Help with nested models and fields_for

Hi folks.

I'm trying to do stuff with models nested one layer deeper than I've done in the past...and it's just not working properly. Here's the situation:

* I have three models involved here: Recipe, IngredientLine, and Ingredient (it's a cookbook application).

class Recipe < ActiveRecord::Base   has_many :ingredient_lines   has_many :ingredients, :through => :ingredient_lines end

class IngredientLine < ActiveRecord::Base   belongs_to :ingredient   belongs_to :recipe end

class Ingredient < ActiveRecord::Base   has_many :ingredient_lines   has_many :recipes, :through => :ingredient_lines end

* I'm trying to develop a form which edits a Recipe along with its associated IngredientLines and Ingredients. Right now, I've been working with this sort of thing (it's a Facebook app, hence the .fbml extension, and I'm only doing relevant excerpts so as not to take up too much space here):

--- recipe/views/new.fbml.haml ---

- form_for(@current_object) do |f|   = f.text_field :name   = render :partial => 'ingredient', :locals => {:f => f}   = f.text_area :instructions

--- recipe/views/_ingredient.fbml.haml --- - f.fields_for :ingredient_lines, :index => nil do |ff|   %td= ff.text_field :quantity, :size => 3, :maxlength => 3, :id => nil   %td= ff.text_field :unit, :id => nil   - ff.fields_for :ingredient do |i|     %td= i.text_field :name, :id => nil

* I've tried this with fields_for instead of f.fields_for as well.

* There's some JavaScript to produce multiple copies of the partial for multiple ingredient, but I'm omitting that since it's not relevant here.

* The HTML/FBML output for this is as expected:

<form action="/recipes" class="new_recipe" id="recipe_1015" method="post">   <input id="recipe_name" name="recipe[name]" size="30" type="text" />   <input id="recipe_ingredient_lines__quantity" maxlength="3" name="recipe[ingredient_lines][quantity]" size="3" type="text" />   <input id="recipe_ingredient_lines__unit" name="recipe [ingredient_lines][unit]" size="30" type="text" />   <input id="recipe_ingredient_lines__ingredient_name" name="recipe [ingredient_lines][ingredient][name]" size="30" type="text" />   <textarea cols="40" id="recipe_instructions" name="recipe [instructions]" rows="20"></textarea> </form>

So far so good. But here's the problem: *submissions don't work quite properly*. When I fill out the form and submit it, I get params entries like "recipe"=>{"name"=>"Recipe", "ingredient_lines"=>[{"quantity"=>"1", "unit"=>"cup", "ingredient"=>{}}], "instructions"=>"Preheat oven to 350°..."}. Note that ingredient_lines[0].ingredient.name is missing, even if I enter text in the corresponding form field -- in other words, what I should be seeing is something like "recipe"=> {"name"=>"Recipe", "ingredient_lines"=>[{"quantity"=>"1", "unit"=>"cup", "ingredient"=>{"name" => "flour"}}], "instructions"=>"Preheat oven to 350°..."}. What am I doing wrong?

Any suggestions would be helpful. Thanks in advance!

Best,

Marnen Laibow-Koser wrote:

  <input id="recipe_ingredient_lines__ingredient_name" name="recipe [ingredient_lines][ingredient][name]" size="30" type="text" />

So far so good. But here's the problem: *submissions don't work quite properly*. When I fill out the form and submit it, I get params entries like "recipe"=>{"name"=>"Recipe", "ingredient_lines"=>[{"quantity"=>"1", "unit"=>"cup", "ingredient"=>{}}], "instructions"=>"Preheat oven to 350°..."}. Note that ingredient_lines[0].ingredient.name is missing, even if I enter text in the corresponding form field -- in other words, what I should be seeing is something like "recipe"=> {"name"=>"Recipe", "ingredient_lines"=>[{"quantity"=>"1", "unit"=>"cup", "ingredient"=>{"name" => "flour"}}], "instructions"=>"Preheat oven to 350°..."}.

I believe this is a limitation of Rails' parameter parsing. It can't handle more that one level below an array parameter.

A solution is to create an ingredient_name accessor in IngredientLine, and arrange to have this rendered and posted.

I believe this is a limitation of Rails' parameter parsing.

I was afraid of that. This may be the excuse I need to start hacking the core. :slight_smile:

It can't handle more that one level below an array parameter.

Are you sure? I've seen a few examples on the Web which imply that this should work.

By "array parameter", do you specifically mean one with a numeric subscript, so that object[foo][bar][baz] would work as expected, although objects[foo][bar][baz] would not? If so, that would explain some -- not all -- of the examples I've seen.

