thenetimp
Reputation: 9820
Unable to understand ruby error
OK, so I am reading "Agile Web Development with Rails" and working on the depot application. For those who have the book it is Chapter 9.3 Iteration D3: Adding a button.
Prior to this section we created a session to hold our "shopping cart"
class ApplicationController < ActionController::Base
protect_from_forgery
private
def current_cart
Cart.find(session[:cart_id])
rescue ActiveRecord::RecordNotFound
cart = Cart.create
session[:cart_id] = cart.id
cart
end
end
Making it so any controller we create that extends ApplicationController has access to our cart.
In this section we edit the "create" function of the LineItemsController class which extends ApplicationControler.
The original create method looks like this
def create
@line_item = LineItem.new(params[:line_item])
respond_to do |format|
if @line_item.save
format.html { redirect_to @line_item, notice: 'Line item was successfully created.' }
format.json { render json: @line_item, status: :created, location: @line_item }
else
format.html { render action: "new" }
format.json { render json: @line_item.errors, status: :unprocessable_entity }
end
end
end
The book says to modify if like this.
def create
@cart = current_cart
product = Product.find(params[:product_id])
@line_item = @cart.line_items.build(product: product)
respond_to do |format|
if @line_item.save
format.html { redirect_to @line_item.cart, notice: 'Line item was successfully created.' }
format.json { render json: @line_item, status: :created, location: @line_item }
else
format.html { render action: "new" }
format.json { render json: @line_item.errors, status: :unprocessable_entity }
end
end
end
I've triple checked the code. I have duplicated it from the book. Not being a ruby expert I don't know what I am missing. The error it gives me is this.
ArgumentError in LineItemsController#create
wrong number of arguments (0 for 1)
Rails.root: /Users/jandrews/Projects/pragprog_ruby/depot
Application Trace | Framework Trace | Full Trace
activerecord (3.1.3) lib/active_record/relation.rb:318:in `destroy'
activerecord (3.1.3) lib/active_record/base.rb:442:in `destroy'
app/models/cart.rb:2:in `<class:Cart>'
app/models/cart.rb:1:in `<top (required)>'
activesupport (3.1.3) lib/active_support/dependencies.rb:456:in `load'
activesupport (3.1.3) lib/active_support/dependencies.rb:456:in `block in load_file'
activesupport (3.1.3) lib/active_support/dependencies.rb:640:in `new_constants_in'
activesupport (3.1.3) lib/active_support/dependencies.rb:455:in `load_file'
activesupport (3.1.3) lib/active_support/dependencies.rb:342:in `require_or_load'
activesupport (3.1.3) lib/active_support/dependencies.rb:489:in `load_missing_constant'
activesupport (3.1.3) lib/active_support/dependencies.rb:181:in `block in const_missing'
activesupport (3.1.3) lib/active_support/dependencies.rb:179:in `each'
activesupport (3.1.3) lib/active_support/dependencies.rb:179:in `const_missing'
activesupport (3.1.3) lib/active_support/dependencies.rb:501:in `load_missing_constant'
activesupport (3.1.3) lib/active_support/dependencies.rb:181:in `block in const_missing'
activesupport (3.1.3) lib/active_support/dependencies.rb:179:in `each'
activesupport (3.1.3) lib/active_support/dependencies.rb:179:in `const_missing'
app/controllers/application_controller.rb:7:in `current_cart'
app/controllers/line_items_controller.rb:43:in `create'
actionpack (3.1.3) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.1.3) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.1.3) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.1.3) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.1.3) lib/active_support/callbacks.rb:416:in `_run__1422100127945824718__process_action__3684163507935076470__callbacks'
activesupport (3.1.3) lib/active_support/callbacks.rb:386:in `_run_process_action_callbacks'
activesupport (3.1.3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.3) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.1.3) lib/action_controller/metal/rescue.rb:17:in `process_action'
actionpack (3.1.3) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.1.3) lib/active_support/notifications.rb:53:in `block in instrument'
activesupport (3.1.3) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.3) lib/active_support/notifications.rb:53:in `instrument'
actionpack (3.1.3) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.1.3) lib/action_controller/metal/params_wrapper.rb:201:in `process_action'
activerecord (3.1.3) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.1.3) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.1.3) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.1.3) lib/action_controller/metal.rb:193:in `dispatch'
actionpack (3.1.3) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.1.3) lib/action_controller/metal.rb:236:in `block in action'
actionpack (3.1.3) lib/action_dispatch/routing/route_set.rb:65:in `call'
actionpack (3.1.3) lib/action_dispatch/routing/route_set.rb:65:in `dispatch'
actionpack (3.1.3) lib/action_dispatch/routing/route_set.rb:29:in `call'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:152:in `block in call'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `block in recognize'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:75:in `optimized_each'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:95:in `recognize'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:141:in `call'
actionpack (3.1.3) lib/action_dispatch/routing/route_set.rb:532:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.3.6) lib/rack/etag.rb:23:in `call'
rack (1.3.6) lib/rack/conditionalget.rb:35:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/flash.rb:247:in `call'
rack (1.3.6) lib/rack/session/abstract/id.rb:195:in `context'
rack (1.3.6) lib/rack/session/abstract/id.rb:190:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/cookies.rb:331:in `call'
activerecord (3.1.3) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.1.3) lib/active_record/connection_adapters/abstract/connection_pool.rb:477:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (3.1.3) lib/active_support/callbacks.rb:392:in `_run_call_callbacks'
activesupport (3.1.3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.3) lib/action_dispatch/middleware/callbacks.rb:28:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/reloader.rb:68:in `call'
rack (1.3.6) lib/rack/sendfile.rb:101:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.1.3) lib/rails/rack/logger.rb:13:in `call'
rack (1.3.6) lib/rack/methodoverride.rb:24:in `call'
rack (1.3.6) lib/rack/runtime.rb:17:in `call'
activesupport (3.1.3) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.3.6) lib/rack/lock.rb:15:in `call'
actionpack (3.1.3) lib/action_dispatch/middleware/static.rb:53:in `call'
railties (3.1.3) lib/rails/engine.rb:456:in `call'
rack (1.3.6) lib/rack/content_length.rb:14:in `call'
rack (1.3.6) lib/rack/handler/webrick.rb:59:in `service'
/Users/jandrews/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/Users/jandrews/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/Users/jandrews/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
Request
Parameters:
{"authenticity_token"=>"tx+PRUMMQpyZ48Yw9ZLoWZ60HOo1992tpQXbKFkF4YM=",
"product_id"=>"5"}
Show session dump
Show env dump
Response
Headers:
None
The code that actually does the submit looks like this in the browser
<form action="/line_items?product_id=5" class="button_to" method="post">
<div>
<input type="submit" value="Add to Cart">
<input name="authenticity_token" type="hidden"
value="tx+PRUMMQpyZ48Yw9ZLoWZ60HOo1992tpQXbKFkF4YM=">
</div>
</form>
Sorry forgot to mention if I add the lines one by one from the original it fails on the line with. That's as far as I was able to debug since my knowledge of ruby is still limited atm.
@cart = current_cart
Cart model file.
class Cart < ActiveRecord::Base
has_many :line_items, dependent: destroy
end
Upvotes: 1
Views: 735
Answers (1)
keymone
Reputation: 8094
instead of
has_many :line_items, dependent: destroy
put
has_many :line_items, dependent: :destroy # the colon!!
Upvotes: 5
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