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September 10, 2012
0 thanks

__callee__ and __method__ both return symbol when originally defined, not current

There has been some indication that __callee__ is intended to return the symbol with which the method was actually invoked, whereas __method__ returns name with which the method was originally defined, but __callee__ actually behaves identically to __method__ in Ruby 1.9.1 1.9.2, and 1.9.3.

This distinction is meaningful, because methods can be aliased after they are created.

In Ruby 1.8.7, it was possible (though) not convenient to get the name of the method as actually invoked, by calling another method that extracts the name from caller.first. Even that hack no longer works in Ruby 1.9 though, since it will return the originally defined method name as well.

September 5, 2012 - (v3.2.1 - v3.2.8)
1 thank

ActiveModel::MassAssignmentSecurity::Error

Note that in the example shown in the documentation, `user.assign_attributes({ :name => ‘Josh’, :is_admin => true })` would raise a `ActiveModel::MassAssignmentSecurity::Error` and would not actually update user.name, contrary to what the example seems to demonstrate.

September 5, 2012 - (>= v3.0.0)
0 thanks

Don't allow mass assignments on model

To block all mass assignments on a model, it’s as simple as having an empty list of accessible attributes.

example
class Users < ActiveRecord::Base
   attr_accessible #none
end
August 30, 2012
2 thanks

Usage

In Rails 3.X console:

Rails.application.routes.recognize_path('/my_path')
August 30, 2012
0 thanks

How to handle dynamic controller class evaluation based on params

Possible with following snippet of code (for instance if each branch has some different controller logic, but if the controller is not present, it should fallback to default controller).

Advantages are so we do not have to make blank inherited controllers and routes for them, to do it with plain inheritance.

class ActionDispatch::Routing::RouteSet::CustomDispatcher < ActionDispatch::Routing::RouteSet::Dispatcher
  # These are the controllers that we should attempt fallbacks on
  FALLBACK_CONTROLLERS = /customer\/branch\/(projects|events)$/

  def controller(params, default_controller=true)
    # This defines when we want to attempt fallbacks pattern
    super unless params[:branch_id] && params[:controller].try(:match, FALLBACK_CONTROLLERS)
    controller_param = params[:controller]

    # Having these supplied, we handle controller evaluation by our own method...
    controller_reference_with_fallbacks(params[:branch_id], controller_param)
  rescue NameError => e
    raise ActionController::RoutingError, e.message, e.backtrace if default_controller
  end

  private

  def controller_reference_with_fallbacks(branch_id, controller_param)
    # This is how fallbacks are evaluated       
    controller_name = "#{controller_param.sub('/branch', "/branch/#{branch_id}").camelize}Controller"

    controller = ActiveSupport::Dependencies.reference(controller_name)

    begin
      controller.get(controller_name)
    rescue NameError => e  # If there is no specific class for given branch, fallback to original class
      controller_reference(controller_param)
    end
  end
end

ActionDispatch::Routing::Mapper::Mapping.class_eval do
  private

  # We do overwrite dispatcher class, that is used to evaluate controller classes from params
  def app
    ActionDispatch::Routing::Mapper::Constraints.new(
        to.respond_to?(:call) ? to : ::ActionDispatch::Routing::RouteSet::CustomDispatcher.new(:defaults => defaults),
        blocks,
        @set.request_class
    )
  end
end
August 24, 2012
0 thanks

Specify :host option in emails

Emails need a fully qualified URL (with domain). Use the :host parameter.

But note also that you need to specify a value that is not dependent upon the request context. http://api.rubyonrails.org/classes/ActionMailer/Base.html recommends setting a default host in application.rb For those of us who have development, test, staging and production environments, set in the environment-specific files, or in the :default hash in the mailer.

This applies to both +url_for(:host => “example.com”)+ and when using named routes as in +widgets_url(:host => “example.com”)+

August 22, 2012 - (>= v3.0.0)
0 thanks

Rails Guides

There is an excellent guide on the use of this method located here:

http://guides.rubyonrails.org/active_record_querying.html#conditions

August 22, 2012 - (v3.2.8)
0 thanks

Using Amazon Simple Email Service with ActionMailer

First of all, get all the necessary SES credentials and verify your email address.

Then, just edit your config/environments/*.rb files:

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
    address: 'email-smtp.us-east-1.amazonaws.com',
    user_name: 'your-ses-smtp-user-name',
    password: 'your-ses-smtp-password',
    authentication: :login,
    enable_starttls_auto: true
}

And that’s it!

August 22, 2012
0 thanks

in rails3 StatusCodes have been moved to Rack::Utils

in rails3 StatusCodes have been moved to Rack::Utils

August 20, 2012
0 thanks

To use class attribute with a hash

You can use a setter with merge:

self.settings = settings.merge(key => value)
August 19, 2012
0 thanks

On destroying data

Reply to tvle83 and pgmcgee: the destructiveness of this method depends on your database. Some databases are better at converting between disparate types than others. For example, when changing a column from a numeric type to a string type, some databases drop the data where others will turn the numbers into their string representations.

Essentially, YMMV.

August 6, 2012
0 thanks

What it do?

For those favoring YAML outputs, this methods simply and recursively outputs the keys and values in YAML (into a String) for your pleasure.

August 3, 2012
0 thanks

a misprint?

In section ‘Bi-directional associations’ an example:

d = Dungeon.first

t = d.traps.first

d.level == t.dungeon.level # => true

d.level = 10

d.level == t.dungeon.level # => false

Then use has_many associations, but lower than written ‘for belongs_to associations has_many inverse associations are ignored.’

