Agile Web Development with Rails, Edition 5
6.1 Iteration A1: Creating the Products Maintenance Application
Table of Contents
2 Instant Gratification
We start with a simple "hello world!" demo application and in the process verify that everything is installed correctly.
Create the application
bundle exec /home/rubys/git/rails/railties/exe/rails new demo1 --skip-bundle --skip-listen
create
create README.md
create Rakefile
create .ruby-version
create config.ru
create .gitignore
create Gemfile
run git init from "."
Initialized empty Git repository in /home/rubys/git/awdwr/edition4/work/demo1/.git/
create package.json
create app
create app/assets/config/manifest.js
create app/assets/javascripts/application.js
create app/assets/javascripts/cable.js
create app/assets/stylesheets/application.css
create app/channels/application_cable/channel.rb
create app/channels/application_cable/connection.rb
create app/controllers/application_controller.rb
create app/helpers/application_helper.rb
create app/jobs/application_job.rb
create app/mailers/application_mailer.rb
create app/models/application_record.rb
create app/views/layouts/application.html.erb
create app/views/layouts/mailer.html.erb
create app/views/layouts/mailer.text.erb
create app/assets/images/.keep
create app/assets/javascripts/channels
create app/assets/javascripts/channels/.keep
create app/controllers/concerns/.keep
create app/models/concerns/.keep
create bin
create bin/bundle
create bin/rails
create bin/rake
create bin/setup
create bin/update
create bin/yarn
create config
create config/routes.rb
create config/application.rb
create config/environment.rb
create config/cable.yml
create config/puma.rb
create config/spring.rb
create config/storage.yml
create config/environments
create config/environments/development.rb
create config/environments/production.rb
create config/environments/test.rb
create config/initializers
create config/initializers/application_controller_renderer.rb
create config/initializers/assets.rb
create config/initializers/backtrace_silencers.rb
create config/initializers/cookies_serializer.rb
create config/initializers/cors.rb
create config/initializers/filter_parameter_logging.rb
create config/initializers/inflections.rb
create config/initializers/mime_types.rb
create config/initializers/new_framework_defaults_5_2.rb
create config/initializers/wrap_parameters.rb
create config/locales
create config/locales/en.yml
create config/master.key
create config/boot.rb
create config/database.yml
create db
create db/seeds.rb
create lib
create lib/tasks
create lib/tasks/.keep
create lib/assets
create lib/assets/.keep
create log
create log/.keep
create public
create public/404.html
create public/422.html
create public/500.html
create public/apple-touch-icon-precomposed.png
create public/apple-touch-icon.png
create public/favicon.ico
create public/robots.txt
create test/fixtures
create test/fixtures/.keep
create test/fixtures/files
create test/fixtures/files/.keep
create test/controllers
create test/controllers/.keep
create test/mailers
create test/mailers/.keep
create test/models
create test/models/.keep
create test/helpers
create test/helpers/.keep
create test/integration
create test/integration/.keep
create test/test_helper.rb
create test/system
create test/system/.keep
create test/application_system_test_case.rb
create storage
create storage/.keep
create tmp/storage
create tmp/storage/.keep
exist tmp
create tmp/.keep
create tmp/cache
create tmp/cache/assets
create vendor
create vendor/.keep
remove config/initializers/cors.rb
remove config/initializers/new_framework_defaults_5_2.rb
Active Storage installation was skipped. Please run `bin/rails active_storage:install` to install Active Storage files.
bundle install --local
Resolving dependencies...
