ruby on rails - unknown action in controller - routes.rb issue? weird results by changing from singular to plural? -

i'm getting strange reaction 'destroy' method. error when trying destroy project:

unknown action action '5' not found projectscontroller 

i figured out when when change routes.rb file resources :projects (plural) resources :project (singular), destroy action works should (and returns index) show method works update , new methods throw undefined methodprojects_path'` errors. why happening??

class projectscontroller < applicationcontroller      def index     @projects = project.sorted     end      def show     @project = project.find(params[:id])     end      def new      @project = project.new     @project_count = project.count + 1     end    def create     # instantiate new object using form parameters     @project = project.new(project_params)     # save object     if @project.save       # if save succeeds, redirect index action       flash[:notice] = "project created successfully."       redirect_to(:action => 'index')     else       # if save fails, redisplay form user can fix problems       @project_count = project.count + 1       render('new')     end   end   def edit     @project = project.find(params[:id])     @project_count = project.count   end    def update     @project = project.find(params[:id])     if @project.update_attributes(project_params)       flash[:notice] = "project updated successfully."       redirect_to(:action => 'show', :id => @project.id)     else       @project_count = project.count       render('edit')     end   end   def delete     @project = project.find(params[:id])   end    def destroy     project = project.find(params[:id])     project.destroy     flash[:notice] = "project '#{project.name}' destroyed successfully."     redirect_to(:action => 'index')   end  private      def project_params         params.require(:project).permit(:name, :financing, :visible, :position)     end end 

routes.rb file:

 rails.application.routes.draw        root :to => 'projects#index'       resources :projects        match ':controller(/:action(/:id))', :via => [:get, :post]       # priority based upon order of creation: first created -> highest priority.       # see how routes lay out "rake routes".        # can have root of site routed "root"       # root 'welcome#index'        # example of regular route:       #   'products/:id' => 'catalog#view'        # example of named route can invoked purchase_url(id: product.id)       #   'products/:id/purchase' => 'catalog#purchase', as: :purchase        # exampl  e resource route (maps http verbs controller actions automatically):   #   resources :products    # example resource route options:   #   resources :products   #     member   #       'short'   #       post 'toggle'   #     end   #   #     collection   #       'sold'   #     end   #   end    # example resource route sub-resources:   #   resources :products   #     resources :comments, :sales   #     resource :seller   #   end    # example resource route more complex sub-resources:   #   resources :products   #     resources :comments   #     resources :sales   #       'recent', on: :collection   #     end   #   end    # example resource route concerns:   #   concern :toggleable   #     post 'toggle'   #   end   #   resources :posts, concerns: :toggleable   #   resources :photos, concerns: :toggleable    # example resource route within namespace:   #   namespace :admin   #     # directs /admin/products/* admin::productscontroller   #     # (app/controllers/admin/products_controller.rb)   #     resources :products   #   end end 

delete.html.erb page:

<% @page_title = "delete project" %>  <%= link_to("<< list", {:action => 'index'}, :class => 'back-link') %>  <div class="project destroy">   <h2>delete projects</h2>    <%= form_for(:project, :url => {:action => 'destroy', :id => @project.id}) |f| %>      <p>are sure want permanently delete project?</p>      <p class="reference-name"><%= @project.name %></p>      <div class="form-buttons">       <%= submit_tag("delete project") %>     </div>    <% end %> </div> 

[update] interesting update. messed around destroy , changed controller to:

 def delete     @project = project.find(params[:id])     @project.destroy    end    def destroy     project = project.find(params[:id])     project.destroy     flash[:notice] = "project '#{project.name}' destroyed successfully."     redirect_to(:action => 'index')   end 

i did see if issue destroy method. destroy project, , still returns delete page causes same error, destroy it.

though doing couple of unconventional stuff having delete.html.erb (objects deleted show view page), i'm going address direct question.

you said:

"when change routes.rb file resources :projects (plural) resources :project (singular), destroy action works should (and returns index) show method works update , new methods throw undefined method projects_path'` errors. why happening??"

you have understand every time change routes, have modify helper paths in views.

example: when had resources :projects, helper methods (run rake db:migrate)

projects_path            /projects(.:format)          projects#index                      post    /projects(.:format)          projects#create new_project_path         /projects/new(.:format)      projects#new edit_project_path        /projects/:id/edit(.:format) projects#edit project_path             /projects/:id(.:format)      projects#show                      patch   /projects/:id(.:format)      projects#update                      put     /projects/:id(.:format)      projects#update                      delete  /projects/:id(.:format)      projects#destroy 

so @ point, projects_path working because can see above, projects_path there.

when changed routes resources :project(singular), helper paths change well. run rake db:migrate see them:

project_index_path       /project(.:format)  project#index                      post    /project(.:format)  project#create                          /project/new(.:format)  project#new                          /project/:id/edit(.:format)     project#edit                          /project/:id(.:format)  project#show                      patch   /project/:id(.:format)  project#update                      put     /project/:id(.:format)  project#update                      delete  /project/:id(.:format)  project#destroy 

as can see helper path maps project#index project_index_path.

so i'm guessing in edit.html.erb (or somewhere else) have old code: projects_path , getting undefined method projects_path because helper no longer exist. correct helper method in case, project_index_path.