Question

I have an app that allows users to add courses to their profile. This is done through my ‘lineups’ model. To give you an idea of my database and schema:

#relationships
Class User
  has_many :lineups
end 

Class Course
  has_many :lineups
end

Class Lineup
  belongs_to :user
  belongs_to :course
end 

#some schema
create_table "lineups", :force => true do |t|
    t.integer  "course_id"
    t.integer  "user_id"
end

Now, I have a page were courses are listed with an ‘add course’ button. When clicked, a form submits to my ‘Lineup’ controller to the ‘create’ action. This process works great, however, my code that checks to see if a user has already added a course fails. The course will be added again. Here is my controller code:

class LineupsController < ApplicationController
    def create 
        course_id = params[:course_id]
        user_id = current_user.id
        course_object = Course.find(course_id) 

            #THIS BLOCK DOES NOT WORK
        for lineup in current_user.lineups do
            if lineup.course.id == course_id
                return redirect_to course_query_url, :alert => "You have already added this course: #{course_object.cl} #{course_object.cn}" 
            end
        end
            #THE BLOCK ^^^ DOES NOT WORK

        new_lineup = Lineup.new( course_id: course_id, user_id: user_id)

        respond_to do |format|
            if new_lineup.save 
                format.html { redirect_to course_query_url, :notice => "Course added: #{course_object.cl} #{course_object.cn}" }
            else
                format.html { redirect_to course_query_url, :alert => "There was an error in adding the course: #{course_object.cl} #{course_object.cn}" }
            end
        end
    end

end

I know that this line works, b/c I have it working in a view:

for lineup in current_user.lineups do

And I know that when the above line is iterated, the ‘lineup’ instance is created and the relationships work find (ie ‘lineup.course.id’) b/c it is also used in a view. Here is the code from the view in which this loop works:

      <% if current_user.lineups %>
        <% for lineup in current_user.lineups do %>
          <li><%= link_to "#{lineup.course.id} #{lineup.course.cn}", index_path %></li>
        <% end %>
      <% end %>

I am really at my wits end here and cannot figure out why this conditional is not working. Any and all input would be appreciated.

Answer 1

Your are comparing number (course.id) and string (params[:id]) in this line

if lineup.course.id == course_id

This does not work in Ruby 🙂

Try to change to

if lineup.course.id.to_s == course_id

or

if lineup.course.id == course_id.to_i