Notes posted to Ruby on Rails

Compare old and new form for

Old form for

<% form_for :user, :url => users_path do %>
  <%= render :partial => 'form' %>
  <%= submit_tag 'Create' %>
<% end %>

New form for

<% form_for(@user) do |f| %>
  <%= render :partial => f %>
  <%= submit_tag 'Create' %>
<% end %>

All methods

create_table :table do |t|

  t.column # adds an ordinary column. Ex: t.column(:name, :string)
  t.index # adds a new index.
  t.timestamps
  t.change # changes the column definition. Ex: t.change(:name, :string, :limit => 80)
  t.change_default # changes the column default value.
  t.rename # changes the name of the column.
  t.references
  t.belongs_to
  t.string
  t.text
  t.integer
  t.float
  t.decimal
  t.datetime
  t.timestamp
  t.time
  t.date
  t.binary
  t.boolean
  t.remove
  t.remove_references
  t.remove_belongs_to
  t.remove_index
  t.remove_timestamps
end

All methods

change_table :table do |t|

  t.column # adds an ordinary column. Ex: t.column(:name, :string)
  t.index # adds a new index.
  t.timestamps
  t.change # changes the column definition. Ex: t.change(:name, :string, :limit => 80)
  t.change_default # changes the column default value.
  t.rename # changes the name of the column.
  t.references
  t.belongs_to
  t.string
  t.text
  t.integer
  t.float
  t.decimal
  t.datetime
  t.timestamp
  t.time
  t.date
  t.binary
  t.boolean
  t.remove
  t.remove_references
  t.remove_belongs_to
  t.remove_index
  t.remove_timestamps
end

Support for the option through

class Magazine < ActiveRecord::Base

  has_many :subscriptions
end

class Subscription < ActiveRecord::Base
  belongs_to :magazine
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :subscriptions
  has_one :magazine, :through => :subscriptions, :conditions => ['subscriptions.active = ?', true]
end

Expressions in the sum method

Person.sum(“2 * age”)

Person.sum(:age, :conditions=>'1 = 2')

Method description from Rails 2.0

If text is longer than length, text will be truncated to the length of length (defaults to 30) and the last characters will be replaced with the truncate_string (defaults to “…”).

Examples

truncate("Once upon a time in a world far far away", 14)
# => Once upon a...

truncate("Once upon a time in a world far far away")
# => Once upon a time in a world f...

truncate("And they found that many people were sleeping better.", 25, "(clipped)")
# => And they found that many (clipped)

truncate("And they found that many people were sleeping better.", 15, "... (continued)")
# => And they found... (continued)

Description copied from Rails 2.0

Extracts an excerpt from text that matches the first instance of phrase. The radius expands the excerpt on each side of the first occurrence of phrase by the number of characters defined in radius (which defaults to 100). If the excerpt radius overflows the beginning or end of the text, then the excerpt_string will be prepended/appended accordingly. If the phrase isn‘t found, nil is returned.

Examples

excerpt('This is an example', 'an', 5)
# => "...s is an examp..."

excerpt('This is an example', 'is', 5)
# => "This is an..."

excerpt('This is an example', 'is')
# => "This is an example"

excerpt('This next thing is an example', 'ex', 2)
# => "...next t..."

excerpt('This is also an example', 'an', 8, '<chop> ')
# => "<chop> is also an example"

Assert empty option in select tag

assert_tag :tag => “select”, :attributes => {:id => “to_airport_id”},

:child => {:tag => "option", :attributes => {:value => ""}, :content => "--select--"},
:children => {:count => 4}

Different Options

The docs don’t give any detail to what options are available, so I dug around and I think the only to options are :prompt and :include_blank

Test Example

UserMailerTest Example

class UserMailerTest < ActionMailer::TestCase
  tests UserMailer

  def test_welcome_mail
    user = users(:quentin)

    MyMailer.deliver_welcome_email
    assert !ActionMailer::Base.deliveries.empty?

    sent = ActionMailer::Base.deliveries.first
    assert_equal [@user.email], sent.to
    assert_equal “expected subject”, sent.subject
    assert sent.body =~ /^Welcome to my App/
    assert sent.body =~ /^Username: #{@user.login}$/
    assert sent.body =~ /^Password: [a-z0-9]{10}$/i
  end
end

