Ruby on rails 2 level model - ruby-on-rails

Question

I need some help creating a very simple forum in a existing model.
What I want in a Game page, have a mini forum, where is possible create some topics and some comments to this topics. In the beginning I'm only implement topics.
This is the error I have:
Mysql2::Error: Column 'user_id' cannot be null: INSERT INTO `topics` (`game_id`, `question`, `user_id`) VALUES (1, 'asd', NULL)
This is my main model:
game.rb
class Game < ActiveRecord::Base
attr_accessible :name
validates :user_id, presence: true
validates :name, presence: true, length: { maximum: 50 }
belongs_to :user
has_many :topics, dependent: :destroy
end
topic.rb
class Topic < ActiveRecord::Base
validates_presence_of :question
validates_presence_of :game_id
attr_accessible :question, :user_id
validates :question, length: {maximum: 50}, allow_blank: false
belongs_to :game
belongs_to :user
end
topic_controller.rb
def create
#game = Game.find(params[:game_id])
#topic = #game.topics.create(params[:topic])
#topic.user_id = current_user.id
respond_to do |format|
if #topic.save
format.html { redirect_to #game, notice: 'Topic was successfully created.' }
else
format.html { render action: "new" }
end
end
end
game/show.html.erb
<h2>Topics</h2>
<% #game.topics.each do |topic| %>
<p>
<b>Question:</b>
<%= topic.question %>
</p>
<% end %>
<h2>Add a topic:</h2>
<%= form_for([#game, #game.topics.build]) do |f| %>
<div class="field">
<%= f.label :question %><br />
<%= f.text_field :question %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
Thanks ;)

Answer 1

I believe the issue you're experiencing is the difference between create and new in Rails.
Using new merely initializes the model, allowing you to save/validate later; using create will perform all of those steps in one command, causing the database row to be created.
So when you attempt to perform
#game.topics.create(params[:topic])
Rails attempts to create a Topic using params[:topic] and setting the game_id to #game.id, after which it immediately attempts to validate this new Topic that it created and save it to the database.
Potential options that you can consider:
1) Use #game.topics.new(params[:topic])
2) merge {:user_id => current_user.id} in: #game.topics.create(params[:topic].merge({:user_id => current_user.id})
I'd personally suggest option 1 (i.e. using new instead), but I have seen option 2 used before.
EDIT: Another issue that it looks as though you might be experiencing: should current_user be #current_user in your code?
Side note:
generally, if create fails to create database row, it will still work (returning the initialized model instead), but in your case it looks like this won't happen due to database-level restrictions on user_id being NOT NULL, causing an uncaught error.

Answer 2

You may want to consider reading the Rails Guide on nested resources. I've been where you are now , take a look at this discusion.

Answer 3

I guess you're accessing the site without being logged in, so user_id will not be set. You should ensure that there is a logged in user for all actions that are modifying or creating a topic. A simple approach can be found in this Railscast.

Answer 4

I think current_user.id is not setting properly, Do inspect these issue are almost all the other issues, ruby debugger is the beset way
in your GEM file add
GEM file
gem 'debugger'
run bundle install
then in your controller
def create
#game = Game.find(params[:game_id])
#topic = #game.topics.create(params[:topic])
#topic.user_id = current_user.id
debugger
respond_to do |format|
if #topic.save
format.html { redirect_to #game, notice: 'Topic was successfully created.' }
else
format.html { render action: "new" }
end
end
end
and this will stop you in the the debugger line, then from the console you could see if the values are set or not. check this for more