Lucas Caton - English posts

How to run your feature specs using Capybara and Headless Chrome

Thu, 22 Jun 2017 21:03:20 +1000

Google has recently announced a way to run the Chrome browser in a headless environment. If you’re using Capybara gem, you can easily start using headless Chrome. Without further ado, let’s do it:

1) Make sure you have one of the following Chrome versions:

57+ on Linux
59+ on macOS
60+ on Windows

2) Add (or update) the gem selenium-webdriver;

3) Make sure you’re using ChromeDriver version 2.30 or higher. You can install it by running:

brew install chromedriver on macOS;
apt-get install chromium-chromedriver on Debian/Ubuntu Linux.

4) Add the following driver to your spec_helper.rb or rails_helper.rb:

Capybara.register_driver :chrome do |app|
  Capybara::Selenium::Driver.new app, browser: :chrome,
    options: Selenium::WebDriver::Chrome::Options.new(args: %w[headless disable-gpu])
end

Capybara.javascript_driver = :chrome

Done, enjoy headless Chrome! ᕕ( ᐛ )ᕗ

You might get a warning like the following:

WARN Selenium [DEPRECATION] :args or :switches is deprecated. Use Selenium::WebDriver::Chrome::Options#add_argument instead.

Make sure you don’t have another registered driver, I made this mistake myself and had an iphone driver, which was passing args in the old way and turned out to be the reason why I was getting the warning.

How to setup multiple Heroku accounts (for heroku-cli)

Mon, 13 Feb 2017 18:17:00 +1000

Both Heroku and its CLI are great. However, there’s no way to access multiple accounts via terminal out of the box. If you have a personal and a work account and need an easy way to switch between them, I have good news for you! :)

Heroku’s team has created a plugin called heroku-accounts. You can find how to install and how to use in its project page on Github.

To make it even easier, I’ve added the following aliases to my ~/.zshrc (or ~/.bashrc):

# Heroku
alias hp='heroku accounts:set personal'
alias hw='heroku accounts:set work'

Happy hacking!

[Ruby] How to get the name of the calling method?

Fri, 04 Nov 2016 13:36:04 +1000

I was about to run a rake task which would make important changes in my database. My code was similar to this:

def migrate_active_accounts
  accounts = Account.active
  # Code to migrate accounts here...
end

def migrate_inactive_accounts
  accounts = Account.inactive
  # Code to migrate accounts here...
end

This migration was very critical. Thus, I decided to log everything to make sure it would run as expected. So I wrote a separate method to log what accounts were going to run by which method.

In order to do that, I’d need to know which method was calling my logger method.

I ended up finding the answer on StackOverflow (where else would I? :p).

Solution

As usual, Ruby has a neat solution for it: Kernel module has a caller_locations method, which returns an array with the current execution stack. So all we need to do is to use caller_locations.first.label to get the first element from the stack and then get its label.

My final code was looking like the following:

def migrate_active_accounts
  accounts = Account.active
  log_migration_info(accounts)

  # Code to migrate accounts here...
end

def migrate_inactive_accounts
  accounts = Account.inactive
  log_migration_info(accounts)

  # Code to migrate accounts here...
end

private

def log_migration_info(accounts)
  caller_method = caller_locations.first.label

  Rails.logger.info "Running [MyClass##{caller_method}]
    for the following accounts: #{accounts.map(&:id).to_sentence}"
end

Ruby prior to 2.0

If you’re using an old version of Ruby (even though you shouldn’t), you’ll need to use caller method along with a regular expression:

caller.first[/`(.*)'/, 1]

Happy hacking!

New blog theme

Fri, 04 Nov 2016 11:11:54 +1000

Last time I updated this blog’s theme was in 2012!

It was about time to have a fresh new look and there you have it! \o/

Prevent Rails from writing development/test log files

Thu, 27 Oct 2016 10:44:27 +1000

I can’t remember the last time I needed to open/read log/development.log or log/test.log. These files usualy just consume disk space unnecessarily (some test.log files can easily reach more than 1 GB).

After talking to some other developers, all of them agreed they don’t use it as well. So what I’ve been doing in my projects is adding the following code (note that it’ll still display logs through the STDOUT though):

Rails 4+

config/environments/development.rb:

# Prevents from writing logs on `log/development.log`
logger           = ActiveSupport::Logger.new(STDOUT)
logger.formatter = config.log_formatter
config.logger    = ActiveSupport::TaggedLogging.new(logger)

config/environments/test.rb:

# Prevents from writing logs on `log/test.log`
config.log_level = :warn
logger           = ActiveSupport::Logger.new(STDOUT)
logger.formatter = config.log_formatter
config.logger    = ActiveSupport::TaggedLogging.new(logger)

Rails 3

config/environments/development.rb:

# Prevents from writing logs on `log/development.log`
logger        = ::Logger.new(STDOUT)
config.logger = ActiveSupport::TaggedLogging.new(logger)

# Replace `config.active_support.deprecation = :log` with:
config.active_support.deprecation = :stderr

config/environments/test.rb:

# Prevents from writing logs on `log/test.log`
config.log_level = :warn
logger           = ::Logger.new(STDOUT)
config.logger    = ActiveSupport::TaggedLogging.new(logger)

Ps.: I’ve sent a suggestion to rubyonrails-core mailing list to make it default from next Rails versions, let’s see their thoughts.

Puma vs. Unicorn

Sun, 13 Mar 2016 14:24:26 +1000

TL; DR - Just use Puma.

Rails has changed its default server from Webrick to Puma in Rails 5!

It also supports Action Cable (one of the new features from Rails 5) and Basecamp said they’re using Puma in production.

I was wondering if Puma has been in fact better than Unicorn so I’ve read some blog posts about it:

Basically, the answer is yes - it is a bit better, but don’t wait for a huge improvement.

It’d be a good idea if you’re either about to start a new project and migrating your current project to Rails 5 or newer.

Rake task to import a production DB dump

Sat, 12 Mar 2016 09:45:52 +1000

Every now and then I need to write a script (rake task) to import a production database dump.

This is code I usually use:

require 'yaml'

namespace :db do
  desc 'Downloads and imports a production DB dump'
  task :import_production_dump do
    puts '➙ Generating production DB dump...'
    execute_on_server %(
      PGPASSWORD="`cat /var/www/project/current/config/database.yml | \
        grep password | awk '{ print $2 }'`" \
        pg_dump database_name -h custom_url.rds.amazonaws.com -U user_name \
        --column-inserts --no-owner --no-privileges > backup.sql
    )

    puts '➙ Downloading production DB dump...'
    system "scp #{server_user_and_host}:#{backup_file_name} ."

    puts '➙ Deleting production DB dump...'
    execute_on_server "rm #{backup_file_name}"

    puts '➙ Cleaning your local DB...'
    %w[drop create].each { |task| Rake::Task["db:#{task}"].invoke }

    puts '➙ Importing production DB dump...'
    system "bin/rails db development < #{backup_file_name} > /dev/null"

    puts '➙ Removing local dump...'
    system "rm #{backup_file_name}"

    puts '➙ Done!'
  end

  def execute_on_server(commands)
    system %(ssh -T #{server_user_and_host} << 'SSH'
      #{commands}
    SSH).split("\n").map(&:strip).join("\n")
  end

  def server_user_and_host
    'username@example.com'
  end

  def backup_file_name
    'backup.sql'
  end
end

Let me know in the comments if you have a better solution! Perhaps a small gem? :)

Why I regenerated my SSH key and maybe you should too

Tue, 23 Feb 2016 18:55:15 +1000

I think we all agree it’s a good practice to regenerate your SSH key from time to time. Not sure about you, but the first thing that comes to my mind when I think about that is: it’d take forever to replace my key in all servers I need to access, all online services that use my key, etc.

Overcoming my laziness, I decided at least to list those place it turned out it was a small list:

Servers
Github
BitBucket

Although now it looks more reasonable, I was still lazy to do it. But then I noticed that Github recommends the use of HTTPS instead of SSH for Git repositories syncs:

What does one thing have to do with another? Well, by using HTTPS, you don’t need to upload your SSH key to Github (check this out: mine isn’t longer at Github).

BitBucket also supports it, which means I’d be able to regenerate my SSH key without having to upload it again to these services.

Servers

What’s left? Servers! From now on, every time I realise it’s time to regenerate my SSH key, all I need to update are the servers. I ended up making a list of servers that I’d need to update and found out in the end it wasn’t a big list and it’d be way easier than I thought it would.

Let’s face the truth: I had been using the same SSH key in the last 5 years or so and it’d be totally worth it to ensure my security as well as the security of the projects from the company I work for.

