ruby on rails has_many relation form validation of children - ruby-on-rails

Question

I followed the tutorial to create the blog application. So I have posts and comments. The validation for fields in the posts form works perfect. The validation in the comments section of a post works as well, but I cant get the errors to be printed.
The comment model:
class Comment
belongs_to :post
validates :commenter, :presence => true
end
The comment controller:
def create
#post = Post.find(params[:post_id])
#comment = #post.comments.build(params[:comment])
if #comment.save
redirect_to post_path(#post)
else
render :template => 'posts/show'
end
end
def destroy
#post = Post.find(params[:post_id])
#comment = #post.comments.find(params[:id])
#comment.destroy
render :template => 'posts/show'
end
The post controller:
def index
#posts = Post.all
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => #posts }
end
end
def show
#post = Post.find(params[:id])
#comment = #post.comments.build #added
##comment = #Comment.new #added
respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => #post }
end
end
def new
#post = Post.new
respond_to do |format|
format.html # new.html.erb
format.xml { render :xml => #post }
end
end
def edit
#post = Post.find(params[:id])
end
def create
#post = Post.new(params[:post])
respond_to do |format|
if #post.save
format.html { redirect_to(#post, :notice => 'Post was successfully created.') }
format.xml { render :xml => #post, :status => :created, :location => #post }
else
format.html { render :action => "new" }
format.xml { render :xml => #post.errors, :status => :unprocessable_entity }
end
end
end
def update
#post = Post.find(params[:id])
respond_to do |format|
if #post.update_attributes(params[:post])
format.html { redirect_to(#post, :notice => 'Post was successfully updated.') }
format.xml { head :ok }
else
format.html { render :action => "edit" }
format.xml { render :xml => #post.errors, :status => :unprocessable_entity }
end
end
end
def destroy
#post = Post.find(params[:id])
#post.destroy
respond_to do |format|
format.html { redirect_to(posts_url) }
format.xml { head :ok }
end
end
And I use in the form:
<%= form_for([#post, #post.comments.build]) do |f| %>
How would I get the .errors for the comments? If I try I always get: undefined method `errors' or nil object.
Please help, I am completely new to rails.
Thanks!
Picki

Answer 1

The problem is, that you're building the comment new every time you're loading the form. Like this, the comment with the validation errors never makes it into your form.
Create the comment instead in your controller, something like this — details depending on your application:
# posts controller
def show
#post = Post.find(params[:id])
#comment = Comment.new
end
# comments controller
def create
#post = Post.find(params[:post_id])
#comment = #post.comments.build(params[:comment])
if #comment.save
redirect_to #post
else
render :new
end
end
And change your form:
<%= form_for([#post, #comment]) do |f| %>