Recent notes
RSS feedNeed to extend class when using this
I had to dig around to find this out - if you want to use memoize somewhere, like an ActiveRecord model, you need to add
extend ActiveSupport::Memoizable
to the class. This doesn’t seem to be explained anywhere (the only docs are 3 year old blog posts anyway).
Not available
Actually, this method is not available now.(github.com/ruby/ruby/blob/trunk/rational.c#L2352)
Difference in DateTimes ...
Mostly, the database date columns are DateTime instances. Whereas Rails adds several useful utility functions to DateTime (in activesupport), there is some confusing behavior. This is at least somewhat surprising.
Two subtract two DateTime instances, you should always “round” the returned value. Suppose:
d1 = DateTime.now d2 = d1 - 5.days.ago
then, d1 - d2 is a Rational, which tells you the difference between dates only after rounding. Thus, diff_in_days = (d1 - d2).round
This method isn't deprecated
This method was moved to AbstractController::Callbacks, as stated on [1].
It took me a while to figure out ‘what should I use instead before_filter’. Hope this helps anyone that hits the same road I’m in.
index doesn't work
@ssoroka even I’m having same issue. how did you resolve it?
Custom configuration keys
It is nice to know, that you can store any custom configuration key in configure block… E.g.
YourApp::Application.configure do # ... config.my_custom_setting = "QWERTY1234" end
Then you can just access it by calling
YourApp::Application.config.my_custom_setting
Rails 3.1 - Use request.url instead
As request.request_uri has been deprecated, use
request.url
instead.
Change in clone for ActiveRecord objects in ruby-1.9.3
I noticed that cloning an active record object in ruby-1.9.3 and then changing an attribute on the original object will actually change the cloned object as well. This was not the case in ruby-1.9.2.
Examples in a readable format :)
Here are the above examples in a somewhat more readable format:
# Assert a basic route: a controller with the default action (index) assert_routing ‘/home’, :controller => ‘home’, :action => ‘index’ # Test a route generated with a specific controller, action, and parameter (id) assert_routing ‘/entries/show/23’, :controller => ‘entries’, :action => ‘show’, :id => 23 # Assert a basic route (controller + default action), with an error message if it fails assert_routing ‘/store’, { :controller => ‘store’, :action => ‘index’ }, {}, {}, ‘Route for store index not generated properly’ # Tests a route, providing a defaults hash assert_routing ‘controller/action/9’, {:id => “9”, :item => “square”}, {:controller => “controller”, :action => “action”}, {}, {:item => “square”} # Tests a route with a HTTP method assert_routing({ :method => ‘put’, :path => ‘/product/321’ }, { :controller => “product”, :action => “update”, :id => “321” })
Wrapping with select tag
I didn’t knew how to wrap the output with <select> tag. I didn’t want to use raw html, but the doc doesn’t mention another way.
So, here is what I tried and it’s working:
<%= f.select :entry, option_groups_from_collection_for_select(@categories, :entries, :name, :id, :name) %>
I hope this helps anyone. :-)
Specify attachment names
If you want to give your attachment a name, you can do this:
attachment :filename => 'my_file.txt', :body => File.read('/var/null')
It will appear to the recipient as a file named “my_file.txt” rather than something awful like “noname 1”.
Catching and throwing -- don't!
@wiseleyb and @glosakti, neither of your suggestions are necessary, and both are bad practices.
This test:
test "transactions" do assert_raises ZeroDivisionError do User.transaction do 1/0 end end end
passes just fine on its own, with the transaction rolled back as you’d expect. No need to hack something ugly together.
logic in class/id
If you need to place some simple logic in class or like that, I think that best to make it with simple brackets:
Code example
<%= link_to ‘All actions’, switch_action_tab_path, :remote => true, :class => (‘selected’ if @tab == ‘all’) %>
unscoped.all / unscoped.count
At least in console, doing unscoped.all or unscoped.count initially returns expected results but, after you’ve added new records outside of the default_scope those two calls seem to use some cached values.
Therefore it should always be used with the block (as they sort of imply in the doc). unscoped { all } and unscoped {count }
Removed in 3.1.x
This method (and #auto_link_urls) has been removed in Rails 3.1 - other options are out there, such as Rinku, however there is a gem you can use for migration purposes etc, which is rails_autolink: http://rubygems.org/gems/rails_autolink
active_link_to helper gem
You should also have a look at github.com/twg/active_link_to if you need an ‘active’ class on your links.
Adding to the URL
If you want to use polymorphic routing for your object but you also need to specify other stuff like an anchor, you can explicitly generate the polymorphic url with extra options:
form_for @candidate, :url => polymorphic_path(@candidate, :anchor => 'signup')
Replaced by :on => :create
From rails 3,
before_validation_on_create
has been removed and replaced with:
before_validation :foo, :on => :create
Upgrading to 3.x
http://railscasts.com/episodes/202-active-record-queries-in-rails-3
Since this is deprecated, one can watch the Railcast for upgrading to 3.x
The equivalent is the ActiveRecord finder methods. http://apidock.com/rails/ActiveRecord/Fixture/find
Use Ruby instead!
E.g.
class TestClass < SomeSuperClass attr_accessor :sample_acc def initialize @sample_acc = [] super end end
If nil is not a valid value for this accessor, then you can just define reader for it.
class TestClass attr_accessor :sample_acc def sample_acc @sample_acc ||= 98 end end
Undocumented :location option
You can use undocumented :location option to override where respond_to sends if resource is valid, e.g. to redirect to products index page instead of a specific product’s page, use:
respond_with(@product, :location => products_url)
How to submit current url
For example to change some kind of param on select change…
<%= form_tag({}, {:method => :get}) do %> <%= select_tag :new_locale, options_for_select(I18n.available_locales, I18n.locale), :onchange => "this.form.submit();" %> <% end %>
Difference in the way returns are handled
Also, there is a difference in the way returns are handled from the Proc. A return from Proc.new returns from the enclosing method. Return in lambda-block acts like in regular method.
return example
def proc_return Proc.new { return "Proc.new"}.call return "proc_return method finished" end def lambda_return lambda { return "lambda" }.call return "lambda_return method finished" end puts proc_return puts lambda_return # => Proc.new # => lambda_return method finished
Unexpected rounding behavior
Both 2.5 and 1.5 are rounded to 2…
ree-1.8.7-2010.02 > sprintf("%.f", 0.5) => "0" ree-1.8.7-2010.02 > sprintf("%.f", 1.5) => "2" ree-1.8.7-2010.02 > sprintf("%.f", 2.5) => "2" ree-1.8.7-2010.02 > sprintf("%.f", 3.5) => "4" ree-1.8.7-2010.02 > sprintf("%.f", 4.5) => "4"
use round instead to get proper behavior
How to change format automatically depending on locale...
… without passing locale option.
In your application_helper.rb (or in other helper) place following code:
def number_to_currency(number, options = {}) options[:locale] ||= I18n.locale super(number, options) end
Then, in your locale files:
en-GB: number: currency: format: format: "%n %u" unit: "USD"
And that is it :)