Browser Wars

Waiting for ie, at least 7, but ideally all of them, to die

Source: StatCounter Global Stats - Browser Market Share

The easiest, fastest and safest way to get your ip address

curl ifconfig.me

thanks to AskUbuntu

Change the db with migrations on the fly

What if you want to add a column though the console with one line of code? (and you exactly know what this implies)

ActiveRecord::Migration.new.add_column :payments, :card_verification, :string, limit: 8
ActiveRecord::Migration.new.execute "full sql here"

Coffescript rendering

The correct way to render html inside your XHR response in Rails.

  app.showFlashMessages('<%=j flash_messages %>')
  $('.booking').replaceWith( '<%=j render @booking %>' )
  app.myFunction( <%=raw array.map(&:to_json) %> ) # TODO: double check

backtrace_silencers to clean the development log from missing assets

# /config/initializers/backtrace_silencers.rb
Rails.backtrace_cleaner.add_silencer { |line| line =~ /lib\/action_dispatch\/middleware\/static.rb/ } if Rails.env.development?

This simple line will clean up your development log to something like this:

[FTL] 
ActionController::RoutingError (No route matches [GET] "/assets/ecoologic/rooms/room_tb.png"):
  actionpack (3.2.5) lib/action_dispatch/middleware/static.rb:62:in `call'

This is only in development (or test?) as you usually don't use the static middleware in staging or production.

mysql cheatsheet

# Print the query result into a file
mysql> select * into outfile '/tmp/new.txt' from users;

# show the current database
mysql> select database();

useful links

• less shitty internet explorer
• Ruby Quick Tips
• jquery vector map
• syntax highlighter
• google analytics and adwords webinars
• HTML5 support
• teach events
• Sublime Text 2 and Ruby on Rails screencast 
• Rspec info
• Capybara matchers
• CDN

get out of the filter bubble

Google personalizes the results of your query and so do many others. In Google this can be avoided adding

&pws=0

to the end of your search URL in the search bar. Useful for SEO.

Disclaimer: You can't get out of all of the filters bubble.

define class methods in ruby (private too)

The following syntax could be used for defining the find method itself, but it is mandatory for alias.

class Item
  def self.find(name)
    # ...
  end

  class << self
    alias :search :find
  end

  private_class_method :find # writing it below private is not enough
end

acronyms

Amazon

EBS - Elastic Block Store
AMI - Amazon Machine Image
EC2 - Elastic Compute Cloud

Web

CDN - Content Delivery Network
ACID - Atomicity Consistency Isolation Durability

import a gem list

If your project doesn't use Gemfile, paste the wanted gemlist in the GEM_LIST string, run this script and that's it. I know, it could be improved, but that's it by now. NOTE: only the first version of the gem is installed, which is the highest.

#!/usr/bin/ruby

gem_list = <<GEM_LIST
actionmailer (2.3.8)
actionpack (2.3.8)
activerecord (2.3.8)
activeresource (2.3.8)
activesupport (2.3.8)
aws-s3 (0.6.3)
barista (1.3.0)
bistro_car (0.2.2)
soap4r (1.5.8)
therubyracer (0.10.2)
will_paginate (2.3.16)
xml-simple (1.1.2)
GEM_LIST

gem_list.split("\n").each do |line|
  gem      = line.match(/^.+? /).to_s # with a space at the end
  versions = line.match(/\(.+\)/)     # surrounded by parenthesis
  highest_version = line.match(/([\d\.]+)/).to_s
  puts `gem install #{gem} -v #{highest_version}`
end

null_store cache for Rails 2

In Rails 3 you can use a fake cache, very useful in development, this uses ActiveSupport::Cache::NullStore, which is not available for Rails 2, but can be easily integrated with some copy and paste with a little customization.

      def initialize
        super # options parameter has been removed 
        extend Strategy::LocalCache
      end

and this is the call

# config/environments/development.rb
require 'vendor/gems/activesupport/cache/null_store.rb' # could also go in environment.rb
# [...]

config.cache_store = :null_store # In Rails 3 it's simply :null 

Update for rails 2.3.18:

