Missing route parameter in nested resource - ruby-on-rails

Question

I am trying to include a resource into my routes file that shows the addresses of a customer via the url customers/1/addresses.
This is constructed with the following routes code:
resources :customers do
resources :addresses
end
However when I access the URL customers/1/addresses I'm thrown an exception
Couldn't find Customer with 'id'=
This error is caused by the following:
def set_customer
#customer = Customer.find(params[:id])
end
Now, this is because before the :show action is run on the customers controller it's calling the set_customer action.
How to only run the set_customer on the /customer/:customer_id: route?
And exclude set_customer on the /customer/:customer_id:/addresses/ route?
EDIT As Requested the Full Stack Trace
activerecord (4.2.1) lib/active_record/core.rb:155:in `find'
app/controllers/customers_controller.rb:67:in `set_customer'
activesupport (4.2.1) lib/active_support/callbacks.rb:432:in `block in make_lambda'
activesupport (4.2.1) lib/active_support/callbacks.rb:145:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:145:in `block in halting_and_conditional'
activesupport (4.2.1) lib/active_support/callbacks.rb:504:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:504:in `block in call'
activesupport (4.2.1) lib/active_support/callbacks.rb:504:in `each'
activesupport (4.2.1) lib/active_support/callbacks.rb:504:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:92:in `_run_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:776:in `_run_process_action_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.1) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.1) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.1) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (4.2.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.1) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.1) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.1) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.1) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.1) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.1) lib/action_controller/metal.rb:196:in `dispatch'
actionpack (4.2.1) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.1) lib/action_controller/metal.rb:237:in `block in action'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:74:in `call'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:74:in `dispatch'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:43:in `serve'
actionpack (4.2.1) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.1) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.1) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:819:in `call'
rack (1.6.4) lib/rack/etag.rb:24:in `call'
rack (1.6.4) lib/rack/conditionalget.rb:25:in `call'
rack (1.6.4) lib/rack/head.rb:13:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.4) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.4) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.1) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:649:in `call'
activerecord (4.2.1) lib/active_record/migration.rb:378:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.1) lib/active_support/callbacks.rb:88:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:88:in `_run_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:776:in `_run_call_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.1) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
web-console (2.1.3) lib/web_console/middleware.rb:37:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.1) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.1) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.1) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.1) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.1) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.1) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.4) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.4) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.1) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/static.rb:113:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
railties (4.2.1) lib/rails/engine.rb:518:in `call'
railties (4.2.1) lib/rails/application.rb:164:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
rack (1.6.4) lib/rack/handler/webrick.rb:88:in `service'
/Users/xavier/.rbenv/versions/2.2.0/lib/ruby/2.2.0/webrick/httpserver.rb:138:in `service'
/Users/xavier/.rbenv/versions/2.2.0/lib/ruby/2.2.0/webrick/httpserver.rb:94:in `run'
/Users/xavier/.rbenv/versions/2.2.0/lib/ruby/2.2.0/webrick/server.rb:294:in `block in start_thread'
EDIT customers_controller.rb
class CustomersController < ApplicationController
before_action :set_customer, only: [:show, :edit, :update, :destroy]
# GET /customers
# GET /customers.json
def index
#customers = Customer.all
end
# GET /customers/1
# GET /customers/1.json
def show
end
# GET /customers/new
def new
#customer = Customer.new
end
# GET /customers/1/edit
def edit
end
# POST /customers
# POST /customers.json
def create
#customer = Customer.new(customer_params)
respond_to do |format|
if #customer.save
format.html { redirect_to #customer, notice: 'Customer was successfully created.' }
format.json { render :show, status: :created, location: #customer }
else
format.html { render :new }
format.json { render json: #customer.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /customers/1
# PATCH/PUT /customers/1.json
def update
respond_to do |format|
if #customer.update(customer_params)
format.html { redirect_to #customer, notice: 'Customer was successfully updated.' }
format.json { render :show, status: :ok, location: #customer }
else
format.html { render :edit }
format.json { render json: #customer.errors, status: :unprocessable_entity }
end
end
end
# DELETE /customers/1
# DELETE /customers/1.json
def destroy
#customer.destroy
respond_to do |format|
format.html { redirect_to customers_url, notice: 'Customer was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_customer
#customer = Customer.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def customer_params
params.require(:customer).permit(:first_name, :middle_name, :last_name, :cyrillic_first_name, :cyrillic_middle_name, :cyrillic_last_name, :email_address, :hashed_password, allergen_ids: [])
end
end
Edit Addresses Controller
class AddressesController < ApplicationController
before_action :set_address, only: [:show, :edit, :update, :destroy]
# GET /addresses
# GET /addresses.json
def index
#addresses = Address.all
end
# GET /addresses/1
# GET /addresses/1.json
def show
end
# GET /addresses/new
def new
#address = Address.new
end
# GET /addresses/1/edit
def edit
end
# POST /addresses
# POST /addresses.json
def create
#address = Address.new(address_params)
respond_to do |format|
if #address.save
format.html { redirect_to #address, notice: 'Address was successfully created.' }
format.json { render :show, status: :created, location: #address }
else
format.html { render :new }
format.json { render json: #address.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /addresses/1
# PATCH/PUT /addresses/1.json
def update
respond_to do |format|
if #address.update(address_params)
format.html { redirect_to #address, notice: 'Address was successfully updated.' }
format.json { render :show, status: :ok, location: #address }
else
format.html { render :edit }
format.json { render json: #address.errors, status: :unprocessable_entity }
end
end
end
# DELETE /addresses/1
# DELETE /addresses/1.json
def destroy
#address.destroy
respond_to do |format|
format.html { redirect_to addresses_url, notice: 'Address was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_address
#address = Address.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def address_params
params[:address]
end
end

Answer 1

When you access a /customers/:id path, set_customer can do its job with params[:id], but at /customers/:customer_id/addresses, any :id is the Address ID. I'm not sure why set_customer is running at all given the code you've posted so far, but updating it to
Customer.find(params[:customer_id] || params[:id])
will let it work for both situations.

Answer 2

How to only run the set_customer on the /customer/:customer_id: route?
/customers/:customer_id: How's it possible? You are only gonna get customer_id if it is followed by addresses/:id like:
/customers/:customer_id/addresses/
/customers/:customer_id/addresses/new
/customers/:customer_id/addresses/:id/edit
And that actually corresponds the the show action in AddressesController.
And exclude set_customer on the /customer/:customer_id:/addresses/ route?
/customers/:customer_id/:addresses corresponds to index action in AddressesController, and there you can exclude set_customer for index action.