rails - undefined method all for forum:Module

Question

i am trying to implement a forum page using the tutorial in this page!. Here Forum is a model. This is the controller code:

class ForumsController < ApplicationController
  before_filter :admin_required, :except => [:index, :show]

  def index
    @forums = Forum.all
  end

  def show
    @forum = Forum.find(params[:id])
  end

  def new
    @forum = Forum.new
  end

  def create
    @forum = Forum.new(params[:forum])
    if @forum.save
      redirect_to @forum, :notice => "Successfully created forum."
    else
      render :action => 'new'
    end
  end

  def edit
    @forum = Forum.find(params[:id])
  end

  def update
    @forum = Forum.find(params[:id])
    if @forum.update_attributes(params[:forum])
      redirect_to @forum, :notice  => "Successfully updated forum."
    else
      render :action => 'edit'
    end
  end

  def destroy
    @forum = Forum.find(params[:id])
    @forum.destroy
    redirect_to forums_url, :notice => "Successfully destroyed forum."
  end
end

the error is :

undefined method `all' for Forum:Module

Here is the forum model ( models/forum.rb):

class Forum < ActiveRecord::Base
  attr_accessible :name, :description
  has_many :topics, :dependent => :destroy

  #method to find the most recent forum topics
  def most_recent_post  
  topic = Topic.first(:order => 'last_post_at DESC', :conditions => ['forum_id = ?', self.id])  
  return topic  
end  
end

How can i rectify this error? I am new to ROR and unable to find a proper solution for this error.

Answer 1

The error above is saying there is no method defined for the Module Forum. However, the definition of Forum clearly shows that's a class, not a module.

The only explanation is that you have another definition of Forum somewhere in your application, where you define it as a Module, that is loaded before the model and it conflicts with your application.

Be very careful you didn't call your application Forum, otherwise the main application namespace will conflict with your model (there is a high chance that's the problem). In this case, you either rename your application or (easier) the model. In fact, the application namespace is defined as module.

Search the source code of your application for a Forum module definition and remove it. It may also be in a gem (very unlikely, but not impossible) so make sure you know the source code of the dependencies your are using.

Answer 2

This could be something to do with your routes.

Try in config/routes.rb

root :to => 'forums#index'

instead of

map.root :controller => 'forums'

It's a rails 2/3 thing and I think this tutorial is written in 2.

If you are trying to learn Rails, I recommend Michael Hartl's Rails Tutorial.