Flowdock

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May 28, 2012
0 thanks

Accepted parameters for validate

Validate method also accepts :on and :if parameters. The default value for :on is :save, the other accepted values are :create and :update

class Comment
  include ActiveModel::Validations

  validate :must_be_friends, :on => :create, :if => Proc.new {|comment| some_condition}

  def must_be_friends
    errors.add(:base, "Must be friends to leave a comment") unless commenter.friend_of?(commentee)
  end
end
May 26, 2012 - (v1_9_3_125)
0 thanks

rindex with identically array elements

Code Example

a = [1,1,1]
a.rindex( a.min ) #=> 2
May 22, 2012
0 thanks

similar to clone

See the clone documentation. I see that ActiveRecord is moving from “clone” (3.0.9) to “dup” (?).

May 18, 2012
0 thanks

Beware nested with_options clobbers!

Careful:

with_options :foo => :bar do |something|
  something.with_options :foo => :baz do |inner|
    what_is(:foo)
  end
end

:foo will be :baz. It will not be [:bar, :baz], for example.

This bit me when trying to do nested with_options for validation where both had :if => something.

May 17, 2012
0 thanks

If you try to use :id as a non-primary-key field

If you’re using this so that you can repurpose :id for another use, it gets hairy: your ActiveRecord::Base subclass will still use :id to refer to your primary key, whatever it be named.

So when you call [my obj].id = 33, 33 is set as the value of your primary key, not your :id attribute!

May 17, 2012
0 thanks

Starts with capital letter alternative

Just adding an anchor to the regular expression seems simpler (and was faster in my benchmarks, not that that matters much):

'Abracadabra' =~ /^[A-Z]/
May 15, 2012
0 thanks

railz

heyyyy

May 15, 2012
0 thanks

STI - Making callbacks trigger in inherited classes

Assuming we have

class ParentClass < ActiveRecord::Base
   attr_accessible :type
end

class ChildClass < ParentClass
   after_save :perform_something
end

Executing

ParentClass.create({:type => "ChildClass"})

will not trigger ChildClass callbacks. What is more, it will return instance of ParentClass instead of ChildClass.

To resolve this issue, you need to define following module

module ActiveRecord
  module CallbacksAwareSti
    extend ActiveSupport::Concern
    module ClassMethods
      def new(*args, &block)
        return super(*args, &block) unless args.first.respond_to?(:with_indifferent_access)
        type = args.first.with_indifferent_access[:type]
        if type.blank? or (type = type.constantize) == self
          super(*args, &block)
        else
          super(*args, &block).becomes(type)
        end
      end
    end
  end
end

and include it in parent class

class ParentClass < ActiveRecord::Base
   include ActiveRecord::CallbacksAwareSti
   attr_accessible :type
end

Inspired by http://stackoverflow.com/questions/4518935/activerecord-problems-using-callbacks-and-sti

May 13, 2012
2 thanks

Undefined Method `mktmpdir' for Dir:Class

Be sure to

require 'tmpdir'

before using it. Read more at http://mikbe.tk/2011/03/07/temporary-directory.

May 10, 2012
0 thanks

block only and except

Code

class Journal < ActionController::Base
  # Require authentication for edit and delete.
  before_filter :authorize, :only => [:edit, :delete]

  # Passing options to a filter with a block.
  around_filter(:except => :index) do |controller, action_block|
    results = Profiler.run(&action_block)
    controller.response.sub! "</body>", "#{results}</body>"
  end

  private
    def authorize
      # Redirect to login unless authenticated.
    end
end
May 7, 2012
0 thanks

Hidden Field Example

Here’s a pseudo code example of a hidden field within an ERB template. A post has many comments and this comment form is in a post’s show view. This would set a comment’s post_id attribute.


<%= form_for(@comment) do |f| %>

<%= f.hidden_field :post_id, :value => @post.id %>

<% end %>


May 3, 2012
0 thanks

Starts with a Capital Letter

(or any regular expression you’d like)

'Abracadabra'[0..0] =~ /[A-Z]/       # => true
April 30, 2012 - (>= v3.1.0)
0 thanks

method to use instead

This may be obvious, but the replacement for this method is csrf_meta_tags.

April 27, 2012 - (>= v3.2.1)
1 thank

Example from Code School

module Tweets

 class ShowPresenter
   extend ActiveSupport::Memoizable

   def initialize(tweet)
     @tweet = tweet
   end

   def username
     @tweet.user.username
   end

   def status
     @tweet.status
   end

   def favorites_count
     @tweet.favorites.count
   end

   memoize :username, :status, :favorites_count

 end
end

From http://railsbest.com/

April 26, 2012 - (v1_9_3_125)
0 thanks

Dir

The documentation is using File.directory?(“/path/to/directory”), but the method being referred to is Dir.exists?().

Dir.exists?(".")
 => true

The source code is the same as File.directory?().

April 26, 2012
4 thanks
April 25, 2012 - (>= v3.1.0)
6 thanks

HTML5 data- attributes using RESTful approach

HTML5 specifies extensible attributes like data-foo=“bar” (or as in Twitter Bootstrap data-toggle=“modal”), which poses two problems for Rails.