Becoming safer

There’s more! This is the interesting part of this post: I’ve changed other things that made everything even safer:

My new SSH key uses 4096 bits - recommended by Github - instead of the default (2048 bits).
As I mentioned before, I’ve changed all my local repositories to use HTTPS instead of SSH (see how in the end of this post).
I’m now using a personal access token rather than my Github password (you can create it here), along with two-factor authentication, which I was already using.
Cool, but would I need to type this token every time? Nope. There’s a nifty tool called ssh-agent that can save your token. If you’re using macOS, it’s even easier: Keychain can save and encrypt your token for you.
My SSH key now has a passphrase, also saved encrypted on macOS’s Keychain, which means I don’t need to type it every time either.

HTTPS is faster!

According to some tests I made here, HTTPS is faster than SSH:

# SSH
$ time git clone git@github.com:rails/rails.git
# 24.28s user 9.56s system 49% cpu 1:08.20 total

# HTTPS
$ time git clone https://github.com/rails/rails.git
# 13.52s user 6.41s system 39% cpu 50.730 total

In order to use HTTPS in my Git repos, do I need to re-clone every project?

Nope. Just open .git/config file and replace:

url = git@github.com:username/repo.git

with:

url = https://github.com/username/repo.git

Conclusion

Regenerating your SSH key every now and then isn’t as painful as you might think. I’d recommend doing it every 3 years or even less if you’re paranoic or you work on something critic.

What is "frozen_string_literal" in Ruby?

Tue, 19 Jan 2016 09:33:30 +1000

Freezing Strings feature improves apps performance by freezing Strings. So, Matz - Ruby’s creator - decided to make all String literals frozen (immutable) by default in Ruby 3.0.

In order to have a transition path to this coming big change, it was decided to have a magic comment at the beginning of files, so you can use in Ruby 2.x. To do so, just add this comment in the first line of your files:

# frozen_string_literal: true
class YourClass
  # ...
end

Try adding it to your spec_helper or rails_helper file and let me know in the comments if your performance gets any better.

More info: Ruby issue #8976.

If you really need to create a monkey patch, do it properly

Thu, 10 Dec 2015 15:15:44 +1000

Sometimes we need to create a monkey patch for a gem or external lib. In these cases, it’s good to force it to fail if the gem has been bumped up. Let’s use Paperclip as an example:

if Paperclip::VERSION != '1.2.3'
  # If you see this message, please test removing this file
  # If it's still required, please bump up the version above
  fail 'Please remove me, Paperclip version has changed'
end

If the gem doesn’t provide you the version through a method, you can solve it with:

if Bundler.load.specs.find { |gem| gem.name == 'paperclip' }.version.to_s != '1.2.3'
  # If you see this message, please test removing this file
  # If it's still required, please bump up the version above
  fail 'Please remove me, Paperclip version has changed'
end

Or even when you’re waiting for a new Rails version, e.g.:

fail 'Remove this file' if Rails::VERSION::MAJOR >= 5

CampJS 2014 - the best geek event I ever attended

Fri, 21 Nov 2014 01:11:04 +1000

A few days ago I was in CampJS, the best geek event I ever attended.

This is the official website (which is pretty cool by the way): http://campjs.com/.

Why it was the best in my opinion:

It happened at an amazing place - close to the nature and changing the usual environment is renewable. I’d definitely recommend it!
I had the chance to talk to a lot of other Javascript developers
Awesome talks and workshops
Good food and beers
A live podcast was recorded in there

A friend of mine (@erikEcoologic) has written an awesome blog post about the event, so check it out! ;)

A special thanks to @brucestronge and to NetEngine for the tickets!

Video & some pictures

How to use command line on macOS

Sun, 31 Aug 2014 21:49:02 +1000

A friend of mine (who used to use Windows) has bought a Mac recently and he asked me how to use the command line on macOS:

My answer was:

99% of commands are identical in Linux. This is good news as there are a lot of material about it available on the Internet;
Terminal.app from macOS is cool, but it’s not perfect. I (and 90% of developers I know) use iTerm2 (http://iterm2.com/). It’s light (3mb), free, open-source, has a better interface than the native one and it rocks! Best terminal I’ve ever used.
This is the most useful topic in my answer: an awesome cheat-sheet with command line commands made by the Git-tower team;
To finish: I’ve recorded a screencast (in Portuguese) explaining how to create scripts on macOS and Linux (similar to BAT files on Windows).:

