Using link_to for creating a link to a view from a different controller

Question

I'm new to Rails and am working towards creating a hyper link in 'views/admins/show.html.erb' that loads 'views/residents/new.html.erb'. In the name of clarity 'views/admins/show.html.erb' and 'views/residents/new.html.erb' are from separate controllers. I am stumped on finding solutions to my routing failures, and am generating the following message:

NameError in Admins#show

Showing /Users/beracus/rails_projects/whizcharts/app/views/admins/show.html.erb where line #11 raised:

undefined local variable or method `residents_new' for

<#:0x000001019a2228> Extracted source (around line #11):

11: <%= link_to 'create a new resident', residents_new %>

I would like to figure out how to successfully create a hyper-link in Rails that enables me to link to other views/partials whether or not they are from the same controller. Also I would like to better understand what my error message means to help prevent this in the future. Any guidance to documentation is appreciated, as well as pointing out any design rules I may be violating. I've searched for and found similar challenges posed to others, but due to my inexperience, I've not yet been able to cater those solutions to my needs.

I have tried the following.

Here's my code:

    # config/routes.rb
     Sample::Application.routes.draw do
      resources :admins do
        resources :residents
      end
      resources :sessions, only: [:new, :create, :destroy]

      root to: 'static_pages#home'

      match '/signup',    to: 'admins#new'
      match '/signin',    to: 'sessions#new'
      match '/signout',   to: 'sessions#destroy', via: :delete

      match '/help',      to: 'static_pages#help'
      match '/about',     to: 'static_pages#about'
      match '/contact',   to: 'static_pages#contact'
          .
          .
          .
      match ':controller(/:action(/:id))(.:format)'
    end


    # controllers/admins_controller.rb

    class AdminsController < ApplicationController
    before_filter :signed_in_admin, only: [:index, :edit, :update]
    before_filter :correct_admin,   only: [:edit, :update]
    before_filter :super_admin, only: :destroy

    def index
        @admins = Admin.paginate(page: params[:page]) 
    end

    def show
        @admin = Admin.find(params[:id])
    end

    def new
        @admin = Admin.new
    end

    def create
        @admin = Admin.new(params[:admin])
        if @admin.save
            sign_in @admin
            flash[:success] = "Welcome to Whizcharts!"
            redirect_to @admin
        else
            render 'new'
        end
    end

    def edit
        @admin = Admin.find(params[:id])
    end

    def update
        @admin = Admin.find(params[:id])
        if @admin.update_attributes(params[:admin])
            flash[:success] = "Profile updated"
            sign_in @admin
            redirect_to @admin
        else
            render 'edit'
        end
    end

    def destroy
        Admin.find(params[:id]).destroy
        flash[:success] = "User deleted."
        redirect_to admins_path
    end

    private

        def signed_in_admin
            unless signed_in?
            store_location
            redirect_to signin_path, notice: "Please sign in."
        end

        def correct_admin
            @admin = Admin.find(params[:id])
            redirect_to(root_path) unless current_admin?(@admin)
        end

        def super_admin
            redirect_to(root_path) unless current_admin.super?
        end
    end
end


# controllers/residents_controller.rb

class ResidentsController < ApplicationController
  def index
    @residents = Resident.paginate(page: params[:page])
  end

  def show
    @resident = Resident.find(params[:id])
  end

  def new
    @resident = Resident.new
  end

  def create
    @resident = Resident.new(params[:resident])
  end

  def edit
    @resident = Resident.find(params[:id])
  end

  def update
    @resdient = Resident.find(params[:id])
    if @resident.update_attributes(params{:resident})
        flash[:success] = "Resident's profile updated"
        sign_in @resident
        redirect_to @resident
    else
      render 'edit'
    end
  end

  def destroy
    Resident.find(params[:id]).destroy
    flash[:success] = "Resident deleted"
    redirect_to residents_path
  end

  def _form
    @residents = Resident.paginate(page: params[:page])
  end
end


# views/admins/show.html.erb

<% provide(:title, @admin.fname + " " + @admin.lname) %>
<div class="row">
    <aside class="span4">
        <section>
            <h1>
                <%= gravatar_for @admin %>
                <%= @admin.fname + " " + @admin.lname %> 
            </h1>
        </section>
        <section class="resident">
            <%= link_to 'create a new resident', residents_new %>
        </section>
    </aside>
</div>