First, if you’re using symbol notation in link_to to specify attributes, this fails (dash is not a valid symbol character), so

Invalid!

link_to "Edit", @user, :class => "btn", :data-toggle => "modal"

There are two solutions:

  1. put the symbols in quotes,

  2. use the special :data hash

Solution 1: Quote Symbols

link_to "Edit", @user, :class => "btn", "data-toggle" => "modal"

Solution 2: Use the :data hash

link_to "Edit", @user, :class => "btn", :data => {:toggle => "modal"}

Resulting HTML

<a href="/users/1" class="btn", data-toggle="modal">Edit</a>

The second is minimally documented, but as a hash, can accept multiple values and is perhaps a little cleaner

April 24, 2012 - (v1_9_3_125)
0 thanks

BasicObject.new

Instantiates a new blank object (devoid of methods). The only class method of class BasicObject. see “ri BasicObject”

eg,

> o=BasicObject.new (Object doesn’t support #inspect)

>

> o.methods NoMethodError: undefined method `methods’ for #<BasicObject:0x0000000267a0a0>

> def o.to_s > self > end

> nil

> o

> #<BasicObject:0x0000000267a0a0>

April 22, 2012
0 thanks

I got it

Perfect match to work with attr_accessible

April 19, 2012 - (v2.3.2 - v3.2.1)
0 thanks

Locale

To change default locale by the parameter you can set :locale option, like below:

select_date 'user', 'birth', :locale => 'de'
April 19, 2012 - (v3.1.0 - v3.2.1)
0 thanks

Missed close tag

At the page http://apidock.com/rails/ActionView/Helpers/TagHelper/tag

<tt>.data()</tt> should be instead of <tt>.data()<tt>

April 9, 2012
0 thanks

ferragamo

Salvatore <a href=“http://www.ferragamochaussures.com”>ferragamo pas cher, 30 ~ 70% de rabais! Salvatore ferragamo chaussures!Bienvenue à notre Salvatore ferragamo en ligne, la spécialité de vendre de Salvatore ferragamo Pas Cher style. inclure:ferragamo chaussures,ferragamo sac etc.Nous sommes à votre bon choix.site web:<a href=“http://www.ferragamochaussures.com”>http://www.ferragamochaussures.com/

April 3, 2012
1 thank

Looks like this method has trouble with attributes:

ex:

require 'rubygems'
require 'bundler'
require 'active_support/core_ext'
require 'pp'

xml  = 
  '<test id="appears">
    <comment id="doesnt appear">
      it worked
    </comment>
    <comment>
     see!
    </comment>
    <comment />
  </test>'

hash = Hash.from_xml(xml)

pp hash

#=>{"test"=>{"id"=>"appears", "comment"=>["it worked", "see!", nil]}}

# Notice how the id attribute on the first comment element doesn't appear.
April 2, 2012
1 thank

Options select_hour

In my view I wanted to do this <%= select_hour(@hour, :start => 8, :end => 12) %> but did not work. I looked at the documentation and have not seen anything like it. http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html#method-i-select_hour

So I studied how it worked this helper. http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html#method-i-select_hour develop and achieve this:

the helper application:

module DataAnnouncementsHelper

class HelperDate < ActionView::Helpers::DateTimeSelector
  def select_hour
    if @options[:use_hidden] || @options[:discard_hour]
      build_hidden(:hour, hour)
    else
      build_options_and_select(:hour, hour, :end => @options[:end], :start => @options[:start], :ampm => @options[:ampm])
    end
  end
end

def select_hour(datetime, options = {}, html_options = {})
   HelperData.new(datetime, options, html_options).select_hour
end

end

The view:

<%= select_hour(@hour, :start => 8, :end => 12) %>

Where @hour = 10 the result is:

<select id=“date_hour” name=“date[hour]”>

<option value="08">08</option>
<option value="09">09</option>
<option value="10" selected="selected">10</option>
<option value="11">11</option>
<option value="12">12</option>

</select>

March 29, 2012 - (v2.3.2 - v3.2.1)
1 thank

JQuery script for dynamically adding and removing fields_for

I like drogus idea. But I wanted a cleaner one, so I created an unobtrusive JQuery script to have the same functionality.

Example Usage:

<%= form_for @post do |form| %>
  Title: <%= form.text_field :title %>
  Body: <%= form.text_field :body %>

  Tags:
  <div id="tag-list"></div>

  <div class="numerous">
    <div class="numerous-form">
      <%= form.fields_for :tag, Tag.new, :child_index => "replace_this" do |f| %>
        <%= f.text_field :name %>
        <%= f.hidden_field :_destroy, :value => 0, :class => "numerous-remove-field" %>
        <%= link_to "delete", "#", :class => "numerous-remove" %>
      <% end %>
    </div>

    <%= link_to "add tag", "#", :class => "numerous-add", :id => "for-tag-list" %>
  </div>
<% end %>

See script at: http://github.com/kbparagua/numerous.js

March 28, 2012 - (>= v3.0.0)
0 thanks

:as option

Code

root :to => 'projects#index', :as => 'foobar'

will generate a helper

foobar_path
March 28, 2012
0 thanks

Disable layout on ajax

In actions that may or may not be loaded via ajax I use:

render :layout => !request.xhr?

For an entire controller I might use something like:

layout :has_layout?

private
  def has_layout?
    request.xhr? ? false : controller_name
  end

What seems unusual is that

layout true

will try look for the layout true.erb

March 27, 2012 - (v3.1.0 - v3.2.1)
2 thanks
March 27, 2012 - (v3.1.0 - v3.2.1)
1 thank