July 24, 2012
1 thank

rest of code is in Object#try

The logic for #try is shared between this method and Object#try – “Show source” here doesn’t show the whole story. Both methods are currently implemented in the file activesupport/lib/active_support/core_ext/object/try.rb .

July 24, 2012
2 thanks

rest of code is in NilClass#try

If you click “Show source” here, you may get confused. The logic for #try is shared between this method and NilClass#try . Both versions are currently implemented in the file activesupport/lib/active_support/core_ext/object/try.rb .

July 23, 2012
2 thanks

Long-wanted functional extension

This is pretty nice method allowing you to build stuff in a functional way.

Lets say you want to build a hash from an array, keyed by array object, where each value is the number of same objects in the array.

# imperative style :-P

h = Hash.new(0)
[1, 3, 2, 3, 1, 3].each { |i| h[i] += 1 }
h # => {1=>2, 3=>3, 2=>1} 

# functional style, using inject. Note that you need to explicitly return the accumulator in the end

[1, 3, 2, 3, 1, 3].inject(Hash.new(0)) { |a, i| a[i] += 1; a } 
# => {1=>2, 3=>3, 2=>1} 

# using each_with_object. Note the reversed block params - accumulator is the last parameter. 
# Mnemonic: consistent with each_with_index, where object is the first parameter

[1, 3, 2, 3, 1, 3].each_with_object(Hash.new(0)) {|i, a| a[i] += 1}
# => {1=>2, 3=>3, 2=>1} 
July 23, 2012
0 thanks

Replacement

Replacement

# Method using returning can replaced
def foo
  returning Hash.new do |h|
    h[:foo] = "bar"
  end
end
# By method using tap  
def foo
  Hash.new.tap do |h|
    h[:foo] = "bar"
  end
end
July 20, 2012
1 thank

Skipping validation - follow up

For Rails 2.x use #save(false) for Rails 3.x use #save(:validate => false)

July 20, 2012
0 thanks

Set ids when using a collection of values (cont.)

Regarding schmidt’s post.

The following will not have the expected behavior:

<% Car.each do |c| %>
  <%= check_box_tag "car_ids[]", c.id, :id => "car_ids_#{c.id}" %>
<% end %>

But, if you put the “checked” option to false (or true), it will.

<% Car.each do |c| %>
  <%= check_box_tag "car_ids[]", c.id, false, :id => "car_ids_#{c.id}" %>
<% end %>
July 20, 2012 - (v3.0.0 - v3.2.3)
2 thanks

Changing the Message

For Change the default message:

Code example

validates :invoice_number, :presence => {:message => 'The invoice number must be informed.'}
July 19, 2012
0 thanks

Assignment using 'key: value'

Another shorthand way of assigning key, value pairs:

Hash[one: 1, two: 2] #=> {:one=>1, :two=>2}
July 12, 2012
1 thank

conditional rescue_from

Would it be possible to do something like:

rescue_from Exception, :with => my_handler, :unless => request.local?
July 10, 2012
0 thanks

Checking content_for

@tordans You asked your question 3 years ago, but in any case, should anyone have that same issue, you can manage that with:

- unless content_for(:footer).blank?
  yield(:footer)
- else
  == render "layouts/footer_big"

content_for(:x) defaults to an empty string, that’s why you need to check for blank? not nil?.

July 9, 2012
0 thanks

this has been deprecated; replace with Memoist

In Rails 3.2, memoize has been deprecated. In edge Rails, it has been removed.

The commit when it was deprecated: http://github.com/rails/rails/commit/36253916b0b788d6ded56669d37c96ed05c92c5c

A Stack Overflow question about this change: http://stackoverflow.com/q/9132197/578288

I personally disagree with the removal of memoize, and don’t recommend using the `||=` pattern Rails now suggests. The exception is if your entire program only memoizes something once or twice, so it’s not worth including a gem for.

The easiest way to keep using memoize is to use the Memoist gem (http://github.com/matthewrudy/memoist , http://rubygems.org/gems/memoist), which is a simple extraction of ActiveSupport::Memoizable into its own gem.

June 28, 2012
0 thanks

see also – similar methods

See also DateTime#strftime and Date#strftime . (They work similarly, but have different APIdock notes.)

June 28, 2012
0 thanks

see also – similar methods

See also Time#strftime and DateTime#strftime . (They work similarly, but have different APIdock notes.)

June 28, 2012
0 thanks

see also – similar methods

See also Time#strftime and Date#strftime . (They work similarly, but have different APIdock notes.)

June 25, 2012 - (<= v2.3.8)
0 thanks

Adding Additional Parameters to form_for

If you want to add additional parameters to the form_for helper, but still want to use one form for both your “create” and your “update” actions, you can add the additional parameters to the :url option, but you need to omit the :controller and :action keys.

form_for(@user, :url => {:param1 => "value1", :param2 => "value2"}) do |f|

or

form_for([@post, @comment], :url => {:param1 => "value1", :param2 => "value2"}) do |f| 

where param1 and param2 are not :controller or :action

June 22, 2012 - (v1_8_6_287 - v1_9_3_125)
2 thanks

Test if an array is included in another

Array

class Array
   def included_in? array
     array.to_set.superset?(self.to_set)
   end
end

[1,2,4].included_in?([1,10,2,34,4]) #=> true