humanzz

# This is a port of the javascript code found in the following link
#http://groups.google.com/group/Google-Maps-API/browse_thread/thread/a45947d72c27cc73

class Mercator
  #offset is defined at zoom level 21 which means that this Mercator is valid for 21 zoom levels
  OFFSET = 268435456
  RADIUS = OFFSET / Math::PI
  
  def self.lng_to_x(lng, zoom)
    (OFFSET + RADIUS * lng * Math::PI / 180).to_i >> (21 - zoom)

banker

# with multiple collections + commands for renaming back the collections

require 'mongo'

# Stop writing to your database.
# Then, for each collection:
# Specify the DB and COLLECTION you want to convert.
# Will insert all modified documents into a new collection
# called 'new_' + old_collection_name.
# Then you can delete the old collection and rename the new one

jcasimir

Transactions

As your business logic gets complex you may need to implement transactions. The classic example is a bank funds transfer from account A to account B. If the withdrawal from account A fails then the deposit to account B should either never take place or be rolled back.

Basics

All the complexity is handled by ActiveRecord::Transactions. Any model class or instance has a method named .transaction. When called and passed a block, that block will be executed inside a database transaction. If there's an exception raised, the transaction will automatically be rolled back.

Example

tokland

require 'active_record'
require 'arel'

# Ruby-like syntax in AR conditions using the underlying Arel layer (Rails >= 3.0).
#
# What you would usually write like this: 
#
#   User.where(["users.created_at > ? AND users.name LIKE ?", Date.yesterday, "Mary"])
#
# can now be written like this (note those parentheses required by the operators precedences):

billie66

# This file should be placed on the directory of ~/blog/config

upstream unicorn {
    server unix:/tmp/unicorn.todo.socket fail_timeout=0;
}

server {
  listen                80 default;
  #server_name          example.com;
  root                  /home/username/blog/public;

markbates

If you're writing web applications with Ruby there comes a time when you might need something a lot simpler, or even faster, than Ruby on Rails or the Sinatra micro-framework. Enter Rack.

Rack describes itself as follows:

Rack provides a minimal interface between webservers supporting Ruby and Ruby frameworks.

Before Rack came along Ruby web frameworks all implemented their own interfaces, which made it incredibly difficult to write web servers for them, or to share code between two different frameworks. Now almost all Ruby web frameworks implement Rack, including Rails and Sinatra, meaning that these applications can now behave in a similar fashion to one another.

At it's core Rack provides a great set of tools to allow you to build the most simple web application or interface you can. Rack applications can be written in a single line of code. But we're getting ahead of ourselves a bit.

ryana

# Run locally
$ SPROCKETS_NON_DIGEST=true RAILS_ENV=production rake assets:precompile

# Heroku setup
$ heroku labs:enable user-env-compile
$ heroku config:add SPROCKETS_NON_DIGEST=true

be9

def paginate(scope, default_per_page = 20)
  collection = scope.page(params[:page]).per((params[:per_page] || default_per_page).to_i)

  current, total, per_page = collection.current_page, collection.num_pages, collection.limit_value

  return [{
    pagination: {
      current:  current,
      previous: (current > 1 ? (current - 1) : nil),
      next:     (current == total ? nil : (current + 1)),

jsteiner

RSpec.configure do |config|
  config.before(:suite) do
    DatabaseCleaner.clean_with(:truncation)
  end

  config.before(:each) do
    DatabaseCleaner.strategy = :transaction
  end

  config.before(:each, js: true) do

tadast

# 1) Create your private key (any password will do, we remove it below)

$ cd ~/.ssh
$ openssl genrsa -des3 -out server.orig.key 2048


# 2) Remove the password

$ openssl rsa -in server.orig.key -out server.key