I have a two-part question about form_for and nested resources. Let's say I'm writing a blog engine and I want to relate a comment to an article. I've defined a nested resource as follows:
map.resources :articles do |articles|
articles.resources :comments
end
The comment form is in the show.html.erb view for articles, underneath the article itself, for instance like this:
<%= render :partial => "articles/article" %>
<% form_for([ :article, @comment]) do |f| %>
<%= f.text_area :text %>
<%= submit_tag "Submit" %>
<% end %>
This gives an error, "Called id for nil, which would mistakenly etc." I've also tried
<% form_for @article, @comment do |f| %>
Which renders correctly but relates f.text_area to the article's 'text' field instead of the comment's, and presents the html for the article.text attribute in that text area. So I seem to have this wrong as well. What I want is a form whose 'submit' will call the create action on CommentsController, with an article_id in the params, for instance a post request to /articles/1/comments.
The second part to my question is, what's the best way to create the comment instance to begin with? I'm creating a @comment in the show action of the ArticlesController, so a comment object will be in scope for the form_for helper. Then in the create action of the CommentsController, I create new @comment using the params passed in from the form_for.
Thanks!
This question is related to
ruby-on-rails
form-for
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.
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.
Source: Stackoverflow.com