Have your file in lib, rather than vendor/gems and have it referenced with full path, something like this:

require "#{Rails.root}/lib/activesupport/cache/null_store.rb"

If every other attempt fail, how about redirecting the cache to dev/null?

config.cache_store = :file_store, "/dev/null"

Ruby 1.9.2 Goodies

[1,2,3].each_with_object(1).map(&:+)
# => [2, 3, 4]

# Same outcome, even shorter
[1, 2, 3].map(&1.method(:+))
# => [2, 3, 4]
# Thanks to rubyquicktips.com

######## even in 1.8
a = [[1,2,3],[2,3,4],[3,4,5]]

# get the union:
a.inject(a.first) { |f,x| f = f | x } # => [1, 2, 3, 4, 5]

# get the intersection:
a.inject(a.first) { |f,x| f = f & x } => [3]

Ruby Koan #183 about scoring project: The Greed Game

When I searched the site for koan greed I was not surprised to see 19 answers and though I've seen very performing implementations, I was quite surprised to see that nobody solved the problem with a class(maybe because about_classes was the next set of koans?), which was my first take. I admit I got lost in refactoring before looking for a comparison, but this is just my spare time.
Here it goes!

class Greed
  def initialize(dice_faces)
    @dice_count = count_occurrences_in(dice_faces)
    @score      = calculate_score!
  end

  attr_reader :score

  def calculate_score!
    @score  = 0
    @score += score_of_triple_1(1000)
    @score += score_of_other_triples(100)
    @score += score_of_5s(50)
    @score += score_of_1s(100)
  end

private

  def score_of_5s(score)
    face_score(5, score)
  end

  def score_of_1s(score)
    face_score(1, score)
  end

  def score_of_other_triples(score_each)
    score_triples score_each, (2..6).to_a
  end

  # >>>>> here starts the meat

  def score_of_triple_1(score)
    score if @dice_count[1] >= 3
  end

  def score_triples(score, faces)
    partial_score = 0
    @dice_count.each_with_index do |times, face|
      next unless faces.include? face
      partial_score += score * face if times >= 3
    end
    partial_score
  end

  # faces counted in triples are escluded
  def face_score(face, score = 0)
    times = @dice_count[face]
    score * (times % 3)
  end

  # <<<<< here ends the meat

  def count_occurrences_in(dice_faces)
    # nil for 0 which is not a face, then the 6 faces
    [nil,0,0,0,0,0,0].tap do |occurrences|
      dice_faces.each { |face| occurrences[face] += 1 }
    end
  end

end


def score(dice)
  # You need to write this method
  Greed.new(dice).score
end

Even considering only "the meat" of my class, the solution on github is still a few lines shorter... Hei, wait, I could implement the sandwitch in score_triple and count_times! I feel like Randy Marshall watching cooking programs!

restrict dates in datepicker with html data attribute

In this fiddle you can see how easy it is to configure a datepicker using the data attribute. Here's the code anyway:

class DateDisabler

  constructor: (@only) ->

  beforeShowDay: (date) =>
    if @only == date.getDate()
      [true, 'available', 'This date is a good date']
    else
      [false, 'unavailable', 'This date is NOT good']


jQuery ->
  $('.datepicker').each (i, e) ->
    dates = $(e).data('only')
    disabler = new DateDisabler dates
    $(e).datepicker({beforeShowDay: disabler.beforeShowDay})

and the haml that calls it:

.datepicker{data: {only: 5}}

Please note the fat arrow in the beforeShowDay, I'll have a look at it soon. Of corse you want it to make it accept an array but that's quite easy and I'm going into it right now. For more complex solutions I recommend gazay/gon, which I know thanks to this railscast

Realex RealVault ActiveMerchant implementation

The following is the extension of the ActiveMerchant gem that will allow the system to store information about the customer and its credit card in realex, typically this is used for recurring payments (in fact it's the name of the pdf provided by Realex), but in our case the need was for charging customers that don't show up at the hotel. It's not the final refactory.

