Laboratório de
Desenvolvimento de Software
FEUP/MIEIC, 2015/16
Ademar Aguiar
Nuno Flores
Rui Maranhão
Hugo Ferreira
Luís Teixeira
url: moodle
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Ruby on Rails
Ruby + MVC = RoR
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Rails em produção
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Projeto Rails
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Plugins, Packages, Tools, etc.
#File ./Gemfile
gem 'rails', '4.0.2'
gem 'sqlite3’
gem 'uglifier', '>= 1.3.0'
gem 'jquery-rails’
gem 'bootstrap-sass-rails', '~> 3.0.3.0’
gem 'debugger’
# Run on console:
# $bundle install
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Routes
MyApp::Application.routes.draw do
root 'welcome#index'
# Example of regular route:
get 'products/:id' => 'catalog#view'
post 'products/:id/purchase' => 'catalog#purchase’
end
§ http://example.com/products/1
§ http://example.com/products/1/purchase
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Controllers
Class CatalogController < ApplicationController
def view
@product = Product.find(params[:id])
# render view.html
end
def purchase
@product = Product.find(params[:id])
@product.purchase()
# render purchase.html
end
end
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Links úteis
§ Gems: http://rubygems.org
§ Docs: http://guides.rubyonrails.org
§ Testing: http://guides.rubyonrails.org/testing.html
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
$rails new ldso_application
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
The Zen of Python
§ Beautiful is better than ugly
§ Explicit is better than implicit
§ Simple is better than complex
§ Complex is better than complicated
§ Readability counts
§…
http://legacy.python.org/dev/peps/pep-0020/
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Dynamic Typing
§ Variable types change with assignment
a = 10
a = “ten”
§ Different from automatic type conversions!
10 + “ objects” in javascript or PHP results in ”10 objects”
§ No method overloading
def my_method(param1, param2):
[…]
return xpto
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Duck Typing
class Duck:
def quack(self):
print("Quaaaaaack!")
class Parrot:
def quack(self):
print("The parrot imitates a duck.")
def make_animal_quack(animal):
animal.quack()
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Multi-paradigm
§ Object-oriented
§ Imperative (procedural)
§ Functional
map(), reduce(), filter(), list comprehensions, …
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
More …
§ Compiles to bytecode
§ Significant whitespace
§ No semicolons
§ No braces
§ The simplest program:
print("Hello world")
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Libraries
§ Standard library
§ Python Package Index (PyPI)
~38000 packages @ Jan 2014
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Command Line Interpreter
$ python
Python 2.4.4 (#1, Oct 18 2006, 10:34:39)
[GCC 4.0.1 (Apple Computer, Inc. build 5341)] on darwin
Type "help", "copyright", "credits" or "license" for more
information.
>>>
>>> a = 'hello'
>>> a
'hello'
>>> a = 1 # Changing a variable type. GC takes care of 'hello’
>>> b = 2
>>> c = a + b
>>> c
3
>>> g
Traceback (most recent call last):
File "", line 1, in ?
NameError: name ‘g' is not defined
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Tools
§ Multi-platform (but better on *nix)
§ Pip
Package Installer
§ Virtualenv
For creating isolated python environments
§ Pycharm or Eclipse + pydev
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Docs
§ The free book “Dive Into Python”
http://www.diveintopython.net/
§ Google's Python Class
https://developers.google.com/edu/python/
§ Python in one easy lesson
http://cs.stanford.edu/people/nick/python-in-one-easy-lesson/
§ Official Docs
http://docs.python.org/
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Framework Features
§ Object-relational mapper
§ Templates
§ URL Routing
§ Internationalization
§ Schema Evolution (now part of Django 1.7!)
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Overview
§ Model-View-Template
•models.py
•views.py
•templates directory…
•urls.py
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Misc
§ Database schema created from models.py
$ python manage.py makemigrations
$ python manage.py migrate
§ Supports schema migration (new in django 1.7)
§ Default database engine: sqlite (postgresql is
better)
§ Internal development server
$ python manage.py runserver
§ Supports pluggable apps
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Projects Vs Apps
§ Supports pluggable apps
•Ex: forum, blog, shopping cart, …
§ Built-in django apps
•admin – “Automatic” Backoffice
•auth – Users and authentication
•formtools – Building forms into webpages
•syndication – Building feeds (rss, atom, …)
•gis – Handling geographic data (GeoDjango)
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Popular Django Apps
§ Celery – task queue (supports RabbitMQ, and Redis)
§ Haystack – full text search
§ Feincms – content management system
§ django-reversion – versioning
§ django-guardian – object-level permissions
§ django-extensions – misc…
§ djangorestframework & django-tastypie – REST
https://www.djangopackages.com/categories/apps/
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Tutorial
djangoproject.com > Documentation > Tutorial >
•Part 1: Object model and “models.py”
•Part 2: Admin module
•Part 3: Public views “urls.py” and “views.py”
•Part 4: Form processing
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Client-side
§ Django + angular.js
§ Django + ember.js
§…
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Famous Websites
§ Disqus
§ Pinterest
§ Instagram
§ bitbucket
§ Lanyrd
§ addons.mozilla.org
§ The Onion
§ washingtonpost.com
§ guardian.co.uk
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
About Scala
§ Object-functional
§ Runs on the JVM
§ Sophisticated static type system
§ Functional features
•Immutability (avoids side-effects)
•Lazy evaluation
•Anonymous functions
•List comprehensions
•Pattern matching
•Tail recursion
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Scala is Reactive!
Today applications are deployed on everything from mobile devices
to cloud-based clusters running thousands of multi-core processors.
Users expect millisecond response times and 100% uptime. Data is
measured in Petabytes. Today's demands are simply not met by
yesterday’s software architectures.
Reactive Systems
Responsive, Resilient, Elastic and Message Driven
http://www.reactivemanifesto.org/
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Benefits
§ Interoperates with Java
§ Supports Traits
§ Concurrency using the Actor Model (Akka)
§ Prepared to scale
•Concurrent and synchronous processing
•Really takes advantage of multiple cores
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Tools
§ IntelliJ or Eclipse
§ SBT
•Dependency management
•Build the system, run the tests, run static analysis, ...
•Many plugins available
http://www.scala-sbt.org/0.13/docs/Community-Plugins.html
§ The Scala shell
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
The Scala Shell
$ scala
This is a Scala shell.
Type in expressions to have them evaluated.
Type :help for more information.
scala> object HelloWorld {
|
def main(args: Array[String]) {
|
println("Hello, world!")
|
}
| }
defined module HelloWorld
scala> HelloWorld.main(null)
Hello, world!
unnamed0: Unit = ()
scala>:q
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Who’s Using It
§ Linkedin
§ Twitter
§ FourSquare
§ Coursera
§ Tumblr
§…
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
About Play
§ Similar/inspired by Ruby on Rails and Django
Supports creating websites with HTML processed on the server-side
§ Written in Scala (initially in Java)
§ JBoss Netty (built-in web server)
§ No ORM, but possible to use Anorm (Scala),
Ebean (Java) or Slick (Scala)
§ Template language is Scala
§ Hot-reloading
§ Part of the typesafe stack: Scala + Akka + Play
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
Resources
§ Official Documentation
http://www.scala-lang.org/documentation/
§ Functional Programming Principles in Scala
https://www.coursera.org/course/progfun
Free, 7 weeks course
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16
[email protected]
FEUP/MIEIC ● Ademar Aguiar ● Laboratório de Desenvolvimento de Software, 2015/16