# views/residents/new.html.erb
<% provide(:title, @admin.fname + " " + @admin.lname) %>
<div class="row">
    <aside class="span4">
        <section>
            <h1>
                <%= gravatar_for @admin %>
                <%= @admin.fname + " " + @admin.lname %> 
            </h1>
        </section>
        <section class="resident">
            <%= link_to 'create a new resident', residents_new %>
        </section>
    </aside>
</div>

# views/residents/form.html.erb 

<%= form_for(@resident) do |f| %>
    <% if @resident.error.any? %>
        <div id="error_explanation">
            <h2>
                <%= pluralize(@resident.errors.count, "error") %>
                prohibited this resident from being saved:
            </h2>
            <ul>
                <% @resident.errors.full_messages.each do |msg| %>
                <li><%= msg %></li>
                <% end %>
            </ul>
        </div>
    <% end %>

    <div class="field">
        <%= f.label :fname %><br />
        <%= f.text_field :fname %>
    </div>
    <div class="field">
        <%= f.label :lname %><br />
        <%= f.text_field :lname %>
    </div>
    <div class="field">
        <%= f.label :dob %><br />
        <%= f.text_field :dob %>
    </div>
    <div class="field">
        <%= f.radio_button :gender, 'Male' %>
        <%= f.label "gender", "Male" %>
        <br />
        <%= f.radio_button :gender, 'Female' %>
        <%= f.label "gender", "Female" %>
        <br />
        <%= f.radio_button :gender, 'Other' %>
        <%= f.label "gender", "Other" %>
        <br />
    </div>
    <div class="field">
        <%= f.label :soc %><br />
        <%= f.text_field :soc %><br />
    </div>
    <div class="field">
        <%= f.label :address %><br />
        <%= f.text_field :address %>
    </div>
    <div class="field">
        <%= f.label :city %><br />
        <%= f.text_field :city %>
    </div>
    <div class="field">
        <%= f.label :state %><br />
        <%= f.text_field :state %>
    </div>
    <div class="field">
        <%= f.label :zip %><br />
        <%= f.text_field :zip %>
    </div>
    <div class="field">
        <%= f.label :phone %><br />
        <%= f.text_field :phone %>
    </div>
    <div class="field">
        <%= f.label :doc_fname %><br />
        <%= f.text_field :doc_fname %>
    </div>
    <div class="field">
        <%= f.label :doc_lname %><br />
        <%= f.text_field :doc_lname %>
    </div>
    <div class="field">
        <%= f.label :doc_phone1 %><br />
        <%= f.text_field :doc_phone1 %>
    </div>
    <div class="field">
        <%= f.label :doc_phone2 %><br />
        <%= f.text_field :doc_phone2 %>
    </div>
    <div class="field">
        <%= f.label :doc_fax %><br />
        <%= f.text_field :doc_fax %>
    </div>
    <div class="field">
        <%= f.label :doc_email %><br />
        <%= f.text_field :doc_email %>
    </div>
    <div class="field">
        <%= f.label :guard_fname %><br />
        <%= f.text_field :guard_fname %>
    </div>
    <div class="field">
        <%= f.label :guard_lname %><br />
        <%= f.text_field :guard_lname %>
    </div>
    <div class="field">
        <%= f.label :guard_address %><br />
        <%= f.text_field :guard_address %>
    </div>
    <div class="field">
        <%= f.label :guard_city %><br />
        <%= f.text_field :guard_city %>
    </div>
    <div class="field">
        <%= f.label :guard_state %><br />
        <%= f.text_field :guard_state %>
    </div>
    <div class="field">
        <%= f.label :guard_zip %><br />
        <%= f.text_field :guard_zip %><br />
    </div>
    <div class="field">
        <%= f.label :guard_phone1 %><br />
        <%= f.text_field :guard_phone1 %>
    </div>
    <div class="field">
        <%= f.label :guard_phone2 %><br />
        <%= f.text_field :guard_phone2 %>
    </div>
    <div class="field">
        <%= f.label :guard_email %><br />
        <%= f.text_field :guard_email %>
    </div>
    <div class="actions">
        <%= f.submit %>
    </div>
    <% end %>


