Charles FD freiden

Building Rich Domain Models in Rails

Abstract

Domain model is an effective tool for software development. It can be used to express really complex business logic, and to verify and validate the understanding of the domain among stakeholders. Building rich domain models in Rails is hard. Primarily, because of Active Record, which doesn't play well with the domain model approach.

One way to deal with this problem is to use an ORM implementing the data mapper pattern. Unfortunately, there is no production ready ORM doing that for Ruby. DataMapper 2 is going to be the first one.

Another way is to use Active Record just as a persistence mechanism and build a rich domain model on top of it. That's what I'm going to talk about here.

Building Rich Domain Models in Rails.

Part 1. Decoupling Persistence.

Abstract

Domain model is an effective tool for software development. It can be used to express really complex business logic, and to verify and validate the understanding of the domain among stakeholders. Building rich domain models in Rails is hard. Primarily, because of Active Record, which doesn't play well with the domain model approach.

One way to deal with this problem is to use an ORM implementing the data mapper pattern. Unfortunately, there is no production ready ORM doing that for Ruby. DataMapper 2 is going to be the first one.

Another way is to use Active Record just as a persistence mechanism and build a rich domain model on top of it. That's what I'm going to talk about in this article.

I'm hunting for the best solution on how to handle keeping large sets of DB records "sorted" in a performant manner.

Problem Description

Most of us have work on projects at some point where we have needed to have ordered lists of objects. Whether it be a to-do list sorted by priority, or a list of documents that a user can sort in whatever order they want.

A traditional approach for this on a Rails project is to use something like the acts_as_list gem, or something similar. These systems typically add some sort of "postion" or "sort order" column to each record, which is then used when querying out the records in a traditional order by position SQL query.

This approach seems to work fine for smaller datasets, but can be hard to manage on large data sets with hundreds (or thousands) of records needing to be sorted. Changing the sort position of even a single object will require updating every single record in the database that is in the same sort group. This requires potentially thousands of wri

ruby-1.9.3-p484 cumulative performance patch for rbenv

This installs a patched ruby 1.9.3-p484 with the railsexpress patchsets: https://github.com/skaes/rvm-patchsets

Requirements

You will also need a C Compiler. If you're on Linux, you probably already have one or know how to install one. On OS X, you should install XCode, and brew install autoconf using homebrew.

How to purge ('ban') an entire domain in Varnish Cache 3

#####EDIT: NB Ban is technically different from Purge. Banned objects remain in memory but banning is faster than purging. Read the Varnish 3 documentation here and here.

Purge may be a more appropriate action for your use-case; although the examples in the gist below work, it's not necessarily the best way of doing this.

How to set up stress-free SSL on an OS X development machine

One of the best ways to reduce complexity (read: stress) in web development is to minimize the differences between your development and production environments. After being frustrated by attempts to unify the approach to SSL on my local machine and in production, I searched for a workflow that would make the protocol invisible to me between all environments.

Most workflows make the following compromises:

Use HTTPS in production but HTTP locally. This is annoying because it makes the environments inconsistent, and the protocol choices leak up into the stack. For example, your web application needs to understand the underlying protocol when using the secure flag for cookies. If you don't get this right, your HTTP development server won't be able to read the cookies it writes, or worse, your HTTPS production server could pass sensitive cookies over an insecure connection.
Use production SSL certificates locally. This is annoying

	<?php
	array(
	array('id' => 1, 'title' => _('Afghane')),
	array('id' => 2, 'title' => _('Albanaise')),
	array('id' => 3, 'title' => _('Algerienne')),
	array('id' => 4, 'title' => _('Allemande')),
	array('id' => 5, 'title' => _('Americaine')),
	array('id' => 6, 'title' => _('Andorrane')),
	array('id' => 7, 'title' => _('Angolaise')),
	array('id' => 8, 'title' => _('Antiguaise et barbudienne')),

	class RouteRecognizer
	attr_reader :paths

	# To use this inside your app, call:
	# `RouteRecognizer.new.initial_path_segments`
	# This returns an array, e.g.: ['assets','blog','team','faq','users']

	INITIAL_SEGMENT_REGEX = %r{^\/([^\/\(:]+)}

	def initialize

	// Support routines for automatically reporting user timing for common analytics platforms
	// Currently supports Google Analytics, Boomerang and SOASTA mPulse
	// In the case of boomerang, you will need to map the event names you want reported
	// to timer names (for mPulse these need to be custom0, custom1, etc) using a global variable:
	// rumMapping = {'aft': 'custom0'};
	(function() {
	var wtt = function(n, t, b) {
	t = Math.round(t);
	if (t >= 0 && t < 3600000) {
	// Google Analytics

	# spec/support/capybara/select2_helper.rb or features/support/select2_helper.rb

	module Select2Helper
	# @example
	# select2 "Item", from: "select_id"
	# select2 /^Item/, from: "select_id"
	#
	# @note Works with Select2 version 3.4.1.
	def select2(text, options)
	find("#s2id_#{options[:from]}").click