form_for with nested resources
Be sure to have both objects created in controller: @post
and @comment
for the post, eg:
@post = Post.find params[:post_id]
@comment = Comment.new(:post=>@post)
Then in view:
<%= form_for([@post, @comment]) do |f| %>
Be sure to explicitly define the array in the form_for, not just comma separated like you have above.
Travis R is correct. (I wish I could upvote ya.) I just got this working myself. With these routes:
resources :articles do
resources :comments
end
You get paths like:
/articles/42
/articles/42/comments/99
routed to controllers at
app/controllers/articles_controller.rb
app/controllers/comments_controller.rb
just as it says at http://guides.rubyonrails.org/routing.html#nested-resources, with no special namespaces.
But partials and forms become tricky. Note the square brackets:
<%= form_for [@article, @comment] do |f| %>
Most important, if you want a URI, you may need something like this:
article_comment_path(@article, @comment)
Alternatively:
[@article, @comment]
as described at http://edgeguides.rubyonrails.org/routing.html#creating-paths-and-urls-from-objects
For example, inside a collections partial with comment_item
supplied for iteration,
<%= link_to "delete", article_comment_path(@article, comment_item),
:method => :delete, :confirm => "Really?" %>
What jamuraa says may work in the context of Article, but it did not work for me in various other ways.
There is a lot of discussion related to nested resources, e.g. http://weblog.jamisbuck.org/2007/2/5/nesting-resources
Interestingly, I just learned that most people's unit-tests are not actually testing all paths. When people follow jamisbuck's suggestion, they end up with two ways to get at nested resources. Their unit-tests will generally get/post to the simplest:
# POST /comments
post :create, :comment => {:article_id=>42, ...}
In order to test the route that they may prefer, they need to do it this way:
# POST /articles/42/comments
post :create, :article_id => 42, :comment => {...}
I learned this because my unit-tests started failing when I switched from this:
resources :comments
resources :articles do
resources :comments
end
to this:
resources :comments, :only => [:destroy, :show, :edit, :update]
resources :articles do
resources :comments, :only => [:create, :index, :new]
end
I guess it's ok to have duplicate routes, and to miss a few unit-tests. (Why test? Because even if the user never sees the duplicates, your forms may refer to them, either implicitly or via named routes.) Still, to minimize needless duplication, I recommend this:
resources :comments
resources :articles do
resources :comments, :only => [:create, :index, :new]
end
Sorry for the long answer. Not many people are aware of the subtleties, I think.
You don't need to do special things in the form. You just build the comment correctly in the show action:
class ArticlesController < ActionController::Base
....
def show
@article = Article.find(params[:id])
@new_comment = @article.comments.build
end
....
end
and then make a form for it in the article view:
<% form_for @new_comment do |f| %>
<%= f.text_area :text %>
<%= f.submit "Post Comment" %>
<% end %>
by default, this comment will go to the create
action of CommentsController
, which you will then probably want to put redirect :back
into so you're routed back to the Article
page.