# rake routes 

Mac-Pro:whizcharts beracus$ rake routes
    admin_residents GET    /admins/:admin_id/residents(.:format)          residents#index
                    POST   /admins/:admin_id/residents(.:format)          residents#create
 new_admin_resident GET    /admins/:admin_id/residents/new(.:format)      residents#new
edit_admin_resident GET    /admins/:admin_id/residents/:id/edit(.:format) residents#edit
     admin_resident GET    /admins/:admin_id/residents/:id(.:format)      residents#show
                    PUT    /admins/:admin_id/residents/:id(.:format)      residents#update
                    DELETE /admins/:admin_id/residents/:id(.:format)      residents#destroy
             admins GET    /admins(.:format)                              admins#index
                    POST   /admins(.:format)                              admins#create
          new_admin GET    /admins/new(.:format)                          admins#new
         edit_admin GET    /admins/:id/edit(.:format)                     admins#edit
              admin GET    /admins/:id(.:format)                          admins#show
                    PUT    /admins/:id(.:format)                          admins#update
                    DELETE /admins/:id(.:format)                          admins#destroy
           sessions POST   /sessions(.:format)                            sessions#create
        new_session GET    /sessions/new(.:format)                        sessions#new
            session DELETE /sessions/:id(.:format)                        sessions#destroy
               root        /                                              static_pages#home
             signup        /signup(.:format)                              admins#new
             signin        /signin(.:format)                              sessions#new
            signout DELETE /signout(.:format)                             sessions#destroy
               help        /help(.:format)                                static_pages#help
              about        /about(.:format)                               static_pages#about
            contact        /contact(.:format)                             static_pages#contact
                           /admin(.:format)                               admins#index
               show        /show(.:format)                                admins#show
                new        /new(.:format)                                 admins#new
             create        /create(.:format)                              admins#create
               edit        /edit(.:format)                                admins#edit
             update        /update(.:format)                              admins#update
            destroy        /destroy(.:format)                             admins#destroy
          residents        /residents(.:format)                           residents#path
               form        /form(.:format)                                residents#form
                           /create(.:format)                              residents#create
                           /destroy(.:format)                             residents#destroy
                           /edit(.:format)                                residents#edit
              index        /index(.:format)                               residents#index
                           /new(.:format)                                 residents#new
                           /show(.:format)                                residents#show
                           /update(.:format)                              residents#update
                           /:controller(/:action(/:id))(.:format)         :controller#:action

Your routes file is quite messy too. You're redefining the same routes several times ... — Anthony Alberto, Sep 10 '12 at 21:02

Nick Kugaevsky · Accepted Answer · 2012-09-10T21:25:28.867

0

Is it really necessary to use all these match for admins and residents in config/routes.rb?

You've already created resourceful routes with

resources :admins do 
  resources :residents
end

Anyway new_admin_resident_path helper should solve your problem for nested resource. Or new_resident_path helper for unnested.

<%= link_to 'Create a new resident', new_admin_resident_path %>

edited Sep 10 '12 at 21:25

answered Sep 10 '12 at 20:54

Nick Kugaevsky

2,935
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Thank you both for helping me rid the redundancies in my routes file. There was no reason to have that duplication. I looked up the documentation on resources making helpers available to the controller (section 2.3) [link]http://guides.rubyonrails.org/routing.html and added the new_admin_resident_path. I recieve a routing error saying no route matches for the action 'new' controller 'residents'. I tried unnesting my resources but received the same error msg. What steps am I overlooking? – sirramongabriel Sep 11 '12 at 15:52
Correction: When un-nesting my resources and providing <%= link_to 'Create a new resident', new_resident_path %>. I revieve an argument error saying 'Range unspecified. Specify the :in, :within, :maximum, :minimum, or :is option.' – sirramongabriel Sep 11 '12 at 16:10
Ok I figured it out. I had a trail of typos from my model but what you instructed me on Nick was the solution to my problem. Thank you. – sirramongabriel Sep 11 '12 at 21:07

Using link_to for creating a link to a view from a different controller

<#:0x000001019a2228> Extracted source (around line #11):

1 Answers1