What's on my macOS menu bar

Sun, 10 Aug 2014 20:56:30 +1000

Application	Description	Type
Caffeine	Prevent your Mac from automatically going to sleep, dimming the screen or starting screen savers	Free
ColorSnapper	Color picker	Paid
1Password	Password manager	Paid
Dropbox	File hosting service	Free / Paid
CrashPlan	Online data backup in real time	Paid
Spectacle	Window control	Free / Open source
Evernote	Although Evernote is great, I don't use this icon at all.When I close it, it returns automatically ¯\_(ツ)_/¯	Free / Paid
Chrome notifications	I never really use it, but I guess there's no way to remove it though	Free
Text Expander	Custom keyboard shortcuts into frequently-used texts	Paid
AirPlay	Play content on your TV via Apple TV	Free
Time Machine	Built-in backup feature of macOS that works with an external HD or Time Capsule	Free

An awesome Wiki built with Ruby and Rails!

Sat, 05 Apr 2014 04:14:53 +1000

I’ve been worked on a small open-source project. I’m talking about ruby_wiki, a simple wiki built with Ruby on Rails:

If you’re interested, feel free to fork and contribute to the project.

Have a Rails 2 app? You can run it on the newest Ruby!

Fri, 28 Feb 2014 10:36:17 +1000

Do you have a legacy Rails application which is still running on Rails 2?

There are several reasons to migrate your application to new Rails versions, like to improve the security, to be able to use a better syntax, to take advantage of new features and also because most of current gems will only work on Rails 3 or higher. However, sometimes it’s hard to do that, especially for big projects. And certainly today there’re many project still running on Rails 2.

But there’s one good thing you can (and should) do! I’m talking about to use the newest Ruby version. Yes, I’m serious. When I wrote this post, the current Ruby version was 2.1.1 - and it’s not so hard to get it working fine with Rails 2.

Obviously, would be better if you have a good test coverage.

That said, let’s do it in a few steps:

Replacements

Gemfile

Rails 2 apps don’t use Bundler by default, so if you don’t have Bundler managing your gems yet, you should check here how to do that.

## There's no way to ensure that the next Ruby versions will work,
## but so far the current one works fine:
ruby '2.1.1'
## The same for rake:
rake '10.1.1'
## You might need the iconv gem:
gem 'iconv'

Rakefile

## Replace:
## require 'rake/rdoctask'
## with:
require 'rake/task'

config.ru

## Replace:
## require 'config/environment'
## with:
require File.dirname(__FILE__) + '/config/environment'

FasterCSV ➙ CSV

Replace all FasterCSV constants with CSV. Also, include require 'csv' to relevant files (or include the require to your config/environment.rb file).

Inclusions

config/environment.rb

## Include this before the `Rails::Initializer.run` line:
if RUBY_VERSION >= '2.0.0'
  module Gem
    def self.source_index
      sources
    end
    def self.cache
      sources
    end
    SourceIndex = Specification
    class SourceList
      # If you want vendor gems, this is where to start writing code.
      def search(*args); []; end
      def each(&block); end
      include Enumerable
    end
  end
end

config/initializers/paperclip.rb

## The patches below are needed when using an old version of PaperClip + Ruby 2.x
## https://github.com/thoughtbot/paperclip/issues/262
## https://github.com/thoughtbot/paperclip/commit/1bcfc14388d0651c5fc70ab9ca3511144c698903

module Paperclip
  class Tempfile < ::Tempfile
    def make_tmpname(basename, n)
      extension = File.extname(basename)
      sprintf('%s,%d,%d%s', File.basename(basename, extension), $$, n.to_i, extension)
    end
  end
end

module IOStream
  def to_tempfile
    name = respond_to?(:original_filename) ? original_filename : (respond_to?(:path) ? path : 'stream')
    tempfile = Tempfile.new(['stream', File.extname(name)])
    tempfile.binmode
    self.stream_to(tempfile)
  end
end

New files

config/initializers/ruby2.rb

## This is a very important monkey patch to make Rails 2.3.18 to work with Ruby 2+
## If you're thinking to remove it, really, don't, unless you know what you're doing.

