Masroor Hussain masroorhussainv

Controller Concerns in Rails 4

If you setup a Rails 4 app, you’ll notice the app/models/concerns and app/controllers/concerns directories. Concerns are modules that can be mixed into your models and controllers to share code between them.

Some developers falsely classify mixins as composition when they are actually a form of inheritance. When you include a module in a class, that module’s methods are added to the inheritance chain just like a parent class’ methods are added to a subclass. So, don’t think you’ve solved the problem of inheritance by simply splitting your inherited code into separate files!

That being said, mixins can be a valuable tool to share code between classes that are otherwise unrelated. Here’s an example of how I chose to use it recently.

I am adding admin reporting features to an app I’m hoping to launch soon. I have an admin controller with a simple before filter to redirect if the current user is not an administrator.

class AdminController < ApplicationController

It's important to note that running this reset will drop any existing data you have in the application

How to reset PG Database on Heroku?

Step 1: heroku restart
Step 2: heroku pg:reset DATABASE (no need to change the DATABASE)
Step 3: heroku run rake db:migrate
Step 4: heroku run rake db:seed (if you have seed)

One liner

Migration table naming convention: groups_users

Migration file naming convention (the part of the file name that is not automatically generated): create_groups_users

Model class naming convention: GroupsUser

%Q, %q, %W, %w, %x, %r, %s, %i

Perl-inspired notation to quote strings: by using % (percent character) and specifying a delimiting character.

Any single non-alpha-numeric character can be used as the delimiter, %[including these], %?or these?, %~or even these things~.

Strings

% or %Q

My notes for Dokku on Digital Ocean.

These may be a bit outdated: Since I originally wrote them, I've reinstalled on a newer Dokku and may not have updated every section below.

Commands

Install dokku-cli (gem install dokku-cli) for a more Heroku-like CLI experience (dokku config:set FOO=bar).

# List/run commands when not on Dokku server (assuming a "henroku" ~/.ssh/config alias)

ssh henroku dokku

#Goal Deploy your Rails App super easily with Dokku on Digital Ocean cheap cheap!

##Notes

Follow 12 factor design (include the rails_12factor gem)
Don't forget your Procfile with the command to start up your application server
I prefer using external hosted logging services like Logentries (not in this guide)
Set up performance monitoring AppSignal or New Relic (not in this guide)

Gemfile

gem 'simple_form'

Installation

rails generate simple_form:install

7 Patterns to Refactor Fat ActiveRecord Models

http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decompose-fat-activerecord-models/

Extract Value Objects
Extract Service Objects
Extract Form Objects
Extract Query Objects
Introduce View Objects
Extract Policy Objects

	HTTP status code symbols for Rails

	Thanks to Cody Fauser for this list of HTTP responce codes and their Ruby on Rails symbol mappings.

	Status Code Symbol
	1xx Informational
	100 :continue
	101 :switching_protocols
	102 :processing

	<%= form_for @person do \|f\| %>
	<%= f.label :first_name, "First Name" %>:
	<%= f.text_field :first_name, list: 'first-name' %>
	<datalist id="first-name">
	<% Person.all.each do \|person\| %>
	<option value="<%= person.first_name %>"></option>
	<% end %>
	</datalist>
	<%= f.submit %>
	<% end %>