This example is a modified version of the one in this blog post:

http://sablog.com/archives/2006/03/14/how-to-test-actionmailer-in-ruby-on-rails

resourceful

auto_discovery_link_tag :atom, movies_url(:format=>‘atom’), :title=>‘New movies’

to produce the feed:

respond_to do |wants|
  wants.html
  wants.atom {render :action=>'index',:layout=>false}
end

:expires_in option

If you need :expires_in functionality in Rails 2.1, you can use this plugin:

http://github.com/nickpad/rails-caches-action-patch/tree/master

unobstrusive label tag

just use

label_tag('a_a','a_a') 

and it works, just not ment for pure decorative labels :)

Turn layout off with render

Thats awkward, but the code below does not turn layout off:

render :action => "short_goal", :layout => nil

you must use false

render :action => "short_goal", :layout => false

removes underscores -> do not use for images etc

example

#does not work
label_tag('aa'+image_tag('x_x.gif')) 

print standard-looking messages during migration

Within a migration file you can use the say_with_time method to print out informational messages that match the style of standard migration messages. See the say method also.

say_with_time "migrate existing data" do
  # ... execute migration sql ...
end
#=> "-- migrate existing data"
#=> "   -> 0.0299s"

print standard-looking messages during migration

Within a migration file you can use the say method to print out informational messages that match the style of standard migration messages. The say_with_time method is also pretty great.

say "migrate existing data"
  #=> "-- migrate existing data"
# ... execute migration sql ...
say "updated all records", :subitem
  #=> "   -> updated 5 records"

:null => false

To not allow a column to have a NULL value, pass :null => false. Seems silly, but that’s it.

Strftime options

http://apidock.com/ruby/Time/strftime

Examples

Some usages:

Code example

Time.new.months_ago(1) # => Wed Aug 13 10:56:32 -0300 2008

Date.today.month_ago(7) # => Qua, 13 Fev 2008

Time.new.months_ago(1).to_s(:db) # => “2008-08-13 10:57:56”

Information on 'ModelName.transaction'

If you are looking for information about:

ModelName.transaction do
  ...
end

or

transaction do
  ...
end

see ActiveRecord::Transactions::ClassMethods

Information on 'ModelName.transaction'

If you are looking for information about:

ModelName.transaction do
  ...
end

or

transaction do
  ...
end

see ActiveRecord::Transactions::ClassMethods

CSS columns

You can also use this in a partial to create blocks of content into columns without setting a fixed height. This one is two columns.

.clear { clear: both;}
.block { float:left;width:200px;}

<div class="block">

<p>Content Item</p>

</div>
<%= cycle("", "<div class=\"clear\"></div>") -%>

Be careful with overriding dynamic attribute based finders

don’t try something like this:

class Foo < ActiveRecord::Base
  def self.find_by_bar(*args)
    foo = super(*args)
    raise SomeCustomException unless foo
    foo
  end
end

In newer versions of rails, method_missing defines find_by_bar when you first use it. By calling super, you’re triggering method_missing and overwriting your custom definition! It will work the first time then break! Manually write the call to find!

Reset a form

To reset a form easily you can do the following:

page["formid"].reset

Custom collection local variable name

Regarding the previous note from hoodow about using :variable_name to create a custom local variable name when rendering a collection with a partial, the argument should be :as instead of :variable_name, so:

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

This method has moved

To help anyone else looking, this method is now on the ActionView::Template class.

Testing protected controllers

When testing controllers which are protected with #authenticate_or_request_with_http_basic this is how you can supply the credentials for a successful login:

@request.env["HTTP_AUTHORIZATION"] = "Basic " + Base64::encode64("username:password")

Must be set before the request is sent through #get or whatever method.

Doc in ActionView::Helpers::FormHelper

See ActionView::Helpers::FormHelper’s check_box for documentation.

Creating additional cache stores

This method can be used to create additional cache stores for your application:

# creates a new Memory Store
mem_store = ActiveSupport::Cache.lookup_store
# creates a new MemCache Store
mem_cache_store = ActiveSupport::Cache.lookup_store :mem_cache_store, 'localhost:11212', :namespace => 'other_stuff'

The method takes the same arguments as the cache_store config. For more information about that go to ActionController::Caching.