if Rails::VERSION::MAJOR == 2 && RUBY_VERSION >= '2.0.0'
  module ActiveRecord
    module Associations
      class AssociationProxy
        def send(method, *args)
          if proxy_respond_to?(method, true)
            super
          else
            load_target
            @target.send(method, *args)
          end
        end
      end
    end
  end
end

config/initializers/rails_generators.rb

It’ll prevent Rails migration generator from stop working, otherwise you’ll receive the following error message:

undefined local variable or method `vars' for # Rails::Generator::Commands::Create

(Thanks to Mr. S and jnwheeler44 for helping me to fix this one)

## This is a very important monkey patch to make Rails 2.3.18 to work with Ruby 2+
## If you're thinking to remove it, really, don't, unless you know what you're doing.

if Rails::VERSION::MAJOR == 2 && RUBY_VERSION >= '2.0.0'
  require 'rails_generator'
  require 'rails_generator/scripts/generate'

  Rails::Generator::Commands::Create.class_eval do
    def template(relative_source, relative_destination, template_options = {})
      file(relative_source, relative_destination, template_options) do |file|
        # Evaluate any assignments in a temporary, throwaway binding
        vars = template_options[:assigns] || {}
        b = template_options[:binding] || binding

        # this no longer works, eval throws "undefined local variable or method `vars'"
        # vars.each { |k, v| eval "#{k} = vars[:#{k}] || vars['#{k}']", b }
        vars.each { |k, v| b.local_variable_set(:"#{k}", v) }

        # Render the source file with the temporary binding
        ERB.new(file.read, nil, '-').result(b)
      end
    end
  end
end

RSpec

Make sure you’re using the last compatible version with Rails 2.3.18:

gem 'rspec', '1.3.2'
gem 'rspec-rails', '1.3.4'

