Question

I’ve searched my problem high and low on here and haven’t quite found the right answer. I think it might be a simple routes issue. On my app, a user can create a project and follow “plants” through their project before ever having to officially sign up. The routes for updating and editing the project itself work fine. The error I get “couldn’t find Project without an ID” only occurs after I try accessing the CREATE action in my “Prelationships” controller to build a relationship between the “Project” and the “Plants.” My code is below:

My routes.rb

resources :sessions,       :only => [:new, :create, :destroy]
resources :microposts,     :only => [:create, :destroy]
resources :relationships,  :only => [:create, :destroy]  
resources :prelationships, :only => [:create]
resources :plants   
resources :projects do        
  member do
   get :pfollowing, :pfollowers  
  end
end       

My “Prelationships” controller

class PrelationshipsController < ApplicationController

  def create   
    @project = Project.find(params[:project_id])                                   
    @plant = Plant.find(params[:prelationship][:pfollowed_id])
    @project.pfollow!(@plant)
    respond_to do |format|
      format.html { redirect_to @project }
      format.js { redirect_to @project }
    end
  end
end

My “Prelationships” model

class Prelationship < ActiveRecord::Base                          
attr_accessible :pfollowed_id

belongs_to :pfollower, :class_name => "Project"
belongs_to :pfollowed, :class_name => "Plant"

validates :pfollower_id, :presence => true
validates :pfollowed_id, :presence => true
end                

My “Projects” model

class Project < ActiveRecord::Base                    
attr_accessible :title, :address, :latitude, :longitude, :state      

belongs_to :user        
has_many :prelationships, :foreign_key => "pfollower_id",
                        :dependent => :destroy   
has_many :pfollowing, :through => :prelationships, :source => :pfollowed          

  def pfollowing?(pfollowed)
    prelationships.find_by_pfollowed_id(pfollowed)  
  end  

  def pfollow!(pfollowed)
    prelationships.create!(:pfollowed_id => pfollowed.id)
  end
end    

My “Plants” model

class Plant < ActiveRecord::Base      

has_many :prelationships, :foreign_key => "pfollowed_id",
                        :class_name => "Prelationship"
has_many :pfollowers, :through => :reverse_prelationships, 
                    :source => :pfollower   
end

My partial for building the relationship on the @project ‘show’ page

<%= form_for @project.prelationships.build(:pfollowed_id =>
                                 @project_id) do |f| %>
<%= collection_select(:prelationship, :pfollower_id, Plant.all, :id, :name, options =   
{:prompt => "Select your plants"}, :class => "listselect") %>
<div class="actions">
<%= f.submit "Pfollow" %>
 </div>
<% end %>

The error message is “Could not find Project without an ID” once I hit submit on the partial.

app/controllers/prelationships_controller.rb:4:in `create'

and the Parameters:

{"utf8"=>"✓",
"authenticity_token"=>"NKqa1f0M2yPLQDHbRLnxl3SiwBeTus/1q1hpZjD7hgY=",
"prelationship"=>{"pfollower_id"=>"5"},"commit"=>"Pfollow"}  

If this is a routes issue, I can’t seem to find the right language to fix it. I’ve built a User model with the ability to follow other users and did not have these problems, which leads me to believe I might have to create a session for my project?

Help this newbie, please!

Answer 1

The simple way:

<%= form_for @project.prelationships.build(:pfollowed_id =>
                             @project_id) do |f| %>
    <%= collection_select(:prelationship, :pfollower_id, Plant.all, :id, :name, options =   
    {:prompt => "Select your plants"}, :class => "listselect") %>
    <%= hidden_field_tag :project_id, @project.id %>
    <div class="actions">
        <%= f.submit "Pfollow" %>
    </div>
<% end %>

And the right way would be creating a nested route on projects, but you can do this refactoring as an exercise for later.