I've gone through the full Shopping Cart tutorial on Chapter 7 several times, but still having big problems getting it to work.

There are many typos throughout the book, so I'm wondering if someone has found a typos in chapter 7 which could prevent the cart from loading.

My problem is:
The error occurred while evaluating nil.add_purchase
also reported on the error message is:
#{RAILS_ROOT}/app/controllers/buy_controller.rb:11:in `add'

Can anyone confirm that the tutorial actually works as is? or does anyone know if there is some typos in the book which culd cause this problem?

The fact that the tutorial has me editing 8 files before testing, doesn't help in debugging. I'll go through it from scratch a few more time and if still nothing, then the book hits the bin!

Perhaps I have just mistyped something!

Update number 1:

It appears that the code download from Wrox for Chapter 07 has many differences from the book I have.
Does nobody read these books before they get published?

Anyone want to by a nice Wrox Ruby on Rails book? sold as seen, I take no responsibility for the content within! (sorry, I'm going mad here)

Alright mate,

I know your post was some time ago and you've probably long since thrown your book in the bin, but are you still having problems?
I have managed to get everything up and running on my system and could give you a couple of pointers if you are still looking for help.

hi got this error
please help


NoMethodError in BuyController#add

undefined method `add_purchase' for #<Class:0x7fec3117d340>

RAILS_ROOT: /home/tulip/Desktop/Dhiru/rubydev/ch07/store
Application Trace | Framework Trace | Full Trace

vendor/rails/activerecord/lib/active_record/base.rb:1532:in `method_missing'
app/controllers/buy_controller.rb:10:in `add'

vendor/rails/activerecord/lib/active_record/base.rb:1532:in `method_missing'
vendor/rails/actionpack/lib/action_controller/base.rb:1158:in `send'
vendor/rails/actionpack/lib/action_controller/base.rb:1158:in `perform_action_without_filters'
vendor/rails/actionpack/lib/action_controller/filters.rb:697:in `call_filters'
vendor/rails/actionpack/lib/action_controller/filters.rb:689:in `perform_action_without_benchmark'
vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/1.8/benchmark.rb:293:in `measure'
vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
vendor/rails/actionpack/lib/action_controller/rescue.rb:199:in `perform_action_without_caching'
vendor/rails/actionpack/lib/action_controller/caching.rb:678:in `perform_action'
vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:33:in `cache'
vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache'
vendor/rails/actionpack/lib/action_controller/caching.rb:677:in `perform_action'
vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send'
vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters'
vendor/rails/actionpack/lib/action_controller/filters.rb:685:in `process_without_session_management_support'
vendor/rails/actionpack/lib/action_controller/session_management.rb:123:in `process'
vendor/rails/actionpack/lib/action_controller/base.rb:388:in `process'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:171:in `handle_request'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:115:in `dispatch'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:126:in `dispatch_cgi'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:9:in `dispatch'
vendor/rails/railties/lib/webrick_server.rb:112:in `handle_dispatch'
vendor/rails/railties/lib/webrick_server.rb:78:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
/usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:95:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `each'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:23:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:82:in `start'
vendor/rails/railties/lib/webrick_server.rb:62:in `dispatch'
vendor/rails/railties/lib/commands/servers/webrick.rb:66
/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `require'
vendor/rails/activesupport/lib/active_support/dependencies.rb:496:in `require'
vendor/rails/activesupport/lib/active_support/dependencies.rb:342:in `new_constants_in'
vendor/rails/activesupport/lib/active_support/dependencies.rb:496:in `require'
vendor/rails/railties/lib/commands/server.rb:39
script/server:3:in `require'
script/server:3

vendor/rails/activerecord/lib/active_record/base.rb:1532:in `method_missing'
app/controllers/buy_controller.rb:10:in `add'
vendor/rails/actionpack/lib/action_controller/base.rb:1158:in `send'
vendor/rails/actionpack/lib/action_controller/base.rb:1158:in `perform_action_without_filters'
vendor/rails/actionpack/lib/action_controller/filters.rb:697:in `call_filters'
vendor/rails/actionpack/lib/action_controller/filters.rb:689:in `perform_action_without_benchmark'
vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/1.8/benchmark.rb:293:in `measure'
vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
vendor/rails/actionpack/lib/action_controller/rescue.rb:199:in `perform_action_without_caching'
vendor/rails/actionpack/lib/action_controller/caching.rb:678:in `perform_action'
vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:33:in `cache'
vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache'
vendor/rails/actionpack/lib/action_controller/caching.rb:677:in `perform_action'
vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send'
vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters'
vendor/rails/actionpack/lib/action_controller/filters.rb:685:in `process_without_session_management_support'
vendor/rails/actionpack/lib/action_controller/session_management.rb:123:in `process'
vendor/rails/actionpack/lib/action_controller/base.rb:388:in `process'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:171:in `handle_request'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:115:in `dispatch'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:126:in `dispatch_cgi'
vendor/rails/actionpack/lib/action_controller/dispatcher.rb:9:in `dispatch'
vendor/rails/railties/lib/webrick_server.rb:112:in `handle_dispatch'
vendor/rails/railties/lib/webrick_server.rb:78:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
/usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:95:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `each'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:23:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:82:in `start'
vendor/rails/railties/lib/webrick_server.rb:62:in `dispatch'
vendor/rails/railties/lib/commands/servers/webrick.rb:66
/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:27:in `require'
vendor/rails/activesupport/lib/active_support/dependencies.rb:496:in `require'
vendor/rails/activesupport/lib/active_support/dependencies.rb:342:in `new_constants_in'
vendor/rails/activesupport/lib/active_support/dependencies.rb:496:in `require'
vendor/rails/railties/lib/commands/server.rb:39
script/server:3:in `require'
script/server:3

Request

Parameters:

{"id"=>"1"}

Show session dump
{:csrf_id=>"26fe6c38b2792a7436b18f04139baa03", :shopping_cart=>Purchase(id: integer, item_id: integer, quantity: integer, price: decimal), "flash"=>{}}
Response

Headers:

{"cookie"=>[],
"Cache-Control"=>"no-cache"}