Master Django’s MTV Architecture: Views, URLs, Templates, Models & Caching

Django is a Python web framework that follows the MVC pattern, called MTV (Model‑Template‑View) in Django. The model handles data persistence, the template renders HTML, and the view contains business logic linking models and templates.

Views and URL Routing

In Django, views are defined in a views.py module; each view function receives a request object and returns a response, often rendering a template. URL patterns are declared in urls.py using regular expressions, allowing flexible routing.

def home(request):
    values = request.META.items()
    values.sort()
    return render_to_response('home.html', {"values": values})

urlpatterns = patterns('', ('^$', home),)

Templates

Templates are HTML files that display data. Django template tags are written inside {% %} blocks, while variables are output with {{ }}. A base template can define blocks with {% block name %}{% endblock %} and child templates extend it using {% extends "base.html" %}.

Models

Models are defined in models.py and map to database tables. Fields such as CharField, URLField, and relationship fields ( ForeignKey, ManyToManyField) describe the data schema. The Meta class can set default ordering.

class Publisher(models.Model):
    name = models.CharField(max_length=30)
    website = models.URLField()

    def __unicode__(self):
        return self.name

    class Meta:
        ordering = ['name']

class Book(models.Model):
    title = models.CharField(max_length=100)
    authors = models.ManyToManyField(Author)
    publisher = models.ForeignKey(Publisher)
    publication_date = models.DateField(blank=True, null=True)

Admin Integration

Django’s django.contrib.admin provides a powerful admin interface. Register models with admin.site.register and customize the display using a ModelAdmin subclass.

class BookAdmin(admin.ModelAdmin):
    list_display = ('title', 'publisher', 'publication_date')
    list_filter = ('publication_date',)
    date_hierarchy = 'publication_date'
    ordering = ('-publication_date',)
    filter_horizontal = ('authors',)
    raw_id_fields = ('publisher',)

admin.site.register(Publisher)
admin.site.register(Author, AuthorAdmin)
admin.site.register(Book, BookAdmin)

Caching

Django supports three main caching strategies: site‑wide cache, per‑view cache, and per‑data cache, configurable via settings or third‑party backends such as Memcached.