# see: RealVault - Recurring Payments.pdf
module ActiveMerchant::Billing

  class RealVault < RealexGateway
    # 7. on page 24
    URL = 'https://check-doc.cgi'

    # 7.1 (Setup a new Payer)
    # Create a Profile for a payer using payer‐new
    # If the payer exists another one will be stored
    # payer is a hash (see self.test)
    def send_payer(payer, options = {})
      requires! options, :order_id
      request = build_payer_new_request payer, options
      commit request, URL
    end
  
    # 7.2 (Payment method setup)
    # Store the Card details using Card‐New
    # If the card exists another one will be stored
    # card is a ActiveMerchant::Billing::CreditCard
    # options is a hash
    def send_card(card, options)
      requires! options, :order_id
      request = build_card_new_request card, options
      commit request, URL
    end

    # see self.test or send_x methods
    def store!(payer, card, options)
      send_payer_response = send_payer(payer, options)
      send_card_response  = send_card(card, options) if send_payer_response.success?
      
      { :success? => (send_payer_response.success? && send_card_response.success?),
        :send_payer_response => send_payer_response,
        :send_card_response  => send_card_response }
    end

    # ActiveMerchant::Billing::RealVault.test
    # will store the payer and the card in the test account
    # makes a purchase before as suggested by the doc. to make sure auth is ok
    # works out of the box
    def self.test
      timestamp = Time.new.to_s :number
      currency  = 'EUR'
      firstname = 'John'
      surname   = 'Smith'
      payerref  = timestamp
      orderid   = timestamp
      
      rv = ActiveMerchant::Billing::RealVault.new({:password => "pwd",
                                                   :currency => currency,
                                                   :rebate   => "rebate",
                                                   :account  => "internettest",
                                                   :login    => "merchant_id",
                                                   :gateway  => "Realex"})

      card = ActiveMerchant::Billing::CreditCard.new(
                    :number             => 'test_cc_number',
                    :month              => '12',
                    :year               => '2012',
                    :type               => 'visa',
                    :first_name         => firstname,
                    :last_name          => surname,
                    :verification_value => '123')

      payer = { :type      => 'Business',
                :ref       => payerref, # 'smithj01'
                :title     => 'Mr',
                :firstname => firstname,
                :surname   => surname,
                :email     => 'jsmith@acme.com',
                :company   => 'Acme Inc',
                :address   => {
                  :line1   => '123 Fake St.',
                  # :line2
                  # :line3
                  :postcode     => '3',
                  :city         => 'Hytown',
                  :county       => 'Dunham',
                  :country      => 'Ireland',
                  :country_code => 'IE'
                },
                :phonenumbers => {
                  :home   => '55555555',
                  :work   => '+35317433923',
                  :fax    => '+35317893248',
                  :mobile => '+353873748392',
                }
              }

      options = {:order_id => orderid,
                 :currency => currency,
                 :payerref => payer[:ref]}

      rv.purchase 777, card, options
      rv.store! payer, card, options
      # rv.send_payer payer, options
      # rv.send_card card, options
    end

    private

    def build_card_new_request(card, options)
      action    = 'card-new'
      timestamp = Time.now.strftime '%Y%m%d%H%M%S' # same as to_s(:number), but not subjected to override
      orderid   = sanitize_order_id options[:order_id]
      chname    = "#{card.first_name}#{card.last_name}"
      expdate   = card.year.to_s[2..3] + card.month.to_s
      
      sha1      = sha1from "#{timestamp}.#{@options[:login]}.#{orderid}...#{options[:payerref]}.#{chname}.#{card.number}"

      xml       = Builder::XmlMarkup.new :indent => 2
      
      xml.tag! :request, :timestamp => timestamp, :type => action do
        xml.tag! :merchantid, @options[:login]
        xml.tag! :orderid   , orderid
        xml.tag! :card do
          xml.tag! :ref     , card.type + timestamp[3..14]
          xml.tag! :payerref, options[:payerref]
          xml.tag! :number  , card.number
          xml.tag! :expdate , expdate
          xml.tag! :chname  , chname
          xml.tag! :type    , CARD_MAPPING[card_brand(card).to_s]
          xml.tag! :issueno
        end
        xml.tag! :sha1hash, sha1
      end
    end
    
