Agile Web Development with Rails, Edition 5
10.2 Iteration E2: Handling Errors
9.4 Playtime
10.1 Iteration E1: Creating a Smarter Cart
Change the cart to track the quantity of each product.
Add a quantity column to the line_item table in the database.
rails generate migration add_quantity_to_line_items quantity:integer
invoke active_record
create db/migrate/20170326074128_add_quantity_to_line_items.rb
Modify the migration to add a default value for the new column
edit db/migrate/20170326074128_add_quantity_to_line_items.rb
class AddQuantityToLineItems < ActiveRecord::Migration[5.0]
def change
add_column :line_items, :quantity, :integer, default: 1
end
end
Apply the migration
rails db:migrate
mv 20170326074128_add_quantity_to_line_items.rb 20170326000004_add_quantity_to_line_items.rb
== 20170326000004 AddQuantityToLineItems: migrating ===========================
-- add_column(:line_items, :quantity, :integer, {:default=>1})
-> 0.0023s
== 20170326000004 AddQuantityToLineItems: migrated (0.0023s) ==================
Create a method to add a product to the cart by either incrementing the quantity of an existing line item, or creating a new line item.
edit app/models/cart.rb
def add_product(product)
current_item = line_items.find_by(product_id: product.id)
if current_item
current_item.quantity += 1
else
current_item = line_items.build(product_id: product.id)
end
current_item
end
Replace the call to LineItem.new with a call to the new method.
edit app/controllers/line_items_controller.rb
def create
product = Product.find(params[:product_id])
@line_item = @cart.add_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 :show,
status: :created, location: @line_item }
else
format.html { render :new }
format.json { render json: @line_item.errors,
status: :unprocessable_entity }
end
end
end
Update the view to show both columns.
edit app/views/carts/show.html.erb
<p id="notice"><%= notice %></p>
<h2>Your Pragmatic Cart</h2>
<ul>
<% @cart.line_items.each do |item| %>
<li><%= item.quantity %> × <%= item.product.title %></li>
<% end %>
</ul>
Look at the cart, and see that's not exactly what we intended
get /carts/1
Your Pragmatic Cart
- 1 × Seven Mobile Apps in Seven Weeks
- 1 × Seven Mobile Apps in Seven Weeks
Generate a migration to combine/separate items in carts.
rails generate migration combine_items_in_cart
invoke active_record
create db/migrate/20170326074130_combine_items_in_cart.rb
Fill in the self.up method
edit db/migrate/20170326074130_combine_items_in_cart.rb
def up
# replace multiple items for a single product in a cart with a
# single item
Cart.all.each do |cart|
# count the number of each product in the cart
sums = cart.line_items.group(:product_id).sum(:quantity)
sums.each do |product_id, quantity|
if quantity > 1
# remove individual items
cart.line_items.where(product_id: product_id).delete_all
# replace with a single item
item = cart.line_items.build(product_id: product_id)
item.quantity = quantity
item.save!
end
end
end
end
Combine entries
rails db:migrate
mv 20170326074130_combine_items_in_cart.rb 20170326000005_combine_items_in_cart.rb
== 20170326000005 CombineItemsInCart: migrating ===============================
== 20170326000005 CombineItemsInCart: migrated (0.0324s) ======================
Verify that the entries have been combined.
get /carts/1
Your Pragmatic Cart
- 2 × Seven Mobile Apps in Seven Weeks
Fill in the self.down method
edit db/migrate/20170326000005_combine_items_in_cart.rb
def down
# split items with quantity>1 into multiple items
LineItem.where("quantity>1").each do |line_item|
# add individual items
line_item.quantity.times do
LineItem.create(
cart_id: line_item.cart_id,
product_id: line_item.product_id,
quantity: 1
)
end
# remove original item
line_item.destroy
end
end
Separate out individual items.
rails db:rollback
== 20170326000005 CombineItemsInCart: reverting ===============================
== 20170326000005 CombineItemsInCart: reverted (0.0294s) ======================
rails db:migrate:status
database: /home/rubys/git/awdwr/edition4/work-50/depot/db/development.sqlite3
Status Migration ID Migration Name
--------------------------------------------------
up 20170326000001 Create products
up 20170326000002 Create carts
up 20170326000003 Create line items
up 20170326000004 Add quantity to line items
down 20170326000005 Combine items in cart
mv db/migrate/20170326000005_combine_items_in_cart.rb db/migrate/20170326000005_combine_items_in_cart.bak
Every item should (once again) only have a quantity of one.
get /carts/1
Your Pragmatic Cart
- 1 × Seven Mobile Apps in Seven Weeks
- 1 × Seven Mobile Apps in Seven Weeks
Recombine the item data.
mv db/migrate/20170326000005_combine_items_in_cart.bak db/migrate/20170326000005_combine_items_in_cart.rb
rails db:migrate
== 20170326000005 CombineItemsInCart: migrating ===============================
== 20170326000005 CombineItemsInCart: migrated (0.0325s) ======================
Add a few products to the order.
post /line_items?product_id=2
You are being
redirected.
get http://localhost:3000/carts/1
Line item was successfully created.
Your Pragmatic Cart
- 2 × Seven Mobile Apps in Seven Weeks
- 1 × Rails, Angular, Postgres, and Bootstrap
post /line_items?product_id=3
You are being
redirected.
get http://localhost:3000/carts/1
Line item was successfully created.
Your Pragmatic Cart
- 3 × Seven Mobile Apps in Seven Weeks
- 1 × Rails, Angular, Postgres, and Bootstrap
fix the test case
edit test/controllers/line_items_controller_test.rb
test "should create line_item" do
assert_difference('LineItem.count') do
post line_items_url, params: { product_id: products(:ruby).id }
end
follow_redirect!
assert_select 'h2', 'Your Pragmatic Cart'
assert_select 'li', "1 \u00D7 Programming Ruby 1.9"
end
rerun tests
rails test
Run options: --seed 17597
# Running:
............................
Finished in 0.651124s, 43.0026 runs/s, 89.0768 assertions/s.
28 runs, 58 assertions, 0 failures, 0 errors, 0 skips
Try something malicious.
get /carts/wibble
HTTP Response Code: 404
ActiveRecord::RecordNotFound
in CartsController#show
Couldn't find Cart with 'id'=wibble
Extracted source (around line #173):
171
172
173
174
175
176
|
record = statement.execute([id], self, connection).first
unless record
raise RecordNotFound.new("Couldn't find #{name} with '#{primary_key}'=#{id}",
name, primary_key, id)
end
record
|
Extracted source (around line #67):
65
66
67
68
69
70
|
# Use callbacks to share common setup or constraints between actions.
def set_cart
@cart = Cart.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
|
Extracted source (around line #382):
380
381
382
383
384
385
|
case filter
when Symbol
lambda { |target, _, &blk| target.send filter, &blk }
when String
l = eval "lambda { |value| #{filter} }"
lambda { |target, value| target.instance_exec(value, &l) }
|
Extracted source (around line #150):
148
149
150
151
152
153
|
if !halted && user_conditions.all? { |c| c.call(target, value) }
result_lambda = -> { user_callback.call target, value }
env.halted = halted_lambda.call(target, result_lambda)
if env.halted
target.send :halted_callback_hook, filter
|
Extracted source (around line #12):
10
11
12
13
14
15
|
included do
define_callbacks :process_action,
terminator: ->(controller, result_lambda) { result_lambda.call if result_lambda.is_a?(Proc); controller.performed? },
skip_after_callbacks_if_terminated: true
end
|
Extracted source (around line #151):
149
150
151
152
153
154
|
if !halted && user_conditions.all? { |c| c.call(target, value) }
result_lambda = -> { user_callback.call target, value }
env.halted = halted_lambda.call(target, result_lambda)
if env.halted
target.send :halted_callback_hook, filter
end
|
Extracted source (around line #454):
452
453
454
455
456
457
|
def call(arg)
@before.each { |b| b.call(arg) }
value = @call.call(arg)
@after.each { |a| a.call(arg) }
value
|
Extracted source (around line #454):
452
453
454
455
456
457
|
def call(arg)
@before.each { |b| b.call(arg) }
value = @call.call(arg)
@after.each { |a| a.call(arg) }
value
|
Extracted source (around line #454):
452
453
454
455
456
457
|
def call(arg)
@before.each { |b| b.call(arg) }
value = @call.call(arg)
@after.each { |a| a.call(arg) }
value
|
Extracted source (around line #101):
99
100
101
102
103
104
|
runner = callbacks.compile
e = Filters::Environment.new(self, false, nil, block)
runner.call(e).value
end
end
|
Extracted source (around line #750):
748
749
750
751
752
753
|
module_eval <<-RUBY, __FILE__, __LINE__ + 1
def _run_#{name}_callbacks(&block)
__run_callbacks__(_#{name}_callbacks, &block)
end
RUBY
end
|
Extracted source (around line #90):
88
89
90
91
92
93
|
# end
def run_callbacks(kind, &block)
send "_run_#{kind}_callbacks", &block
end
private
|
Extracted source (around line #19):
17
18
19
20
21
22
|
# process_action callbacks around the normal behavior.
def process_action(*args)
run_callbacks(:process_action) do
super
end
end
|
Extracted source (around line #20):
18
19
20
21
22
23
|
private
def process_action(*args)
super
rescue Exception => exception
request.env['action_dispatch.show_detailed_exceptions'] ||= show_detailed_exceptions?
rescue_with_handler(exception) || raise
|
Extracted source (around line #32):
30
31
32
33
34
35
|
ActiveSupport::Notifications.instrument("process_action.action_controller", raw_payload) do |payload|
begin
result = super
payload[:status] = response.status
result
ensure
|
Extracted source (around line #164):
162
163
164
165
166
167
|
def instrument(name, payload = {})
if notifier.listening?(name)
instrumenter.instrument(name, payload) { yield payload if block_given? }
else
yield payload if block_given?
end
|
Extracted source (around line #21):
19
20
21
22
23
24
|
listeners_state = start name, payload
begin
yield payload
rescue Exception => e
payload[:exception] = [e.class.name, e.message]
payload[:exception_object] = e
|
Extracted source (around line #164):
162
163
164
165
166
167
|
def instrument(name, payload = {})
if notifier.listening?(name)
instrumenter.instrument(name, payload) { yield payload if block_given? }
else
yield payload if block_given?
end
|
Extracted source (around line #30):
28
29
30
31
32
33
|
ActiveSupport::Notifications.instrument("start_processing.action_controller", raw_payload.dup)
ActiveSupport::Notifications.instrument("process_action.action_controller", raw_payload) do |payload|
begin
result = super
payload[:status] = response.status
|
Extracted source (around line #248):
246
247
248
249
250
251
|
request.filtered_parameters.merge! wrapped_filtered_hash
end
super
end
private
|
Extracted source (around line #18):
16
17
18
19
20
21
|
# and it won't be cleaned up by the method below.
ActiveRecord::LogSubscriber.reset_runtime
super
end
def cleanup_view_runtime
|
Extracted source (around line #126):
124
125
126
127
128
129
|
@_response_body = nil
process_action(action_name, *args)
end
# Delegates to the class' ::controller_path
|
Extracted source (around line #30):
28
29
30
31
32
33
|
def process(*) #:nodoc:
old_config, I18n.config = I18n.config, I18nProxy.new(I18n.config, lookup_context)
super
ensure
I18n.config = old_config
end
|
Extracted source (around line #190):
188
189
190
191
192
193
|
set_request!(request)
set_response!(response)
process(name)
request.commit_flash
to_a
end
|
Extracted source (around line #262):
260
261
262
263
264
265
|
middleware_stack.build(name) { |env| new.dispatch(name, req, res) }.call req.env
else
new.dispatch(name, req, res)
end
end
end
|
Extracted source (around line #50):
48
49
50
51
52
53
|
def dispatch(controller, action, req, res)
controller.dispatch(action, req, res)
end
end
|
Extracted source (around line #32):
30
31
32
33
34
35
|
controller = controller req
res = controller.make_response! req
dispatch(controller, params[:action], req, res)
rescue ActionController::RoutingError
if @raise_on_name_error
raise
|
Extracted source (around line #39):
37
38
39
40
41
42
|
req.path_parameters = set_params.merge parameters
status, headers, body = route.app.serve(req)
if 'pass' == headers['X-Cascade']
req.script_name = script_name
|
Extracted source (around line #26):
24
25
26
27
28
29
|
def serve(req)
find_routes(req).each do |match, parameters, route|
set_params = req.path_parameters
path_info = req.path_info
script_name = req.script_name
|
Extracted source (around line #26):
24
25
26
27
28
29
|
def serve(req)
find_routes(req).each do |match, parameters, route|
set_params = req.path_parameters
path_info = req.path_info
script_name = req.script_name
|
Extracted source (around line #725):
723
724
725
726
727
728
|
req = make_request(env)
req.path_info = Journey::Router::Utils.normalize_path(req.path_info)
@router.serve(req)
end
def recognize_path(path, environment = {})
|
Extracted source (around line #25):
23
24
25
26
27
28
|
def call(env)
status, headers, body = @app.call(env)
if etag_status?(status) && etag_body?(body) && !skip_caching?(headers)
original_body = body
|
Extracted source (around line #25):
23
24
25
26
27
28
|
case env[REQUEST_METHOD]
when "GET", "HEAD"
status, headers, body = @app.call(env)
headers = Utils::HeaderHash.new(headers)
if status == 200 && fresh?(env, headers)
status = 304
|
Extracted source (around line #12):
10
11
12
13
14
15
|
def call(env)
status, headers, body = @app.call(env)
if env[REQUEST_METHOD] == HEAD
[
|
Extracted source (around line #222):
220
221
222
223
224
225
|
req = make_request env
prepare_session(req)
status, headers, body = app.call(req.env)
res = Rack::Response::Raw.new status, headers
commit_session(req, res)
[status, headers, body]
|
Extracted source (around line #216):
214
215
216
217
218
219
|
def call(env)
context(env)
end
def context(env, app=@app)
|
Extracted source (around line #613):
611
612
613
614
615
616
|
request = ActionDispatch::Request.new env
status, headers, body = @app.call(env)
if request.have_cookie_jar?
