Flowdock

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August 29, 2008
4 thanks

Brazilian Real (R$ 1.200,95)

helper:

def number_to_currency_br(number)
  number_to_currency(number, :unit => "R$ ", :separator => ",", :delimiter => ".")
end
August 28, 2008
8 thanks

Get year to show in descending order (Today to 1920 for example)

The way people think of time start and end would be 1920 to today. This made me think “but I want it show the current year first then down.” Well it’s as simple as swapping the start_year and end_year.

date_select :date, :start_year => Date.current.year, :end_year => 1920

# => 2008, 2007, 2006, 2005 ... 1920
August 28, 2008
3 thanks

Moved to ActiveRecord::Calculations::ClassMethods

It appears that this method has simply been moved to the module ActiveRecord::Calculations::ClassMethods. You can still use the example listed in the docs here, it will simply call the method ActiveRecord::Calculations::ClassMethods#count.

August 28, 2008 - (v2.1.0)
3 thanks

When using RESTful routes

I had issues using expire_page with RESTful controllers when expiring anything other than the index action because I was basing my expire_page calls off this example.

The solution is to use my_resource_path for example when User with id 5 is updated, you would have to do:

expire_page user_path(user) # or
expire_page formatted_user_path(user, :xml)

This may apply to early versions but I have only tested on v2.1.0

August 27, 2008
2 thanks

:variable_name

In Edge Rails you can do something like this to change the local variable name when rendering a collection:

render :partial => “video_listing”, :collection => @recommendations, :variable_name => “video”

August 27, 2008 - (v1_8_6_287)
3 thanks

Example of raising a custom exception

Create custom exception<br> <pre> class PersonalException < Exception end </pre>

Raise the exception<br> <pre> raise PersonalException.new, “message” </pre>

August 27, 2008
16 thanks

Only attr_accessible attributes will be updated

If your model specified attr_accessible attributes, only those attributes will be updated.

Use attr_accessible to prevent mass assignment (by users) of attributes that should not be editable by a user. Mass assignment is used in create and update methods of your standard controller.

For a normal user account, for example, you only want login and password to be editable by a user. It should not be possible to change the status attribute through mass assignment.

class User < ActiveRecord::Base
  attr_accessible :login, :password
end

So, doing the following will merrily return true, but will not update the status attribute.

@user.update_attributes(:status => 'active')

If you want to update the status attribute, you should assign it separately.

@user.status = 'active'
save
August 26, 2008
6 thanks

Prototype hinted_text_field application_helper

Place this in your helper. It will show a message inside the text box and remove it when someone clicks on it. If they don’t enter a value when they leave the field it’ll replace the message. (Requires javascript :defaults).

def hinted_text_field_tag(name, value = nil, hint = "Click and enter text", options={})
  value = value.nil? ? hint : value
  text_field_tag name, value, {:onclick => "if($(this).value == '#{hint}'){$(this).value = ''}", :onblur => "if($(this).value == ''){$(this).value = '#{hint}'}" }.update(options.stringify_keys)
end

# inside form_for example

hinted_text_field_tag :search, params[:search], "Enter name, brand or mfg.", :size => 30  
# => <input id="search" name="search" onblur="if($(this).value == ''){$(this).value = 'Enter name, brand or mfg.'}" onclick="if($(this).value == 'Enter name, brand or mfg.'){$(this).value = ''}" size="30" type="text" value="Enter name, brand or mfg." />
August 26, 2008
8 thanks

Customizing prompt

The :prompt option not only accepts a boolean value. It can also be given a string to define another than the standard prompt ‘Please select’. Referring to the example it could read:

collection_select(:post, :author_id, Author.find(:all),
                  :id, :name_with_initial,
                 {:prompt => 'Please select the author of this post'})
August 25, 2008 - (v1.1.6 - v2.1.0)
3 thanks

Delete collections with check box tags

Following autonomous’ directions works wonders on /edit but needs slight modifications when dealing with pagination on /index.

In a /index type listing page we can no longer assume that the list of ids coming back represents changes to all objects so we need to provide some context, that the list of object modifications in our params array is a list of modifications for some set of objects.

We can only assume subsets because pagination or filtering may reduce the set of objects we’re working on.

In our case we had a user management page which listed all users and showed whether they were activated or not. The following code is what we used to ensure that modifications to the first page of objects wouldn’t affect all the other pages.

index.rhtml

<% @users.each do |user| %>
  <%= hidden_field_tag('seen[]', user.id) -%>
  <%= check_box_tag 'activated[]', user.id -%>
<% end %>

role_controller.rb

def index
  if request.post?
    activated_ids = params[:activated].collect {|id| id.to_i} if params[:activated]
    seen_ids = params[:seen].collect {|id| id.to_i} if params[:seen]

    if activated_ids
      seen_ids.each do |id|
        r = User.find_by_id(id)
        r.activated = activated_ids.include?(id)
        r.save
      end
    end
  end
end
August 25, 2008 - (>= v2.1.0)
6 thanks

Rake tasks for gem dependencies

You can manage installation and other tasks for these dependencies with rake tasks, for example:

rake gems:install              # Installs all required gems for this application
rake gems:unpack               # Unpacks the specified gem into vendor/gems

