Question

So I have a self-joining model defined. Basically a post on a forum, and a parent_post that it belongs to.

class Post < ActiveRecord::Base
  has_many :replies, :class_name => "Post"
  belongs_to :thread, :class_name => "Post", :foreign_key => "parent_post_id"
end

Which seems fundamentally sound. I created a new RESTful route for the reply action, and an action and view.

Routes:

  resources :forums do
    resources :posts do
      member do
        get 'reply'
      end
    end
  end

The view layer and the control action seems to be where I’m getting hosed up.

def reply
  @forum = Forum.find(params[:forum_id])
  @post = @forum.posts.build
  @post.thread = @forum.posts.find(params[:id])
  @post.title = "RE: #{@post.thread.title}"
end

def create
  @forum = Forum.find(params[:forum_id])
  @post = @forum.posts.build(params[:post])
  @post.user = current_user
  if @post.save
    redirect_to forum_post_path(@forum, @post), notice: 'Post was successfully created.'
  else
    render action: "new"
  end
end

And in the view layer I was just trying to use the same scaffold generated form partial I’m using for the standard new and edit actions.

#reply.html.erb
<%= render :partial => 'form' %>

#_form.html.erb
<%= form_for [@forum,@post], :html => { :class => 'form-horizontal' } do |f| %>
  <fieldset>
    <legend><h1>New Thread</h1></legend>

    <div class="control-group">
      <%= f.label :title, :class => 'control-label' %>
      <div class="controls">
        <%= f.text_field :title, :class => 'text_field span9' %>
      </div>
    </div>
        <div class="control-group">
      <%= f.label :body, :class => 'control-label' %>
      <div class="controls">
        <%= f.text_area :body, :class => 'text_area span9' %>
      </div>
    </div>
    <div class="form-actions">
      <%= f.submit 'Submit', :class => 'btn btn-primary' %>
      <%= link_to 'Cancel', forum_posts_path(@forum), :class => 'btn' %>
    </div>
  </fieldset>
<% end %>

However, the parent_post_id is getting lost when I’m creating the post and it’s getting set to nil. Do I need to create another action? Is there some other way to set the thread? Some third thing?

Answer 1

This will work:

Reply action:

@forum = Forum.find(params[:forum_id])
@post = @forum.posts.build
@post.thread = @forum.posts.find(params[:id])
@post.title = "RE: #{@post.thread.title}"

Then add this to your view

<%= f.hidden_field :parent_post_id, @post.thread.id %>

BTW I question whether you need a custom reply method as opposed to using built-in RESTful methods but this should fix your problem and that wasn’t really your question.