cookie_jar = request.cookie_jar
|
Extracted source (around line #553):
551
552
553
554
555
556
|
end
end
@app.call(env)
end
private
|
Extracted source (around line #38):
36
37
38
39
40
41
|
result = run_callbacks :call do
begin
@app.call(env)
rescue => error
end
end
|
Extracted source (around line #97):
95
96
97
98
99
100
|
def __run_callbacks__(callbacks, &block)
if callbacks.empty?
yield if block_given?
else
runner = callbacks.compile
e = Filters::Environment.new(self, false, nil, block)
|
Extracted source (around line #750):
748
749
750
751
752
753
|
module_eval <<-RUBY, __FILE__, __LINE__ + 1
def _run_#{name}_callbacks(&block)
__run_callbacks__(_#{name}_callbacks, &block)
end
RUBY
end
|
Extracted source (around line #90):
88
89
90
91
92
93
|
# end
def run_callbacks(kind, &block)
send "_run_#{kind}_callbacks", &block
end
private
|
Extracted source (around line #36):
34
35
36
37
38
39
|
def call(env)
error = nil
result = run_callbacks :call do
begin
@app.call(env)
rescue => error
|
Extracted source (around line #12):
10
11
12
13
14
15
|
state = @executor.run!
begin
response = @app.call(env)
returned = response << ::Rack::BodyProxy.new(response.pop) { state.complete! }
ensure
state.complete! unless returned
|
Extracted source (around line #79):
77
78
79
80
81
82
|
req = ActionDispatch::Request.new env
req.remote_ip = GetIp.new(req, check_ip, proxies)
@app.call(req.env)
end
# The GetIp class exists as a way to defer processing of the request data
|
Extracted source (around line #49):
47
48
49
50
51
52
|
def call(env)
request = ActionDispatch::Request.new env
_, headers, body = response = @app.call(env)
if headers['X-Cascade'] == 'pass'
body.close if body.respond_to?(:close)
|
Extracted source (around line #135):
133
134
135
136
137
138
|
def call_app(env)
@app.call(env)
rescue => e
throw :app_exception, e
end
|
Extracted source (around line #28):
26
27
28
29
30
31
|
end
status, headers, body = call_app(env)
if session = Session.from(Thread.current) and acceptable_content_type?(headers)
response = Response.new(body, status, headers)
|
Extracted source (around line #18):
16
17
18
19
20
21
|
def call(env)
app_exception = catch :app_exception do
request = create_regular_or_whiny_request(env)
return call_app(env) unless request.from_whitelisted_ip?
|
Extracted source (around line #18):
16
17
18
19
20
21
|
def call(env)
app_exception = catch :app_exception do
request = create_regular_or_whiny_request(env)
return call_app(env) unless request.from_whitelisted_ip?
|
Extracted source (around line #31):
29
30
31
32
33
34
|
def call(env)
request = ActionDispatch::Request.new env
@app.call(env)
rescue Exception => exception
if request.show_exceptions?