To get all rake tasks about gems:

rake -T gems
August 25, 2008 - (v2.1.0)
4 thanks

Disable default date

If you want a date selector that initially doesn’t have a date selected you can pass it the option :include_blank.

date_select("project", "due_date", :include_blank => true)
August 25, 2008
5 thanks

%w(true false) != [true, false]

Don´t confuse the right:

validates_inclusion_of :published, :in => [true, false]

with the wrong:

validates_inclusion_of :published, :in => %w(true false)

cause:

%w(true false) == ["true", "false"]
August 23, 2008
2 thanks

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

August 23, 2008
0 thanks

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

August 23, 2008
0 thanks

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

August 23, 2008
0 thanks

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

August 23, 2008
3 thanks

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

August 23, 2008
2 thanks

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

August 23, 2008
1 thank

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

August 23, 2008
0 thanks

Adds new methods to Object and Enumerable

For using this class you need

require 'enumerator'

Which also adds this methods to Object:

  • to_enum

  • enum_for

And this other methods to Enumerable:

  • each_slice

  • enum_slice

  • each_cons

  • enum_cons

  • enum_with_index

August 23, 2008
2 thanks

Some methods listed for this class need require 'enumerator'

The methods:

need that you put this require in your scripts:

require 'enumerator'
August 23, 2008
3 thanks

Include two level has many model example

class Issue < ActiveRecord::Base

  has_many :journals
end

class Journal < ActiveRecord::Base
  belongs_to :issue
  has_many :details, :class_name => "JournalDetail", :dependent => :delete_all
end

class JournalDetail < ActiveRecord::Base
  belongs_to :journal
end

<hr/>

issue = Issue.find(:first, :include => {:journals => :details}

log record follow:

SELECT * FROM `issues` LIMIT 1
SELECT `journals`.* FROM `journals` WHERE (`journals`.`journalized_id` IN (1) and `journals`.`journalized_type` = 'Issue' AND (dustbin <> 1))
SELECT `journal_details`.* FROM `journal_details` WHERE (`journal_details`.journal_id IN (1,2,876177898,935815637))

when execute follow code, then not build sql sentent:

issue.journals
issue.journals[0].details
August 22, 2008
4 thanks

Doesn't add an index

Typically you will want to have an index on foreign keys but this method doesn’t assume that. Outside of the create_table block you should follow this with add_index :

add_index :table_name, :goat_id
# and, if polymorphic:
add_index :table_name, :goat_type
August 22, 2008
2 thanks

Response to created_at/created_on and find(:first).map

A couple of comments on the comments:

The created_at/created_on thing clearly relates to the columns that have been defined in your model – it’s got nothing to do with Rails 2.1 (although the Rails 2 “timestamp” method adds the created_at column).

And find(:first), find(:last) return model objects, rather than arrays/result sets, which is why you can’t do a map on them – you can’t do anything that you would do on an Enumerable, unless the model object itself is Enumerable.

August 22, 2008 - (>= v2.1.0)
0 thanks

This is a private method

This is not a public method, but a private class method.

>> Person.included

NoMethodError: private method `included’ called for #<Class:0x233f084>

August 22, 2008 - (>= v2.1.0)
13 thanks

Specifying :include no longer necessarily joins the association

Before Rails 2.1, adding an :include=>[:association] in your find method caused ActiveRecord to generate SQL using a join. Since 2.1, it MAY NOT execute as a join.

The join executes a large query and returned potentially duplicate records for a one-to-many association. After 2.1, the query is broken down and eager-loaded using an additional query per association, passing the set of id’s to load, and avoiding the duplicate rows.

The new method eliminates duplicates, but can incur more database overhead. If you are loading a very large set of records (more than a “page”), you may need to “force” the join or use find_by_sql instead.

When you specify a “table.column” syntax within a

:conditions=>["child.name=?", name]  

or

:order=>'child.name'

then ActiveRecord will build the older, full query with the join because you are referencing columns from another table to build. This will cause the duplicate rows to reappear.

Whenever you reference a column from another table in a condition or order clause, ALWAYS use the table name to prefix the column, even if it not ambiguous among the tables involved. Otherwise the query will not be executed as a join and you will receive an SQL error referencing the “missing” column.

You can “force” a join by adding a reference to the other tables in your :conditions or :options parameters, even if the test or sort is irrelevant.

August 21, 2008 - (v2.1.0)
0 thanks

Calling 'last' on a has_many assoication where the order is specified as a symbol raises an error.

Calling ‘last’ on a has_many assoication where the order is specified as a symbol raises an error. If you use :order, the value must be a string and not a symbol. (Prior to 2.1, :order would accept a string).

There is an incomplete Lighthouse ticket for this at http://rails.lighthouseapp.com/projects/8994/tickets/341-calling-last-on-a-has_many-assoication-where-the-order-is-specified-as-a-symbol-raises-an-error#ticket-341-1

August 20, 2008
5 thanks

Iterate and join blocks

Following LacKac’s idea, we can write render_join (useful to render a collection with a small chunks of code, where a render :partial + :spacer_template would be overkill):

def render_join(collection, join_string, &block)
  output = collection.collect do |item| 
    capture(item, &block)
  end.join(join_string)
  concat(output, block.binding)
end

An example of use:

<% render_join(@items, '<br />') do |item| %>
   <p>Item title: <%= item.title %></p>
<% end %>