Error creating model object using accepts_nested_attributes_for

rubyonrails-talk
1

Folks,

I am on Rails 2.3.8. I have models declared as below

class GradeSection < ActiveRecord::Base   has_many :class_calendars   <more stuff> end

class ClassCalendar < ActiveRecord::Base   has_many :uploaded_attachments, :class_name => 'UploadedAttachment'   accepts_nested_attributes_for :uploaded_attachments   belongs_to :grade_section end

class UploadedAttachment < ActiveRecord::Base   belongs_to :class_calendar   has_attached_file :phile,         :url => "/assets/class_cal/:id/:style/:basename.:extension" end

In my create function in GradeSection controller I get data posted as such

Processing GradeSectionController#create (for 127.0.0.1 at 2010-11-27 22:13:46) [POST]   Parameters: {"authenticity_token"=>"fwdgGanIsScNQUcm6sYc952xhT2BSVH6LXggOJdxhKo=", "class_calendar"=>{"dt"=>"Mon Dec 13 2010 22:13:35 GMT-0800 (Paci fic Standard Time)", "summary"=>"", "grade_section_id"=>"1", "chkproj"=>"0", "uploaded_attachments"=>{"name"=>"Test 2"}, "chkhw"=>"1"}}

"name" is a string field for filename in UploadedAttachments model (I am going to use that model for storing uploaded attachments but taking incremental steps - getting just the name for now) and grade_section_id is passed in so I create the model through ClassCalendar

When I get the above posted data, in the create function of GradeSectionController, I create a ClassCalendar object from params that are submitted as below

@cc = ClassCalendar.new(params[:class_calendar]) # line 96 in the code

But this line gives me the following error

#================= Error Message ======================= ActiveRecord::AssociationTypeMismatch (UploadedAttachment(#90313070) expected, got Array(#1200170)):   app/controllers/grade_section_controller.rb:96:in `new'   app/controllers/grade_section_controller.rb:96:in `create'   c:/ruby/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/lib/ruby- debug.rb:101:in `debug_load'   c:/ruby/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/lib/ruby- debug.rb:101:in `debug_program'   c:/ruby/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/bin/rdebug-ide: 82   c:\ruby\bin\rdebug-ide:19:in `load'   c:\ruby\bin\rdebug-ide:19   -e:2:in `load'   -e:2 #================= end error message =======================

I may be missing something very simple but I don't understand the error and don't quite know how to debug this - getting an Array instead of UploadedAttachment. Looking for help with any pointers on what the issue is and how to debug such errors.

Thanks, -S

2

Looking for any pointer to help address or some way to debug this problem. Appreciate any thoughts.

Thanks, -S

3

Folks,

I am on Rails 2.3.8. I have models declared as below

class GradeSection < ActiveRecord::Base has_many :class_calendars <more stuff> end

class ClassCalendar < ActiveRecord::Base has_many :uploaded_attachments, :class_name => 'UploadedAttachment' accepts_nested_attributes_for :uploaded_attachments belongs_to :grade_section end

class UploadedAttachment < ActiveRecord::Base belongs_to :class_calendar has_attached_file :phile, :url => "/assets/class_cal/:id/:style/:basename.:extension" end

In my create function in GradeSection controller I get data posted as such

Processing GradeSectionController#create (for 127.0.0.1 at 2010-11-27 22:13:46) [POST] Parameters: {"authenticity_token"=>"fwdgGanIsScNQUcm6sYc952xhT2BSVH6LXggOJdxhKo=", "class_calendar"=>{"dt"=>"Mon Dec 13 2010 22:13:35 GMT-0800 (Paci fic Standard Time)", "summary"=>"", "grade_section_id"=>"1", "chkproj"=>"0", "uploaded_attachments"=>{"name"=>"Test 2"},

Since no one else has responded, and I don't know how it relates to the error you are seeing, but I wonder whether this should be an array of uploaded_attachments rather than a single instance.

Whether that is the issue or not, it might be worth removing the attachements spec from the form initially just to check that you can create a new object without the nested objects.

"chkhw"=>"1"}}

"name" is a string field for filename in UploadedAttachments model (I am going to use that model for storing uploaded attachments but taking incremental steps - getting just the name for now) and grade_section_id is passed in so I create the model through ClassCalendar

When I get the above posted data, in the create function of GradeSectionController, I create a ClassCalendar object from params that are submitted as below

@cc = ClassCalendar.new(params[:class_calendar]) # line 96 in the code

But this line gives me the following error

#================= Error Message ======================= ActiveRecord::AssociationTypeMismatch (UploadedAttachment(#90313070) expected, got Array(#1200170)): app/controllers/grade_section_controller.rb:96:in `new' app/controllers/grade_section_controller.rb:96:in `create' c:/ruby/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/lib/ruby- debug.rb:101:in `debug_load' c:/ruby/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/lib/ruby- debug.rb:101:in `debug_program' c:/ruby/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/bin/rdebug-ide: 82 c:\ruby\bin\rdebug-ide:19:in `load' c:\ruby\bin\rdebug-ide:19 -e:2:in `load' -e:2 #================= end error message =======================

I may be missing something very simple but I don't understand the error and don't quite know how to debug this - getting an Array instead of UploadedAttachment. Looking for help with any pointers on what the issue is and how to debug such errors.

Do you know how to use reby-debug to break into your code and inspect data and follow flow. You could break in before the offending line to double check the data at that point. See the Rails Guide on debugging if you are not familiar with this.

Colin

4

This data doesn't look like what the nested_attributes stuff looks like - I would expected it to be more like 'uploaded_attachments_attributes' => {{'0' => {'name' => 'Test 2'}}

What does your form look like?

Fred

5

Thanks Frank. I finally found this post on the forum Problems with accepts_nested_attributes_for - Rails - Ruby-Forum that points out what you have. It is interesting that the form_for declaration in the view has to be something like follows

<% form_for @modelname do |f| %>

instead of

<% form_for :modelname do |f| %>

Don't yet understand why this makes a difference but that is what makes the difference and posts data with nested model name appended with "attributes" as you point below.

Thanks for the feedback - very much appreciated. Past that hurdle and onto the next one.

-S

Frederick Cheung wrote in post #965073: