published_at on Heroku/PostgreSQL

Oto_Brglez · September 26, 2011, 2:18pm

Hi all!

I have one really annoying problem - I hope you can give me some advice...

1) I have a model "Article". Article has among other fields created_at, published_at and publish_date field. I want the list of "published" articles if the publish_date is <= then current time/date.

2) In my Article model I have following scope:

github.com

otobrglez/sveze-jabolko/blob/master/app/models/article.rb#L26


      
            :if => Proc.new { |a| a.image != "" && a.image != nil }
          
          
validates_format_of :short_url,
            :with => /^(http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(:[0-9]{1,5})?(\/.*)?$/ix,
            :if => Proc.new { |a| a.short_url != "" && a.short_url != nil }  
          
          
has_many :sources
          accepts_nested_attributes_for :sources, :allow_destroy => true
          
          
default_scope order("publish_date DESC, updated_at DESC") # EX created_at
          
          
scope :published, -> {
            where(:published => 1)
            .where(:hidden => 0)
            .where("publish_date <= ?", Time.now)
          }
            
          scope :recommended, -> {
             where(:published => 1)
            .where(:recommended => 1)
            .where(:hidden => 0)

3) Settings for my timezone in rails: https://github.com/otobrglez/sveze-jabolko/blob/master/config/application.rb#L30

4) I also set TZ for my Heroku instance like so: heroku config:add TZ="Europe/Ljubljana"

5) This is my last migration: https://github.com/otobrglez/sveze-jabolko/blob/master/db/migrate/20110922105754_change_publish_date.rb

I use Heroku and PostgreSQL. But the darn thing just does not work as it should What should I do that this thing will work as expected?

I want article to be visible after the "publish_date".

Thanks for any advice and have a nice day!

- Oto

Peter_Vandenabeele1 · September 27, 2011, 8:24am

Maybe you forgot to use a block in your scope (in that case the Time.now is

evaluated only 1 time in production, at the moment the class is loaded, not at

the time the scope is called). ?

From

http://api.rubyonrails.org/classes/ActiveRecord/NamedScope/ClassMethods.html

Note that scopes defined with scope will be evaluated when they are defined, rather than when they are used. For example, the following would be incorrect:

class Post < ActiveRecord::Base

scope :recent, where(‘published_at >= ?’, Time.now - 1.week)

end

The example above would be ‘frozen’ to the Time.now value when the Post class was defined, and so the resultant SQL query would always be the same. The correct way to do this would be via a lambda, which will re-evaluate the scope each time it is called:

class Post < ActiveRecord::Base

scope :recent, lambda { where(‘published_at >= ?’, Time.now - 1.week) }

end

HTH,

Peter