TaijaQ
4/14/2016 - 11:09 AM

Django Model-View-Controller architecture example

Django Model-View-Controller architecture example

verbatim.py
content_copyfile_download
"""
jQuery templates use constructs like:
    {{if condition}} print something{{/if}}
Or like:
    {% if condition %} print {%=object.something %}{% endif %}
This, of course, completely screws up Django templates,
because Django thinks {{ and }} mean something.
Wrap {% verbatim %} and {% endverbatim %} around those
blocks of jQuery templates and this will try its best
to output the contents with no changes.
"""

from django import template

register = template.Library()


class VerbatimNode(template.Node):

    def __init__(self, text):
        self.text = text

    def render(self, context):
        return self.text


@register.tag
def verbatim(parser, token):
    text = []
    while 1:
        token = parser.tokens.pop(0)
        if token.contents == 'endverbatim':
            break
        if token.token_type == template.TOKEN_VAR:
            text.append('{{ ')
        elif token.token_type == template.TOKEN_BLOCK:
            text.append('{%')
        text.append(token.contents)
        if token.token_type == template.TOKEN_VAR:
            text.append(' }}')
        elif token.token_type == template.TOKEN_BLOCK:
            if not text[-1].startswith('='):
                text[-1:-1] = [' ']
            text.append(' %}')
    return VerbatimNode(''.join(text))
mixins.py
content_copyfile_download
# -*- coding: utf-8 -*-
from django.contrib.auth.decorators import login_required
from django.utils.cache import patch_response_headers
from django.utils.decorators import method_decorator
from django.views.decorators.cache import cache_page, never_cache
from django.views.decorators.csrf import csrf_exempt


class NeverCacheMixin(object):
    @method_decorator(never_cache)
    def dispatch(self, *args, **kwargs):
        return super(NeverCacheMixin, self).dispatch(*args, **kwargs)


class LoginRequiredMixin(object):
    @method_decorator(login_required)
    def dispatch(self, *args, **kwargs):
        return super(LoginRequiredMixin, self).dispatch(*args, **kwargs)


class CSRFExemptMixin(object):
    @method_decorator(csrf_exempt)
    def dispatch(self, *args, **kwargs):
        return super(CSRFExemptMixin, self).dispatch(*args, **kwargs)


class CacheMixin(object):
    cache_timeout = 60

    def get_cache_timeout(self):
        return self.cache_timeout

    def dispatch(self, *args, **kwargs):
        return cache_page(self.get_cache_timeout())(super(CacheMixin, self).dispatch)(*args, **kwargs)


class CacheControlMixin(object):
    cache_timeout = 60

    def get_cache_timeout(self):
        return self.cache_timeout

    def dispatch(self, *args, **kwargs):
        response = super(CacheControlMixin, self).dispatch(*args, **kwargs)
        patch_response_headers(response, self.get_cache_timeout())
        return response


class JitterCacheMixin(CacheControlMixin):
    cache_range = [40, 80]

    def get_cache_range(self):
        return self.cache_range

    def get_cache_timeout(self):
        return random.randint(*self.get_cache_range())
django_mvc.py
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# models.py (the database tables)

from django.db import models

class Book(models.Model):
    name = models.CharField(max_length=50)
    pub_date = models.DateField()


# views.py (the business logic)

from django.shortcuts import render
from models import Book

def latest_books(request):
    book_list = Book.objects.order_by('-pub_date')[:10]
    return render(request, 'latest_books.html', {'book_list': book_list})


# urls.py (the URL configuration)

from django.conf.urls.defaults import *
import views

urlpatterns = patterns('',
    (r'^latest/$', views.latest_books),
)


# latest_books.html (the template)

<html><head><title>Books</title></head>
<body>
<h1>Books</h1>
<ul>
{% for book in book_list %}
<li>{{ book.name }}</li>
{% endfor %}
</ul>
</body></html>