1. Amazing things in Rails
@ka8725

2. Load gems precedence
config/application.rb:
config.plugins = [:devise, :i18n, :all]
* default precedence is alphabetical

3. Changing backtrace
config/initializers/backtrace_silencer.rb:
Rails.backtrace_cleaner.add_silencer { |line| line =~ /my_noisy_library/ }
Rails.backtrace_cleaner.remove_silencers!

4. List of loaded gems
$ rails c
>> $LOAD_PATH
=>[“/usr/local/lib/ruby/...”, ...]

5. Log to syslog
Allows to log to the remote server
http://docs.seattlerb.org/SyslogLogger/

6. Log to syslog
Allows to log to the remote server
http://docs.seattlerb.org/SyslogLogger/

7. Redirecting routes
config/routes.rb:
match ‘/google’, :to => redirect(‘http://google.com’)

8. Collect complicated routes
config/routes.rb:
match ‘items/list/*specs’, :controller => ‘items’, :action => ‘list’
/items/list/base/books/fiction/dickens/little_dorrit
params[:specs] # => “base/books/fiction/dickens/little_dorrit”

9. List of controller routes
$ rake routes CONTROLLER=products
Will show the list of ProductsController routes

10. Preview new record route
resources :reports do
new do
post :preview
end
end
preview_new_report POST /reports/new/preview(.:format) {:action => ‘preview’,
:controller => ‘reports’}
= form_for(report, :url => preview_new_report_path) do |f|
...
= f.submit ‘Preview’

11. Avoid member actions
resources :bids do
resource :retraction
end

12. Verify instead of before_filter
verify :params => ‘privileges’, :only => :update, :redirect_to => {:action => ‘settings’}
* Redirects to setting action unless privileges param key presents

13. Read attributes before type
casting
<attribute_name>_before_type_cast
* Example: @user.phone_before_type_cast

14. Read only attributes
class Customer < ActiveRecord::Base
attr_readonly :social_security_number
end

15. Get random record
Timesheet.limit(1).offset(rand(Timesheet.count)).first

16. Select all attributes with
calculated values
BilableWeek.select(:*, “mon_hrs + tues_hrs as two_day_total”)
* Pay attention on :*

17. Method “from” in the selects
to join tables or views
BilableWeek.select(“...”).from(“users”).where(“users.name = ‘John’”)

18. Method ‘exists?’ in AR
User.exists?(1)
User.find_by_id(1).present?

19. Use Time instead of DateTime
Time is faster because it is written in C

20. Redo migration
rake db:migrate:redo
It’s the same as:
rake db:rollback
rake db:migrate

21. Difference between << and
create on the associations
<< is transactional, but create is not
<< triggers :before_add and :after_add callbacks but create
doesn’t

22. Method ‘clear’ on the
associations
Transactionally removes all records and triggers callbacks

23. Reloading associations
User.locations(true)

24. insert_sql and delete_sql
options for associations
Convenient way to avoid callbacks
* Please, reference to rails doc

25. :autosave => true
class User < AR
has_many :timesheets, :autosave => true
end
user = User.first
user.timesheets.first.mark_for_destriction
user.save # will delete timesheet record

26. validates_acceptance_of
class Account < AR
validates_acceptance_of :privacy_policy, :terms_of_service
end
Creates virtual attributes automatically

27. validates on
class Report < AR
validates_presence_of :name, :on => :publish
end
report.valid? :publish
Validators for specific fields

28. Merging scopes
scope :tardy, :lambda {
joins(:timesheets).group(“users.id”) & Timesheet.late
}
For this purpose you are able to use merge method too

29. Callback classes
class MarkAsDeleted
def self.before_destroy(model)
model.update_attribute(:deleted_at, Time.now)
false
end
end
class Account < AR
before_destroy MarkAsDeleted
end
class Invoice < AR
before_destroy MarkAsDeleted
end

30. Callback classes
class MarkAsDeleted
def self.before_destroy(model)
model.update_attribute(:deleted_at, Time.now)
false
end
end
class Account < AR
before_destroy MarkAsDeleted
end
class Invoice < AR
before_destroy MarkAsDeleted
end

31. Calculation methods
#average
#count
#maximum
#minimum
#sum
Person.calculate(:count, :all)
Person.average(:age)
Person.minimum(:age).where(‘last_name <> ?’, ‘John’)

32. STI another column
set_inheritance_column ‘not_type’

33. Check defined local variables in
partials
local_assigns.has_key? :special

34. Entry counter in the partials
= div_for(entry) do
span ##{entry_counter}
span #{entry.name}

35. Many asset hosts
config.action_controller.asset_host = Proc.new { |source|
“http://assets#{rand(2) + 1}.example.com”
}

36. number_to_phone method
number_to_phone(1235551234) #=> “123-555-1234”

37. auto_link method
auto_link(“Go to http://google.com. Email:
test@email.com”)
=> Go to <a
href=”http://google.com”>http://google.com</a>. Email: <a
href=”mailto:test@email.com”>text@email.com</a>