Web Frameworks

By: Rahul Malik

What are they?

• In my opinion - “A software framework that is meant to remove the everyday pain and redundancy of web development.”

Awesome, what are my options??

Ruby on Rails (RoR)• Made at 37 Signals by

DHH

• Paved the way for framework development in many other languages

• Written in Ruby

• Credited with people finding out about ruby

!"#$%&'&$ ())* +,

Django

• Written in Python

• Similar philosophies as Rails except they stress modularity

• Made in Kansas at The World Company

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-$./0#12

345&645#$12

Why do we need them?• Web Programming was a black art

• Bad Practices were formed

• High coupling of components

• Mind numbing processes had to be done repeatedly. (i.e. CRUD pages)

• Infrastructure specific (switching to Oracle = pain)

How do they fix these problems?

Model View Controller Design

Model Controller View

Model

Database Management

• Object Relational Mapping (ORM)

• Switching to another database type is just changing a flag

• Transaction support as well as database migrations

Database Management

class Entry(models.Model): pub_date = models.DateTimeField() slug = models.SlugField(unique_for_date='pub_date') headline = models.CharField(maxlength=200) summary = models.TextField(help_text="Use raw HTML.") body = models.TextField(help_text="Use raw HTML.") author = models.CharField(maxlength=100)

Entry.objects.get(headline=’framework talk’)

Entry.objects.filter(pub_date=datetime.now())

View

Template Systems!

• Simple systems that can be used to generate HTML, CSS, RSS, or any other text based formats

• Controller provides context and separation from model

• Good for designers

Template Systems

{% extends "creator/base.html" %}{% block content %}<h1>User Settings</h1><h2>{{ user.username }}</h2><form action="." method="post">{{ form.as_p }}<input type="submit" value="Save Changes" /></form>{% endblock %}

Controller

Sexy URL’s

• blog.php?month=11&day=19&year=2008

• blog/11/19/2008/

Request Routing

• All HTTP Requests get mapped to a controller or 404 by naming conventions (rails) or regex matching (django)

• domain.com/blog/view/getvar1/getvar2/...

• '^(?P<year>\d{4})/(?P<month>[a-z]{3})/(?P<day>\w{1,2})/(?P<slug>[\w-]+)/$'

Request Routing

• Naming Conventions vs. Regex Matching

• What else to you get?

• GET, POST variables, as much HTTP Header information that you could want

URL Matching (Regex)

from feeds.views import publish_templatized_feed_item, publish_feed_item, refresh_feed

urlpatterns = patterns('', (r'^publish/$', publish_feed_item), (r'^publish/template/$', publish_templatized_feed_item), (r'^refresh/$', refresh_feed))

URL Matching (regex)urlpatterns = patterns('django.views.generic.date_based',

(r'^(?P<year>\d{4})/(?P<month>[a-z]{3})/(?P<day>\w{1,2})/(?P<slug>[\w-]+)/$', 'object_detail', dict(info_dict, slug_field='slug')),

(r'^(?P<year>\d{4})/(?P<month>[a-z]{3})/(?P<day>\w{1,2})/$', 'archive_day', info_dict),

(r'^(?P<year>\d{4})/(?P<month>[a-z]{3})/$', 'archive_month', info_dict),

(r'^(?P<year>\d{4})/$', 'archive_year', info_dict),

(r'^/?$', 'archive_index', info_dict),)

Freebies

Automation

• CRUD or Admin interfaces

• Schema Upgrades and Downgrades (Migrations)

• Generating Frequent Components (new controller, model, etc.)

Security

• Authorization and Authentication of users built-in!

• Permissions Models

• Basic Web Security at it’s core (SQL Injection, CSRF, etc.)

Caching

• Simple hooks and/or helpers baked in

• Flat-File, Database, or Distributed (memcached) database management

But does it scale?

Yes

Any Other Questions?