emaraschio

SOLID Principles with ruby examples

SRP - Single responsibility principle

A class should have only a single responsibility.

Every class should have a single responsibility, and that responsibility should be entirely encapsulated. All its services should be narrowly aligned with that responsibility, this embrace the high cohesion.

OCP - Open/closed principle

Software entities should be open for extension, but closed for modification.

lfbittencourt

#!/usr/bin/env ruby

# Only tags >= min_tag will be removed.
min_tag = '0.0.0'
tags = `git tag`.split(/\s+/).select do |t|
  Gem::Version.new(t) >= Gem::Version.new(min_tag)
end

`git tag -d #{tags.join ' '}`
`git push origin #{tags.map { |t| ':' + t }.join ' '}`

demisx

belongs_to:

1. Assigning an object to a belongs_to association does not automatically save the object. It does not save the associated object either.

has_one:

1. When you assign an object to a has_one association, that object is automatically saved (in order to update its foreign key).
2. In addition, any object being replaced is also automatically saved, because its foreign key will change too
3. If either of these saves fails due to validation errors, then the assignment statement returns false and the assignment itself is cancelled.
4. If the parent object (the one declaring the has_one association) is unsaved (that is, new_record? returns true) then the child objects are not saved. They will automatically when the parent object is saved.

jordansissel

module Foo
  class Error < StandardError; end
end

module Foo
  class Baz
    def initialize
      puts Error
    end
  end

jwilkins

#!/usr/bin/env ruby
# 25s curl -o all.gz.curl http://download.openwall.net/pub/passwords/wordlists/all.gz
# 11s for this script with 4 parallel requests
require 'typhoeus'

def pfetch(url, splits=4)
  response = Typhoeus.head(url)
  parallelize = false
  basename = File.basename(url)
  size = nil

techniq

from datetime import datetime
from sqlalchemy import Column, Integer, DateTime, ForeignKey
from sqlalchemy.orm import relationship
from sqlalchemy.ext.declarative import declared_attr
from flask_security import current_user


class AuditMixin(object):
    created_at = Column(DateTime, default=datetime.now)
    updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)

inkel

>> /usr/bin/time -l ruby thebench.rb 30 1000
Rehearsal --------------------------------------------------------
fib(30)                0.260000   0.000000   0.260000 (  0.255475)
1000 tempfiles         0.120000   0.250000   0.370000 (  0.429621)
----------------------------------------------- total: 0.630000sec

                           user     system      total        real
fib(30)                0.260000   0.000000   0.260000 (  0.259108)
1000 tempfiles         0.130000   0.270000   0.400000 (  0.848950)

tkrotoff

class Event < ActiveRecord::Base
  include EventJSON

  attr_accessible *EventJSON.attributes

  validates :starts_at, presence: true
  validates :ends_at, presence: true
  validates :all_day, inclusion: { in: [true, false] }
end

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

czottmann

worker:     QUEUE=* bundle exec rake environment resque:work 
scheduler:  bundle exec rake environment resque:scheduler