    
    def build_payer_new_request(payer, options)
      action    = 'payer-new'
      timestamp = Time.now.strftime '%Y%m%d%H%M%S' # same as to_s(:number), but not subjected to override
      orderid   = sanitize_order_id options[:order_id]
      sha1      = sha1from "#{timestamp}.#{@options[:login]}.#{orderid}...#{payer[:ref]}"

      xml       = Builder::XmlMarkup.new :indent => 2

      xml.tag! :request, :timestamp => timestamp, :type => action do
    
        xml.tag! :merchantid, @options[:login] 
        xml.tag! :account   , @options[:account]
        xml.tag! :orderid   , orderid

        xml.tag! :payer, :type => payer[:type], :ref => payer[:ref] do
          [:title, :firstname, :surname, :company].each do |tag|
            xml.tag! tag, payer.send('[]', tag)
          end
          xml.tag! :address do
            address = payer[:address]
            [:line1, :line2, :line3, :city, :county, :postcode].each do |tag|
              xml.tag! tag, address.send('[]', tag)
            end
            xml.tag! :country, address[:country], :code => address[:country_code]
          end
          xml.tag! :phonenumbers do
            phonenumbers = payer[:phonenumbers]
            [:home, :work, :fax, :mobile].each do |tag|
              xml.tag! tag, phonenumbers[tag]
            end
          end
          xml.tag! :email, payer[:email]
          xml.tag! :comments do
            xml.tag! :comment, nil, :id => 1 
            xml.tag! :comment, nil, :id => 2 
          end
        end
        xml.tag! :sha1hash, sha1
        xml.tag! :comments do
            xml.tag! :comment, nil, :id => 1 
            xml.tag! :comment, nil, :id => 2 
        end
      end

      xml.target!
    end


  end


end

Unfortunately even the gem itself needed a slight change, due to constant priority order in Ruby (this wouldn't be necessary in java for example):

  # Realex.rb in ActiveMerchant 1.9.4
  # commit method in private section
-      def commit(request)
+      def commit(request, url = URL)

Keeping the environment updated

Use with caution, anyway.

rvm get latest --auto
rvm install 1.9.3
gem update --system # 1.3.7 # that's it for downgrading

gem update bundler  # which I actually keep in my Gemfile
bundle update

Useful Shell commands in Linux (terminal)

find . -name file_name # path first option without equal
grep -rn string . --context=5      # path last

# count the lines of ruby
( find ./ -name '*.rb' -print0 | xargs -0 cat ) | wc -l

rails -e production
rake x:y x:z RAILS_ENV=test # chain tasks and env is loaded only once
rails c production --sandbox 
rails dbconsole -p'whatever'
tailf log/development.log | grep -v ECONNREFUSED -E 'Processing|Render|Parameters' # show actions and templates only
ssh user@host 'ls -l'
scp -C user@host /tmp/db.sql /tmp/db.sql # -C will compress the data over the wire
curl -Lk --user user:pwd --data "param1=value1&param2=value2" http://url
service --status-all
netstat -an | grep "LISTEN " # check the open ports
free -m # check the ram
df -H   # check the disk
curl --user usr:pwd -Lkv --data "param1=value1&param2=value2" www.url.com/post_here
scp -C urs@url:/origin/ destination/ 

ncdu / # disk usage

Git cheatsheet

# Search for a word in log diff
git log -S"def email_required"

# display branches in activity order
git for-each-ref --sort=-committerdate --format='%(committerdate:short) %(refname)' refs/heads refs/remotes 

# checkout previous branch
git checkout -
git checkout @{-1}
# get rid of the latest changes and restore to the sha
git checkout sha1

# undo latest pull
git reset HEAD@{1}
git checkout .

# discard conflicting changes in a dir (after merge)
git co --theirs dir/ # discard their changes
git co --ours dir/   # discard our changes

