Rails Ruby on Rails

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  siplux May 8th, 2010 @ 11:46 PM

  • Tag changed from “rails3 compatibility, datamapper, rails3” to “rails3 compatibility, activesupport, datamapper, rails3”
• 

  Dan Pickett May 9th, 2010 @ 06:36 PM

  • Tag changed from “rails3 compatibility, activesupport, datamapper, rails3” to “rails3 compatibility, activesupport, bugmash, datamapper, rails3”

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  Lawrence Pit May 11th, 2010 @ 12:09 PM

  I also have this with ActiveRecord

• 

  Neeraj Singh May 11th, 2010 @ 02:44 PM

  @lawrence Can you provide an example where you are running into same problem with ActiveRecord.

  I am able to reproduce this error with DM.

  I guess if one of the instance variables refers back to the original object as is the case with the first example provided then I see two choices.

  1) Let use pass an option :ignore_circular_reference => true. In this case in stead of raising an error, to_json method will ignore the circular reference and will move on.

  2) Let user pass an option :ignore_items => _my_intance_variable. This will provide more control to user and rather than ignoring all circular references, user is asking to_json to ignore just this variable.

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  blackgold9 May 12th, 2010 @ 06:03 AM

  I hit the same thing with my models.
  In my case, it fails if i attempt to call to_json on an activerelation object (i.e. church.where().to_json), but works if i do church.where().to_a.to_json

  my model is:

  class Church < ActiveRecord::Base
  has_many :people has_many :groups validates_presence_of :name end

  The only property it has is name.

• 

  Santiago Pastorino May 12th, 2010 @ 03:25 PM

  Can someone provide a failing test using ActiveRecord? i've tried the thing that blackgold9 said but works for me ...
  http://pastie.org/957044

• 

  Ryan Bigg May 13th, 2010 @ 11:56 PM

  • State changed from “new” to “incomplete”

  Please provide a test case and patch for this issue.

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  Bernerd Schaefer May 25th, 2010 @ 12:35 AM

  The issue here is that ActiveSupport defines Object#to_json, and therefore Post.where.to_json tries to dump the ActiveRecord::Relation object instead of passing the method call on to it's internal collection. Note, this also applies to Object#to_yaml:

  # script/rails console
  include Test::Unit::Assertions
  
  relation = Post.where # or Post.where(:author_id => 1), etc.
  
  assert_nothing_raised(ActiveSupport::JSON::Encoding::CircularReferenceError) { relation.to_json } # fails
  assert_nothing_raised(TypeError) { relation.to_yaml } # fails
  
  ActiveRecord::Relation.send(:undef_method, :to_json)
  ActiveRecord::Relation.send(:undef_method, :to_yaml)
  
  assert_equal relation.to_a.to_json, relation.to_json # and now passes
  assert_equal relation.to_a.to_yaml, relation.to_yaml # and now passes
  

  This is important because it causes the following code to generate a 500 when requesting /posts/mine.json:

  class PostsController < ApplicationController
    respond_to :html, :xml, :json
    def mine
      @posts = Posts.where(:author_id => 1)
      respond_with(@clients)
    end
  end
  

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  Marcin Kulik June 10th, 2010 @ 10:53 AM

  Requiring "json/pure" solves the problem for DataMapper, you just need to implement to_json for your models (or for DataMapper::Model).

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  Lawrence Pit June 10th, 2010 @ 12:28 PM

  What Bernerd says.. exactly the issue I have. None of my controllers work when a json request is done. You'd think this workaround would work:

     def mine
       @posts = Posts.where(:author_id => 1).all
       respond_with(@posts)
     end
  

  But that too fails in rails edge since a while, with "ArgumentError: wrong number of arguments (2 for 1)". Posts.where(:author_id => 1).to_yaml does work, Posts.where(:author_id => 1).to_json doesn't. I attempted to create a patch, but for some reason the delegation of to_json to to_a in ActiveRecord::Relation doesn't work. Anybody else have an idea?

  (see attached what I tried; I also tried what Bernerd did, undef_method of to_json, same result)

  • relation_to_json.diff 1.6 KB
• 

  Neeraj Singh June 10th, 2010 @ 04:07 PM

  • Tag changed from “rails3 compatibility, activesupport, bugmash, datamapper, rails3” to “rails3 compatibility, activesupport, bugmash, datamapper, patch, rails3”

  Attached is a patch along with test which makes it possible to have code like

  User.where(:name => 'John').to_json
  

  • 4547_fix_against_master.diff 1.4 KB
• 

  José Valim June 10th, 2010 @ 06:59 PM

  I'm not sure if we should allow Post.where(:omg).to_json. If so, what about to_xml? And to_yaml?

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  Ola Tuvesson June 22nd, 2010 @ 02:20 AM

  • Tag changed from “rails3 compatibility, activesupport, bugmash, datamapper, patch, rails3” to “json to_json, rails3 compatibility, activesupport, bugmash, datamapper, patch, rails3”

  I am having this same issue with a named scope.

  Given this model:

  class Listing < ActiveRecord::Base
    belongs_to :company
    scope :approved, lambda {
      where("approved = ?", true)
    }
  end
  

  And this controller:

  def index
    @listings = Listing.all
    @approved = Listing.approved
    ...
  end
  

  This works:

  respond_to do |format|
    format.json { render :json => @listings }
  end
  

  Whereas using the named scope fails with a CircularReferenceError:

  respond_to do |format|
    format.json { render :json => @approved }
  end
  

  Note: this is in Rails3b3

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  Dan Sully June 22nd, 2010 @ 11:22 PM

  This is still an issue with DataMapper 1.0.0 and Rails3 beta4. The above work-arounds using json/pure or dm-serializers don't work for me.

  The test script by the original poster still fails.

• 

  Neeraj Singh June 23rd, 2010 @ 03:09 PM

  • Assigned user set to “José Valim”

  Attached is patch with test.

  • 4547_fix.diff 1.7 KB
• 

  Neeraj Singh June 23rd, 2010 @ 04:56 PM

  Attached is patch with to_xml support. This patch needs be applied in addition to the patch previously mentioned.

  • to_xml_fix.diff 1.6 KB
• 

  Repository June 23rd, 2010 @ 05:17 PM

  • State changed from “incomplete” to “resolved”

  (from [eb04408a20628a49296e0859425940b39a83ec63]) ActiveRecord's relation object should respond to to_json and to_yaml

  [#4547 state:resolved]

  Signed-off-by: José Valim jose.valim@gmail.com
  http://github.com/rails/rails/commit/eb04408a20628a49296e0859425940...

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  Marcin Kulik June 23rd, 2010 @ 07:20 PM

  How above ActiveRecord patch is supposed to solve serializing DataMapper objects??

• 

  José Valim June 23rd, 2010 @ 07:25 PM

  • State changed from “resolved” to “open”

  Hahahaha! The patch was not supposed to close this issue, it just solves another issue raise in this same thread. Reopening.

• 

  José Valim June 26th, 2010 @ 10:49 AM

  • State changed from “open” to “invalid”
  • Importance changed from “” to “Low”

  About Datamapper: you need to define a as_json implementation for your models, otherwise Rails will use the default implementation causing the errors you mentioned. Maybe, dm-rails guys, could include a default as_json implementation. But I cannot see anything Rails could do here.