Sinatra on Nginx on Ubuntu on Passenger

Just wanted to share our setup, as reminder and help for others 😉

(do not forget to create a tmp and public folder inside your projects folder)

#/opt/nginx/conf/nginx.conf
server {
  listen 80;
  server_name xxx.yyy.com;

  access_log /var/log/xxx_access.log  main;
  error_log /var/log/xxx_error.log debug;
  root /srv/xxx/public;   # <--- be sure to point to 'public'!
  passenger_use_global_queue on;
}

#/etc/hosts
127.0.0.1       xxx.yyy.com

#config.ru
require 'app'
disable :run
set :root, Pathname(__FILE__).dirname
run Sinatra::Application

#app.rb
require 'rubygems'
require 'sinatra'

get "/" do
  "Hello world from xxx"
end

ActiveRecord without default scope

This is a pretty hacky implementation of the feature we needed:
remove the default scope for some queries (e.g. update deleted records)

Code:

class ActiveRecord::Base
  def self.without_default_scope(&block)
    scope = scoped({})
    defaults = scope.current_scoped_methods_when_defined

    old = defaults[:find][:conditions]
    defaults[:find][:conditions] = {}

    begin
      yield(scope)
    ensure
      defaults[:find][:conditions] = old
    end
  end
end

Usage

MYModel.without_default_scope{|s| s.update_all(:deleted_at => nil)}

There is an less hacky alternative, but it did not work for us (AR 2.3.2)

Check if a numer is a power of 2 in ruby

~~The~~ One imo not-so-obvious solution is:

# 0 -> false, 1->true, 2->true, 3->false ...
n.to_s(2).scan(/1/).size == 1

And why it works is an exercise for the reader 😉

Update:
A crazy benchmark comparing different versions of power of 2 algorithms by reto
The fastest, still readable versions is:

n & (n – 1) == 0
... followed by ...
Math.log(n) / Math.log(2) % 1 == 0

Simple nested_layout for rails

There are some 40loc nested layout monsters on the interwebs, but it can be as simple as…

# application_helper.rb
def nested_layout(layout, &block)
  @content_for_layout = capture(&block)
  concat(render :file => layout)
end

# layouts/xxxx.erb
<% nested_layout 'layouts/application' do %>
  Im nested...
  <%= yield %>
<% end %>

Joined environment file for production and staging

Often production and staging share much, so why not use a common file for that…

#config/environments/production.rb and config/environments/staging.rb
eval(File.read("#{File.dirname(__FILE__)}/production_like.rb"))
...environment specific code ...

#config/environments/production_like.rb
config.cache_classes = true
...

the File.read/eval is rather hacky, but works nevertheless 😉

Michael Grosser, the Blog

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