1. NoMethodError
Monday, June 10, 13

2. SUBLIMETEXT MULTIPLE
CURSORS
• CMD+left
• Alt+left
• selection
•Copy/Paste
• CMD+d
•Ctrl+CMD+g
Monday, June 10, 13

3. GIT REFLOG AKA UNDO ANYTHING
SHIT!
Monday, June 10, 13

4. ‘DEBUGGING’ STUFF
WITHOUT DOCS
export BUNDLER_EDITOR=subl
bundle open rails
use Sublime Find in files
Tudi varianta:
git clone ....
Gemfile:
gem :devise, path:‘/home/user/stuff/devise’
Monday, June 10, 13

5. rake db:create db:migrate db:seed
or use Zeus and don’t care
Monday, June 10, 13

6. MEMOIZATIONTRICKS
def data
@data ||= begin
data = fetch_data("http://www.com")
JSON.load(data)
rescue Errno::ECONNREFUSED
{ error: 'Connection refused.' }
end
end
###
def data
@data = get_data unless instance_variable_defined?(:@data)
end
def get_data
# ...
rescue
# ...
end
Monday, June 10, 13

7. rails g model Fart ass:references
rails g model Fart ass:belongs_to
automatically adds index
automatically puts belongs_to into model
class CreateFarts < ActiveRecord::Migration
def change
create_table :farts do |t|
t.references :ass, index: true
t.belongs_to :ass, index: true
t.timestamps
end
end
end
class Fart < ActiveRecord::Base
belongs_to :ass
end
Monday, June 10, 13

8. RUBY INSTRUCTION
SEQUENCE
Monday, June 10, 13

9. PRESENT?
def show
@user = User.find(params[:id])
if @user.present?
# ...
end
end
def show
@user = User.find(params[:id])
if @user
# ...
end
end
STOP ABUSING!
Monday, June 10, 13

10. PRESENCE
"".presence # => nil
"X".presence # => "X"
[].presence # => nil
[1].presence # => [1]
Monday, June 10, 13

11. ACCEPTS_NESTED_ATTRIBUTES_FOR
bundle open rails
implement custom version in our app
Monday, June 10, 13

12. ADD METHODS WITH SCOPE
class Fart < ActiveRecord::Base
scope :page, ->(page = 1) { where(page: page) } do
def per(per = 10)
limit(per)
end
end
end
Fart.per(20)
# NoMethodError: undefined method `per'
Fart.page(2).per(20).to_sql
# => "SELECT "farts".* FROM "farts" WHERE "farts"."page" = 2
LIMIT 20"
Kaminari does this: .page(...) adds .per(...)
Monday, June 10, 13

13. GROUP COUNT
# Useless:
Fart.group(:ass_id).count # => { 1 => 1, 2 => 1 }
# Slow:
Fart.group(:ass_id).count.keys.count # => 2
# Fast + should work for any query:
scope = Fart.group(:ass_id).select("1")
query = "SELECT count(*) AS count_all FROM (#{scope.to_sql}) x"
ActiveRecord::Base.connection.execute(query)["count_all"].to_i # => 2
# Gem: mrbrdo/active_record_group_count
Fart.group(:ass_id).returns_count_sum.count # => 2
# Works with Kaminari
Fart.group(:ass_id).returns_count_sum.page(1).per(10)
Monday, June 10, 13

14. RAILS 3 ASSIGN_ATTRIBUTES
WITHOUT PROTECTION
PS: use strong_parameters (even in Rails 3), attr_accessible sucks
Fart.new(name: 'lol') # ActiveModel::MassAssignmentSecurity::Error
fart = Fart.new({ name: 'lol' }, without_protection: true)
fart.update_attributes({ name: 'lol' }, without_protection: true)
fart.assign_attributes({ name: 'lol' }, without_protection: true)
be careful
Monday, June 10, 13

15. RAILS CONSOLE SANDBOX
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16. Monday, June 10, 13