Using rake 12.2.1
Using concurrent-ruby 1.0.5
Using i18n 0.9.1
Using minitest 5.10.3
Using thread_safe 0.3.6
Using tzinfo 1.2.4
Using activesupport 5.2.0.alpha from source at `/home/rubys/git/rails`
Using builder 3.2.3
Using erubi 1.7.0
Using mini_portile2 2.3.0
Using nokogiri 1.8.1
Using rails-dom-testing 2.0.3
Using crass 1.0.2
Using loofah 2.1.1
Using rails-html-sanitizer 1.0.3
Using actionview 5.2.0.alpha from source at `/home/rubys/git/rails`
Using rack 2.0.3
Using rack-test 0.7.0
Using actionpack 5.2.0.alpha from source at `/home/rubys/git/rails`
Using nio4r 2.1.0
Using websocket-extensions 0.1.3
Using websocket-driver 0.6.5
Using actioncable 5.2.0.alpha from source at `/home/rubys/git/rails`
Using globalid 0.4.1
Using activejob 5.2.0.alpha from source at `/home/rubys/git/rails`
Using mini_mime 1.0.0
Using mail 2.7.0
Using actionmailer 5.2.0.alpha from source at `/home/rubys/git/rails`
Using activemodel 5.2.0.alpha from source at `/home/rubys/git/rails`
Using arel 9.0.0.alpha from source at `/home/rubys/git/arel`
Using activerecord 5.2.0.alpha from source at `/home/rubys/git/rails`
Using activestorage 5.2.0.alpha from source at `/home/rubys/git/rails`
Using public_suffix 3.0.1
Using addressable 2.5.2
Using io-like 0.3.0
Using archive-zip 0.7.0
Using bindex 0.5.0
Using msgpack 1.1.0
Using bootsnap 1.1.5
Using bundler 1.16.0
Using byebug 9.1.0
Using xpath 2.1.0
Using capybara 2.15.4
Using ffi 1.9.18
Using childprocess 0.8.0
Using chromedriver-helper 1.1.0
Using coffee-script-source 1.12.2
Using execjs 2.7.0
Using coffee-script 2.4.1
Using method_source 0.9.0
Using thor 0.19.4
Using railties 5.2.0.alpha from source at `/home/rubys/git/rails`
Using coffee-rails 4.2.2
Using et-orbi 1.0.8
Using multi_json 1.12.2
Using jbuilder 2.7.0
Using mono_logger 1.1.0
Using mustermann 1.0.1
Using pg 0.19.0
Using puma 3.10.0
Using queue_classic 3.2.0.RC1 from source at `/home/rubys/git/queue_classic`
Using rack-protection 2.0.0
Using sprockets 3.7.1
Using sprockets-rails 3.2.1
Using rails 5.2.0.alpha from source at `/home/rubys/git/rails`
Using rb-fsevent 0.10.2
Using rb-inotify 0.9.9 from source at `/home/rubys/git/rb-inotify`
Using redis 4.0.1
Using redis-namespace 1.6.0
Using tilt 2.0.8
Using sinatra 2.0.0
Using vegas 0.1.11
Using resque 1.27.4
Using rufus-scheduler 3.4.2
Using resque-scheduler 4.3.0 from source at `/home/rubys/git/resque-scheduler`
Using rubyzip 1.2.1
Using sass-listen 4.0.0
Using sass 3.5.3
Using sass-rails 5.0.6 from source at `/home/rubys/git/sass-rails`
Using selenium-webdriver 3.7.0
Using spring 2.0.2
Using sqlite3 1.3.13
Using turbolinks-source 5.0.3
Using turbolinks 5.0.1
Using uglifier 3.2.0
Using web-console 3.5.1 from source at `/home/rubys/git/web-console`
Bundle complete! 20 Gemfile dependencies, 86 gems now installed.
Use `bundle info [gemname]` to see where a bundled gem is installed.
Start the server.
get /
Yay! You’re on Rails!
Rails version: 5.2.0.alpha
Ruby version: 2.4.1 (x86_64-linux)
See what files were created
ls -p
app/ config.ru Gemfile.lock package.json README.md tmp/
bin/ db/ lib/ public/ storage/ vendor/
config/ Gemfile log/ Rakefile test/
Create a simple controller
rails generate controller Say hello goodbye
create app/controllers/say_controller.rb
route get 'say/hello'
get 'say/goodbye'
invoke erb
create app/views/say
create app/views/say/hello.html.erb
create app/views/say/goodbye.html.erb
invoke test_unit
create test/controllers/say_controller_test.rb
invoke helper
create app/helpers/say_helper.rb
invoke test_unit
invoke assets
invoke coffee
create app/assets/javascripts/say.coffee
invoke scss
create app/assets/stylesheets/say.scss
edit app/controllers/say_controller.rb
class SayController < ApplicationController
def hello
end
def goodbye
end
end
Restart the server.
Attempt to fetch the file - note that it is missing
get /say/hello
Say#hello
Find me in app/views/say/hello.html.erb
Replace file with a simple hello world
edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>
This time it works!
get /say/hello
Hello from Rails!
Add a simple expression
edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>
<p>
It is now <%= Time.now %>
</p>
get /say/hello
Hello from Rails!
It is now 2017-11-13 09:40:34 -0500
Evaluate the expression in the controller.
edit app/controllers/say_controller.rb
class SayController < ApplicationController
def hello
@time = Time.now
end
def goodbye
end
end
Reference the result in the view.
edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>
<p>
It is now <%= @time %>
</p>
get /say/hello
Hello from Rails!
It is now 2017-11-13 09:40:34 -0500
Replace the goodbye template
edit app/views/say/goodbye.html.erb
<h1>Goodbye!</h1>
<p>
It was nice having you here.
</p>
get /say/goodbye
Goodbye!
It was nice having you here.