A solution is to create an ingredient_name accessor in IngredientLine, and arrange to have this rendered and posted.

Yeah, but that's so *ugly*...

Best,

Marnen Laibow-Koser wrote:

It can't handle more that one level below an array parameter.

Are you sure? I've seen a few examples on the Web which imply that this should work.

I can confirm that it's broken in Rails 2.0.2, and fixed in Rails >= 2.1.0.

By "array parameter", do you specifically mean one with a numeric subscript, so that object[foo][bar][baz] would work as expected, although objects[foo][bar][baz] would not? If so, that would explain some -- not all -- of the examples I've seen.

objects[foo] works, but objects[foo][bar] did not.

Marnen Laibow-Koser wrote: >> It can't handle more that one level below an array parameter.

> Are you sure? I've seen a few examples on the Web which imply that > this should work.

I can confirm that it's broken in Rails 2.0.2, and fixed in Rails >= 2.1.0.

Then something else is going on. I'm using Rails 2.2.2 and having these problems.

[...]

objects[foo] works, but objects[foo][bar] did not.

And still apparently does not. Any other thoughts?

Best,

Marnen Laibow-Koser wrote:

Marnen Laibow-Koser wrote:

It can't handle more that one level below an array parameter.

Are you sure? I've seen a few examples on the Web which imply that this should work.

I can confirm that it's broken in Rails 2.0.2, and fixed in Rails >= 2.1.0.

Then something else is going on. I'm using Rails 2.2.2 and having these problems.

[...]

objects[foo] works, but objects[foo][bar] did not.

And still apparently does not. Any other thoughts?

The test I did was to post from the following view.

<form> <input name="recipe[ingredient_lines][ingredient][name]" type="text"/> </form>

On Rails >= 2.1 I got the correct "recipe"=>{"ingredient_lines"=>[{"ingredient"=>{"name"=>"hhh"}}]}

on 2.0.2 I got what you're seeing: "recipe"=>{"ingredient_lines"=>[{"ingredient"=>{}}]}

You may like to run the same test.

If you see the same, perhaps the problem manifests when extra parameters are added. You can try adding fields until you are posting your complete form. Please post what you find out.

Thanks for the suggestion. I tried the same test, and got interesting if disheartening results. When I had recipe[ingredient_lines] [ingredient][name] as the only form field, I got the same results as you. But the moment I added recipe[ingredient_lines][unit], [ingredient][name] stopped working. This was true both with Rails 2.1.2 and 2.2.2. I think I may be running into a bug in Rails.

Best,

Marnen Laibow-Koser wrote:

Thanks for the suggestion. I tried the same test, and got interesting if disheartening results. When I had recipe[ingredient_lines] [ingredient][name] as the only form field, I got the same results as you. But the moment I added recipe[ingredient_lines][unit], [ingredient][name] stopped working. This was true both with Rails 2.1.2 and 2.2.2. I think I may be running into a bug in Rails.

Thanks for running that test.

Below is a patch that seems to fix the problem. I haven't yet run the rails test suite on it, nor added a test that would have broken the original.

Just run the patch command in actionpack-2.2.2/lib/action_controller

--- request.rb 2008-12-23 13:07:00.000000000 +1100 +++ request.rb.new 2008-12-23 14:37:30.000000000 +1100 @@ -811,9 +811,9 @@                 top[-1][key] = value               else                 top << {key => value}.with_indifferent_access - push top.last - value = top[key]               end + push top.last + value = top[key]             else               top << value             end

Mark Reginald James wrote:

Below is a patch that seems to fix the problem. I haven't yet run the rails test suite on it, nor added a test that would have broken the original.

I've confirmed that this patch fixes the problem without regression.

http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1622-incorrect-parsing-of-query-parameters-with-mixed-depth-nesting-inside-an-array

Mark Reginald James wrote: > Below is a patch that seems to fix the problem. I haven't > yet run the rails test suite on it, nor added a test that would > have broken the original.

I've confirmed that this patch fixes the problem without regression.

Hey, this is quite a Christmas present -- thanks very much! I was about to start poking around in the core to fix this, but you beat me to it. (The patch you posted here didn't actually work, but the one on the Lighthouse ticket did.) And it solves the problem beautifully.

#1622 Incorrect parsing of query parameters with mixed-depth nesting inside an array - Ruby on Rails - rails

I had already created a ticket for this, which Fred closed as a duplicate before I could do so. So we're cool. Thanks again.

Best,