render_exception(request, exception)
|
Extracted source (around line #36):
34
35
36
37
38
39
|
instrumenter.start 'request.action_dispatch', request: request
logger.info { started_request_message(request) }
resp = @app.call(env)
resp[2] = ::Rack::BodyProxy.new(resp[2]) { finish(request) }
resp
rescue Exception
|
Extracted source (around line #24):
22
23
24
25
26
27
|
if logger.respond_to?(:tagged)
logger.tagged(compute_tags(request)) { call_app(request, env) }
else
call_app(request, env)
end
|
Extracted source (around line #69):
67
68
69
70
71
72
|
def tagged(*tags)
formatter.tagged(*tags) { yield self }
end
def flush
|
Extracted source (around line #26):
24
25
26
27
28
29
|
def tagged(*tags)
new_tags = push_tags(*tags)
yield self
ensure
pop_tags(new_tags.size)
end
|
Extracted source (around line #69):
67
68
69
70
71
72
|
def tagged(*tags)
formatter.tagged(*tags) { yield self }
end
def flush
|
Extracted source (around line #24):
22
23
24
25
26
27
|
if logger.respond_to?(:tagged)
logger.tagged(compute_tags(request)) { call_app(request, env) }
else
call_app(request, env)
end
|
Extracted source (around line #13):
11
12
13
14
15
16
|
::Rails.logger.silence { @app.call(env) }
else
@app.call(env)
end
end
end
|
Extracted source (around line #24):
22
23
24
25
26
27
|
req = ActionDispatch::Request.new env
req.request_id = make_request_id(req.x_request_id)
@app.call(env).tap { |_status, headers, _body| headers[X_REQUEST_ID] = req.request_id }
end
private
|
Extracted source (around line #22):
20
21
22
23
24
25
|
end
@app.call(env)
end
def method_override(env)
|
Extracted source (around line #22):
20
21
22
23
24
25
|
def call(env)
start_time = Utils.clock_time
status, headers, body = @app.call(env)
request_time = Utils.clock_time - start_time
unless headers.has_key?(@header_name)
|
Extracted source (around line #28):
26
27
28
29
30
31
|
def call(env)
LocalCacheRegistry.set_cache_for(local_cache_key, LocalStore.new)
response = @app.call(env)
response[2] = ::Rack::BodyProxy.new(response[2]) do
LocalCacheRegistry.set_cache_for(local_cache_key, nil)
end
|
Extracted source (around line #12):
10
11
12
13
14
15
|
state = @executor.run!
begin
response = @app.call(env)
returned = response << ::Rack::BodyProxy.new(response.pop) { state.complete! }
ensure
state.complete! unless returned
|
Extracted source (around line #136):
134
135
136
137
138
139
|
end
@app.call(req.env)
end
end
end
|
Extracted source (around line #111):
109
110
111
112
113
114
|
def call(env)
status, headers, body = @app.call(env)
if body.respond_to?(:to_path)
case type = variation(env)
when 'X-Accel-Redirect'
|
Extracted source (around line #522):
520
521
522
523
524
525
|
def call(env)
req = build_request env
app.call req.env
end
# Defines additional Rack env configuration that is added on each call.
|
Extracted source (around line #224):
222
223
224
225
226
227
|
def call(env)
env[Const::PUMA_CONFIG] = @config
@app.call(env)
end
end
|
Extracted source (around line #600):
598
599
600
601
602
603
|
begin
begin
status, headers, res_body = @app.call(env)
return :async if req.hijacked
|
Extracted source (around line #435):
433
434
435
436
437
438
|
while true
case handle_request(client, buffer)
when false
return
when :async
|
Extracted source (around line #299):
297
298
299
300
301
302
|
else
if process_now
process_client client, buffer
else
client.set_timeout @first_data_timeout
@reactor.add client
|
Extracted source (around line #120):
118
119
120
121
122
123
|
begin
block.call(work, *extra)
rescue Exception => e
STDERR.puts "Error reached top of thread-pool: #{e.message} (#{e.class})"
end
|
Rails.root: /home/rubys/git/awdwr/edition4/work-50/depot
Request
Parameters:
{"id"=>"wibble"}
_csrf_token: "Q/X85JrPvNKl6aqoot314skc6SuVo8/p8EfEjG+CYi0="
cart_id: 1
session_id: "f54bf3a2d403d5854dde02385fbfa940"
GATEWAY_INTERFACE: "CGI/1.2"
HTTP_ACCEPT: "text/html"
HTTP_ACCEPT_ENCODING: "gzip;q=1.0,deflate;q=0.6,identity;q=0.3"
HTTP_VERSION: "HTTP/1.1"
ORIGINAL_SCRIPT_NAME: ""
REMOTE_ADDR: "127.0.0.1"
SERVER_NAME: "localhost"
SERVER_PROTOCOL: "HTTP/1.1"
Response
Headers:
None
10.2 Iteration E2: Handling Errors
9.4 Playtime