Remove the file script/spec
Remove the following lines from the lib/tasks/rspec.rake file:

```ruby gem ‘test-unit’, ‘1.2.3’ if RUBY_VERSION.to_f >= 1.9

rspec_gem_dir = nil

Dir[”#{Rails.root}/vendor/gems/*”].each do |subdir| rspec_gem_dir = subdir if subdir.gsub(“#{Rails.root}/vendor/gems/”,””) =~ /^(\w+-)?rspec-(\d+)/ && File.exist?(“#{subdir}/lib/spec/rake/spectask.rb”) end

rspec_plugin_dir = File.expand_path(File.dirname(FILE) + ‘/../../vendor/plugins/rspec’)

if rspec_gem_dir && (test ?d, rspec_plugin_dir) raise “\n#{‘‘50}\nYou have rspec installed in both vendor/gems and vendor/plugins\nPlease pick one and dispose of the other.\n#{‘‘50}

Interesting script written in Ruby: "The Globe"

Fri, 19 Apr 2013 20:35:03 +1000

I’ve just found this amazing Ruby script!

In order to run it yourself, just create a Ruby file called a.rb with the following content:

v=0000;eval$s=%q~d=%!^Lcf<LK8,                  _@7gj*LJ=c5nM)Tp1g0%Xv.,S[<>YoP
4ZojjV)O>qIH1/n[|2yE[>:ieC       "%.#%  :::##"       97N-A&Kj_K_><wS5rtWk@*a+Y5
yH?b[F^e7C/56j|pmRe+:)B     "##%      ::##########"     O98(Zh)'Iof*nm.,$C5Nyt=
PPu01Avw^<IiQ=5$'D-y?    "##:         ###############"    g6`YT+qLw9k^ch|K'),tc
6ygIL8xI#LNz3v}T=4W    "#            #.   .####:#######"    lL27FZ0ij)7TQCI)P7u
}RT5-iJbbG5P-DHB<.   "              ##### # :############"   R,YvZ_rnv6ky-G+4U'
$*are@b4U351Q-ug5   "              #######################"   00x8RR%`Om7VDp4M5
PFixrPvl&<p[]1IJ   "              ############:####  %#####"   EGgDt8Lm#;bc4zS^
y]0`_PstfUxOC(q   "              .#############:##%   .##  ."   /,}.YOIFj(k&q_V
zcaAi?]^lCVYp!;  " %%            .################.     #.   "  ;s="v=%04o;ev"%
(;v=(v-($*+[45,  ":####:          :##############%       :   "  ])[n=0].to_i;)%
360)+"al$s=%q#{  "%######.              #########            "  ;;"%c"%126+$s<<
126}";d.gsub!(/  "##########.           #######%             "  |\s|".*"/,"");;
require"zlib"||  "###########           :######.             "  ;d=d.unpack"C*"
d.map{|c|n=(n||  ":#########:           .######: .           "  )*90+(c-2)%91};
e=["%x"%n].pack   " :#######%           :###### #:          "   &&"H*";e=Zlib::
Inflate.inflate(   "  ######%           .####% ::          "   &&e).unpack("b*"
)[0];22.times{|y|   "  ####%             %###             "   ;w=(Math.sqrt(1-(
(y*2.0-21)/22)**(;   " .###:             .#%             "   ;2))*23).floor;(w*
2-1).times{|x|u=(e+    " %##                           "    )[y*z=360,z]*2;u=u[
90*x/w+v+90,90/w];s[(    " #.                        "    ;y*80)+120-w+x]=(""<<
32<<".:%#")[4*u.count((     " .                   "     ;"0"))/u.size]}};;puts\
s+";_ The Qlobe#{" "*18+ (       "#  :#######"       ;"Copyright(C).Yusuke End\
oh, 2010")}";exit~;_ The Qlobe                  Copyright(C).Yusuke Endoh, 2010

Then, run the following line on your terminal:

while true; do clear; ruby a.rb | tee b.rb; sleep 0.2; mv -f b.rb a.rb; done

Via d.hatena.ne.jp

Hellо, I am a compiler

Sat, 23 Feb 2013 11:37:55 +1000

I’ve found the following text here and thought it’d be nice to share it with you. Hope you enjoy it as much as I did :)

Hellо, I am a compiler.

I just scanned thousands of lines of code while you were reading this sentence. I browsed through millions of possibilities of optimizing a single line of yours using hundreds of different optimization techniques based on a vast amount of academic research that you would spend years getting at. I won’t feel any embarrassment, not even a slight ick, when I convert a three-line loop to thousands of instructions just to make it faster. I have no shame to go to great lengths of optimization or to do the dirtiest tricks. And if you don’t want me to, maybe for a day or two, I’ll behave and do it the way you like. I can transform the methods I’m using whenever you want, without even changing a single line of your code. I can even show you how your code would look in assembly, on different processor architectures and different operating systems and in different assembly conventions if you’d like. Yes, all in seconds. Because, you know, I can; and you know, you can’t.

P.S. Oh, by the way you weren’t using half of the code you wrote. I did you a favor and threw it away.

Getting root permission to change a file without leaving Vim

Fri, 22 Feb 2013 15:33:41 +1000

You know when you open a file on Vim and after some changes you realise you’d need root permission to save the changes?

I used to think that there isn’t other way other than:

Copy the content of the file
Close Vim
Re-open it with sudo
And finally paste it again

It might be a bit harder if you’re using Vim on a remote SSH session.

Well, it will no longer be a problem. Today I learned a neat way to achive the same thing:

:w !sudo tee %

Thanks my friend Diogo Lisboa for the tip.

A simple way to deploy your Rails applications

Fri, 25 Jan 2013 19:24:40 +1000

When I have a very simple Rails app, I avoid adding Capistrano or any other complex tool to deploy it.

Instead, I use a simple shell script, which access the server via SHH and do what needs to be done:

#! /bin/bash
# script/deploy.sh

TAG=deployed_at_$(date +"%F_%H-%M")

git tag -m '' -a $TAG
git push --tags

ssh user@your_domain.com << 'SSH'
  cd /var/rails_apps/my_app
  rm -rf public/assets
  git pull
  bundle install --without development test
  bundle exec rake db:migrate db:seed assets:clean assets:precompile
  touch tmp/restart.txt
  git describe > public/version
SSH

After that, a tag will be created in the git repository. Now, you know exactly the date and time when it was deployed.

Also, you can find out which version (tag from git) is in production by accessing the URL http://your_domain.com/version.

Update from March 8, 2013:

I’ve created another script which accepts a -q (quick) flag:

