Question

I’m using a custom action to get the id of a project into the session, so that only relevant info for that project is shown in other areas. I’ve made a custom action in the projects controller, and am having trouble getting a link to work in the view to call that action. I just get an error saying “Couldn’t find project without ID”. I’m new to rails – I know it’s probably an easy question, but help would be much appreciated, thanks!

View Code:

<%= link_to 'Select Project', :action => :select_project %>

Controller Code:

def select_project
  @project = Project.find(params[:id])
  session[:project_id] = @project.id
end

Routes:

resources :projects do
  collection do
    get :select_project
  end
end

Alternative routes code:

resources :projects do
  put 'select_project', on: :member
end

Answer 1

This is untested but I believe it is what you are looking for:

Routes:

resources :projects do
  member do
    post :set_current
  end
end

this should create the following:

• Endpoint: /projects/:id/set_current POST
• Helper: set_current_project_path

Controller

def set_current
  project = Project.find(params[:id])
  session[:project_id] = project.id
  redirect_to projects_path, :notice => "Current project set to #{project.name}"
end

Views

# index / erb tags excluded for simplicity 
@projects.each do |project|
  link_to 'Select Project', set_current_project_path(project), :method => :post
end

# show
<%= link_to 'Select Project', set_current_project_path(@project), :method => :post %>

See:

• http://guides.rubyonrails.org/routing.html#adding-more-restful-actions
• http://guides.rubyonrails.org/routing.html#crud-verbs-and-actions

Note also the use of ‘post’ instead of ‘get’, since we are changing the state of an object (session)
it is preferred to use a post not a get, otherwise users might pull up an old get request in the address bar
of their browser and set their session to a project unknowingly.

like varatis said – use rake routes or CONTROLLER=projects rake routes to help with determining what your route/path helpers look like and what http verbs they are expecting

---

And is there a reason why it’s project not @project in the controller

The @project creates an instance variable; in a rails controller instance variables are made available to the views. This set_current action will never render a view, so no reason to make an instance variable out of it.

---

How come you have to set it to member and not collection in the routes

any action where you want to reference params[:id] should be a member route, an alternative would be to leave it as a collection route and pass params[:project_id] and pass that in all of your link_to calls, but in this case member makes more sense.

I believe resources :projects is a short cut for this break down

member do
  get :show
  get :edit
  put :update      
  delete :destroy
end
collection do
  get :index
  get :new
  post :create
end

hopefully that clarifies your questions some?