# stash
git stash save "name of the stash"
git stash apply
git stash help

# checkout a new branch from origin
git checkout -b new origin/new

# tags
git tag "tag-name"
git push --tags

# bisect for debugging
git bisect start
git bisect bad
git co 32c4bf6 # (known good sha)
git bisect good

# create a patch
git format-patch -1 sha1
# and to apply it
git am 0001-commit-name.patch 

# ignore a committed file
# add the file to .gitignore
git rm --cache your_file

# ignore the repo
git update-index --assume-unchanged .ruby-version

# delete a remote branch
git push origin --delete branch_name

# rename a branch
git branch -m old_name new_name

# all your commits on any branch in the last x months
git log --pretty=format:"%ad:%h:%B" --date=short --reverse --all --author=erik  --since=1.day.ago

# count the lines of code of your app
git ls-files app/ | xargs wc -l

# undo a merge that was already pushed:
git revert -m 1 merge_hash
#
#

Here great post on git tips .gitignore_global (add .rbenv-gemsets)

Here's my git config

Git style guide

Best practices 

A Ruby on Rails developer environment

Ryan Bigg's explains how to install Rails, I trust him
Then you'll need postgres

echo "-d=postgresql --skip-bundle -T" > ~/.railsrc
# $ rvm gemset create opera_wbe
# $ gem install bundler --no-rdoc --no-ri

NOTE: the `-T` option will change the `config/application.rb` as this following top group instead of loading `rails/all` (very nice!):

# Pick the frameworks you want:
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "sprockets/railtie"
# require "rails/test_unit/railtie"

module OperaWbe
  class Application < Rails::Application
    # migration with numbers (001, 002, ...) in stead of timestamp
    config.active_record.timestamped_migrations = false

    # in production actually
    # prepend assets path
    # config.action_controller.asset_host = ASSETS_PATH

    # in development actually
    # Remove assets logging
    config.assets.logger = false # ~only~ one line each asset request

# [...]

Also I find the following files very useful

~/.irbrc                     # with global functions to call in the console
~/workspace/.rvmrc           # which loads my @new gemset
~/workspace/every_app/.rvmrc # with the following...

rvm ruby-1.9.2-p290@new # with bundler and rails only
rvm gemdir              # show the gemdir everytime you change project

# .irbrc
puts 'Using irb console helper functions from ~/.irbrc'

# returns the list of methods not inherited from Object
# it will not show methods overwritten from `Object.new`
# eg: `y ml String.new`
def ml(object)
  (String.public_methods - object.methods).sort
end

Then my prompt looks like this:

21:43:02-6950 - ~/workspace> cat ~/.bashrc
[...]
 # some more ls aliases
 alias ll='ls -l'
 alias la='ls -A'
        alias lo='ls -o'


# colorful, with time, history id and path (also in window title)
# export PS1="\[\e]0;\w\a\]\e[1;36m\t-\! - \w>\e[m "
export PS1="\[\e]0;\w\a\e[1;36m\]\t-\! - \w>\[\e[m\] "
# TODO: git branch in prompt


# ror workspace available everywhere
export CDPATH=$CDPATH':/home/erik/workspace/'

## big bash history
export HISTSIZE=20000
# append all commands to the history file, don't overwrite it at the start of every new session
shopt -s histappend

[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm"  # This loads RVM into a shell session.
cd .

And yes, I know, at the moment without without the git branch, it's messing with the color.

echo 'gem: --no-ri --no-rdoc' >~/.gemrc # never install gem doc

A couple of config for git, get the book here

[color]
 diff = true
 status = true
 branch = true

[alias]
 co = checkout

Setup Sublime Text and customize it as such

Scrum, Agile according with @hamids

@hamids has the best introduction video on Scrum I've ever seen.

blogger sucks

Yes it does but it gets better with SyntaxHighlighter, and here is good tutorial to use it As there isn't any easy brush for coffeescript I'm currently using the ruby one, and the javacript one for haml.
brush list

Configuring redis 2.4.7 on Ubuntu 10.04

TODO: this post is still a draft, if you're a visitor, please move on

* install *

the download official page

not enough, then:

AAA! maybe I'd avoid adding it to the auto-execution list, which happens with the following command: sudo update-rc.d redis-server defaults

ijonas.com

run it with: sudo /etc/init.d/redis-server start

* customization *

/etc/sysctl.conf

sysctl vm.overcommit_memory=1 # to avoid reboot