```sh #! /bin/bash

script/deploy.sh

create_tag(){ TAG=deployed_at_$(date +”%F_%H-%M”)

git tag -m ‘’ -a $TAG git push –tags }

quick_deploy(){ echo ‘Starting quick deploy…’

create_tag

ssh yourserver.com « ‘SSH’ cd /var/rails_apps/app_name git pull bundle install –without development test touch tmp/restart.txt git describe > public/version SSH }

complete_deploy(){ echo ‘Starting complete deploy…’

create_tag

ssh yourserver.com « ‘SSH’ cd /var/rails_apps/app_name rm -rf public/assets git pull bundle install –without development test bundle exec rake db:migrate db:seed assets:clean assets:precompile touch tmp/restart.txt git describe > public/version SSH }

if [ $1 ]; then if [ “$1” == ‘-q’ ] || [ “$1” == ‘–quick’ ]; then quick_deploy else echo -e ‘Usage: script/deploy [OPTIONS]

An easy way to split windows in Vim

Thu, 03 Jan 2013 11:22:32 +1000

There are several ways to split windows in Vim.

This one is now my favorite:

New blog layout

Tue, 02 Oct 2012 14:08:09 +1000

I’ve finally changed my blog theme.

This one is cleaner, I hope y’all enjoy it :)

How to test ElasticSearch in a Rails application

Wed, 01 Aug 2012 10:50:11 +1000

When I started using ElasticSearch in my Rails applications, I had a problem to create separate indexes for the automated tests.

The problem was: there is no way to create more than one database in ElasticSearch. You can create different indexes, but no different databases.

Even creating indexes with different names won’t solve the problem: it’s necessary to configure our Rails models in order to work with a different index name when the tests are running.

I’m using both tire and RSpec gems. In this post, I’ll explain how to separate indexes for development and test environments.

First of all, I’ve included the code below in file config/initializers/tire.rb:

if Rails.env.test?
  prefix = "#{Rails.application.class.parent_name.downcase}_#{Rails.env.to_s.downcase}_"
  Tire::Model::Search.index_prefix(prefix)
end

And I’ve manually set the index name in the model (assuming there is a Movie model):

index_name "#{Tire::Model::Search.index_prefix}movies"

Done! With that, the index name will be movies in development environment and appname_test_movies in test environment.

Deleting test indexes

In order to delete the test indexes after the suite has finished running, just add the following code to file spec/integration_helper.rb (or similar):

RSpec.configure do |config|
  config.after(:all, type: :request) { delete_movie_index }
end

And create a custom macro, which will delete the indexes:

def delete_movie_index
  Movie.index.delete
end

Demo app

I created a small application to demonstrate the technique explained in this post:

https://github.com/lucascaton/elasticsearch_app_example

I hope it helps!

Pair programming with tmux

Wed, 11 Jul 2012 17:39:00 +1000

Server:

tmux -2 -S /tmp/pair new-session -s PairProgramming
chmod 777 /tmp/pair

Client:

tmux -2 -S /tmp/pair attach-session -t PairProgramming

Replacing "Selenium" with "Poltergeist"

Thu, 14 Jun 2012 22:13:15 +1000

My friend @pellegrino gave me an awesome tip: to replace “Selenium” with “Poltergeist”. For those who don’t know, Poltergeist is a PhantomJS driver for Capybara. I’ve done it in some projects and it works very well!

In order to do it, include the gem to your Gemfile:

gem 'poltergeist'

Update your Capybara configuration:

Capybara.configure do |config|
  # config.javascript_driver = :selenium
  config.javascript_driver = :poltergeist
end

Run the specs!

If you are testing some confirm() JavaScript method and you have a code similar to page.driver.browser.switch_to.alert.accept, you’ll get this error:

undefined method `switch_to'

While I was trying to fix it, I found out that Poltergeist always returns true from window.confirm. There’s no way (at the moment) to make it return false, but at least it won’t prevent your test from passing: all I had to do was to remove that particular line and it solved the issue.

This is the results from the first project I’ve migrated:

Before: Finished in 1 minute 35.45 seconds
After: Finished in 41.03 seconds

Hope you find it helpful as I did!

My dotfiles

Sun, 29 Apr 2012 22:11:02 +1000

I’ve finally created a repository with my dotfiles. Dotfiles are configurations files, usually with their names beginning with a dot (hidden files) and located on your home folder (~/).

