Django server process

2. Which of the following is the correct way to define a URL pattern in Django's urls.py?

easy

A. path('home/', views.home_view, name='home')

B. url('home/', views.home_view)

C. route('home/', views.home_view)

D. link('home/', views.home_view)

Solution

1. Step 1: Recall Django URL pattern syntax

   Django 3+ uses path() to define URL patterns, with URL string, view function, and optional name.

2. Step 2: Identify correct function name

   url() is deprecated, and route() or link() are invalid.

3. Final Answer:

   path('home/', views.home_view, name='home') -> Option A

4. Quick Check:

   Use path() for URL patterns [OK]

Hint: Use path() in urls.py, not url() or other names [OK]

Common Mistakes:

• Using deprecated url() instead of path()
• Using non-existent functions like route() or link()
• Omitting the view function argument

3. Given this view function, what will be the rendered output if the template displays {{ message }}?

def hello_view(request):
    context = {'message': 'Hello, Django!'}
    return render(request, 'hello.html', context)

medium

A. Hello, Django!

B. context

C. hello.html

D. request

Solution

1. Step 1: Understand context passing in Django views

   The view passes a dictionary with key 'message' and value 'Hello, Django!' to the template.

2. Step 2: Template renders variable from context

   The template uses {{ message }} to display the value 'Hello, Django!'.

3. Final Answer:

   Hello, Django! -> Option A

4. Quick Check:

   Template variable = context value [OK]

Hint: Template {{ var }} shows context['var'] value [OK]

Common Mistakes:

• Confusing template name with output
• Thinking context dictionary prints as string
• Assuming request object is shown in template

4. What is wrong with this Django view function?

def my_view(request):
    return render('my_template.html')

medium

A. The function name must be capitalized.

B. The template name should be a dictionary.

C. The view should return HttpResponseRedirect instead.

D. The render function is missing the request argument.

Solution

1. Step 1: Check render function signature

   render() requires at least two arguments: request and template name.

2. Step 2: Identify missing argument

   The code only passes the template name, missing the request argument.

3. Final Answer:

   The render function is missing the request argument. -> Option D

4. Quick Check:

   render(request, template) needs request first [OK]

Hint: render() always needs request as first argument [OK]

Common Mistakes:

• Forgetting to pass request to render()
• Thinking template name should be a dict
• Confusing render with redirect functions

5. You want to display a list of products on a page. Which sequence correctly describes how Django processes this request? A user visits /products/. The URL pattern matches products_view. The view fetches products from the database and passes them to products.html template. The template shows the product names in a list. Which is the correct order of steps Django follows internally?

hard

A. View fetches data -> URL matches -> Template renders -> Response sent

B. Template renders -> View fetches data -> URL matches -> Response sent

C. URL -> View fetches data -> Template renders with data -> Response sent

D. Response sent -> URL matches -> View fetches data -> Template renders

Solution

1. Step 1: URL matching

   Django first matches the incoming URL to the correct view function using URL patterns.

2. Step 2: View processes request

   The view fetches data (products) from the database and prepares context for the template.

3. Step 3: Template rendering and response

   The template uses the context to render HTML, which Django sends as the HTTP response.

4. Final Answer:

   URL -> View fetches data -> Template renders with data -> Response sent -> Option C

5. Quick Check:

   URL then view then template then response [OK]

Hint: Remember: URL matches first, then view, then template, then response [OK]

Common Mistakes:

• Thinking template renders before URL matching
• Mixing order of view and URL matching
• Assuming response sent before processing