You can check it out here: github.com/lucascaton/dotfiles

Regex to match Youtube URLs (using Ruby)

Tue, 10 Apr 2012 11:19:34 +1000

I’ve created a regular expression in order to match Youtube URLs. As Youtube URLs starts with https://youtube.com and https://youtu.be, the following regex solves the problem:

/^(?:https?:\/\/)?(?:www\.)?youtu(?:\.be|be\.com)\/(?:watch\?v=)?([\w-]{10,})/

This regex will match:

http://youtube.com/watch?v=1234567890
https://youtube.com/watch?v=1234567890
http://www.youtube.com/watch?v=1234567890
http://www.youtube.com/watch?v=12345-67890
https://www.youtube.com/watch?v=1234567890
http://youtu.be/1234567890
https://youtu.be/1234567890
http://www.youtu.be/1234567890
https://www.youtu.be/1234567890
http://www.youtube.com/watch?v=1234567890&feature=context&context=G2de15aaFAAAAAAAAAAA
www.youtube.com/watch?v=1234567890
youtube.com/watch?v=1234567890
youtu.be/1234567890

But it won’t match:

youtube.com
youtube.com/
youtube.com/watch
youtube.com/watch/
youtu.be
youtu.be/

How to remove several lines in the Vim editor using Regex

Tue, 06 Sep 2011 10:31:28 +1000

A quick tip for those who use Vim: if you need to remove several lines that match your regular expression, you can achive that by running

:g /pattern/d

Let’s say you want to remove the commented lines from the following file:

# This is a comment
def foo
end

# This is another comment
def bar
end

Run :g /^#.*/d and your code will become:

def foo
end

def bar
end

Simple, hey? :)

My new gem "code2pdf"

Thu, 02 Jun 2011 16:11:18 +1000

I’ve created a gem called code2pdf, which is a simple and open-source tool to convert your codebase to a PDF file. It might be especially useful in case you need to register you software.

In order to install it, just run:

gem install code2pdf

Then, open a terminal and run:

code2pdf [project path] [blacklist file]

The blacklist file is optional and must be a YML file, similar to the following:

:directories:
  - .git
  - log
  - public/system
  - spec
  - tmp
  - vendor

:files:
  - .DS_Store
  - .gitignore
  - database.yml
  - favicon.ico

You can find more information (including a PDF output example in the repository:

github.com/lucascaton/code2pdf

Please, let me know in the comments if you like it :)

My Vimfiles

Tue, 24 May 2011 20:36:18 +1000

Vimfiles are configuration files for the Vim editor. It includes the editor preferences, theme (color scheme), fonts, plugins, custom functions, and more.

I’ve finally created my own from scrach, which you can find here:

github.com/lucascaton/vimfiles

How to test Rails mailers using RSpec

Mon, 25 Oct 2010 19:19:04 +1000

ActionMailer module has been reconstructed in Rails 3 and mailers have their own subdirectory (app/mailers) since then.

This blog post will demostrate how to test them in Rails using RSpec. Assuming that we have a mailer like the following:

class Notifier < ActionMailer::Base
  default from: 'noreply@company.com'

  def instructions(user)
    @name = user.name
    @confirmation_url = confirmation_url(user)

    mail to: user.email, subject: 'Instructions'
  end
end

To send an email through a method from User model:

class User
  def send_instructions
    Notifier.instructions(self).deliver_now
  end
end

Before test it, make sure the config/environments/test.rb file has the following configuration:

Rails.application.configure do
  config.action_mailer.delivery_method = :test
end

It ensures that emails won’t be sent, but instead be stored on ActionMailer::Base.deliveries array.

So, in order to create the tests:

# spec/models/user_spec.rb

RSpec.describe User, type: :model do
  subject { create :user }

  it 'sends an email' do
    expect { subject.send_instructions }
      .to change { ActionMailer::Base.deliveries.count }.by(1)
  end
end

# spec/mailers/notifier_spec.rb

RSpec.describe Notifier, type: :mailer do
  describe 'instructions' do
    let(:user) { mock_model User, name: 'Lucas', email: 'lucas@email.com' }
    let(:mail) { described_class.instructions(user).deliver_now }

    it 'renders the subject' do
      expect(mail.subject).to eq('Instructions')
    end

    it 'renders the receiver email' do
      expect(mail.to).to eq([user.email])
    end

    it 'renders the sender email' do
      expect(mail.from).to eq(['noreply@company.com'])
    end

    it 'assigns @name' do
      expect(mail.body.encoded).to match(user.name)
    end

    it 'assigns @confirmation_url' do
      expect(mail.body.encoded)
        .to match("http://aplication_url/#{user.id}/confirmation")
    end
  end
end

Rails allows you to create very comprehensive tests for mailers.

Happy coding!