Add a link from the hello page to the goodbye page
edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>
<p>
It is now <%= @time %>
</p>
<p>
Time to say
<%= link_to "Goodbye", say_goodbye_path %>!
</p>
get /say/hello
Hello from Rails!
It is now 2017-11-13 09:40:34 -0500
Time to say
Goodbye!
Add a link back to the hello page
edit app/views/say/goodbye.html.erb
<h1>Goodbye!</h1>
<p>
It was nice having you here.
</p>
<p>
Say <%= link_to "Hello", say_hello_path %> again.
</p>
get /say/goodbye
Goodbye!
It was nice having you here.
Say Hello again.
Intentionally introduce a typo in the code
edit app/controllers/say_controller.rb
class SayController < ApplicationController
def hello
@time = Time.know
end
def goodbye
end
end
get /say/hello
HTTP Response Code: 500
NoMethodError
in SayController#hello
undefined method `know' for Time:Class
Did you mean? now
Extracted source (around line #4):
2
3
4
5
6
7
|
def hello
#START_HIGHLIGHT
@time = Time.know
#END_HIGHLIGHT
end
|
Extracted source (around line #6):
4
5
6
7
8
9
|
module BasicImplicitRender # :nodoc:
def send_action(method, *args)
super.tap { default_render unless performed? }
end
def default_render(*args)
|
Extracted source (around line #194):
192
193
194
195
196
197
|
# which is *not* necessarily the same as the action name.
def process_action(method_name, *args)
send_action(method_name, *args)
end
# Actually call the method associated with the action. Override
|
Extracted source (around line #30):
28
29
30
31
32
33
|
def process_action(*) #:nodoc:
self.formats = request.formats.map(&:ref).compact
super
end
# Check for double render errors and set the content_type after rendering.
|
Extracted source (around line #42):
40
41
42
43
44
45
|
def process_action(*args)
run_callbacks(:process_action) do
super
end
end
|
Extracted source (around line #132):
130
131
132
133
134
135
|
if next_sequence.final?
next_sequence.invoke_before(env)
env.value = !env.halted && (!block_given? || yield)
next_sequence.invoke_after(env)
env.value
else
|
Extracted source (around line #41):
39
40
41
42
43
44
|
# <tt>process_action</tt> callbacks around the normal behavior.
def process_action(*args)
run_callbacks(:process_action) do
super
end
end
|
Extracted source (around line #22):
20
21
22
23
24
25
|
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 #34):
32
33
34
35
36
37
|
ActiveSupport::Notifications.instrument("process_action.action_controller", raw_payload) do |payload|
begin
result = super
payload[:status] = response.status
result
ensure
|
Extracted source (around line #168):
166
167
168
169
170
171
|
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 #23):
21
22
23
24
25
26
|
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 #168):
166
167
168
169
170
171
|
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 #32):
30
31
32
33
34
35
|
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 #256):
254
255
256
257
258
259
|
request.filtered_parameters.merge! wrapped_filtered_hash
end
super
end
private
|
Extracted source (around line #24):
22
23
24
25
26
27
|
# 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 #134):
132
133
134
135
136
137
|
@_response_body = nil
process_action(action_name, *args)
end
# Delegates to the class' ::controller_path
|
Extracted source (around line #32):
30
31
32
33
34
35
|
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 #191):
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190
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192
193
194
|
set_request!(request)
set_response!(response)
process(name)
request.commit_flash
to_a
end
|
Extracted source (around line #254):
252
253
254
255
256
257
|
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 #52):
50
51
52
53
54
55
|
def dispatch(controller, action, req, res)
controller.dispatch(action, req, res)
end
end
|
Extracted source (around line #34):
32
33
34
35
36
37
|
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 #52):
50
51
52
53
54
55
|
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 #35):
33
34
35
36
37
38
|
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 #35):
33
34
35
36
37
38
|
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 #830):
828
829
830
831
832
833
|
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 #232):
230
231
232
233
234
235
|
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 #226):
224
225
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227
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229
|
def call(env)
context(env)
end
def context(env, app=@app)
|
Extracted source (around line #663):
661
662
663
664
665
666
|
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 #558):
556
557
558
559
560
561
|
@last_check = mtime
end
@app.call(env)
end
private
|
Extracted source (around line #28):
26
27
28
29
30
31
|
result = run_callbacks :call do
begin
@app.call(env)
rescue => error
end
end
|
Extracted source (around line #98):
96
97
98
99
100
101
|
if callbacks.empty?
yield if block_given?
else
env = Filters::Environment.new(self, false, nil)
next_sequence = callbacks.compile
|
Extracted source (around line #26):
24
25
26
27
28
29
|
def call(env)
error = nil
result = run_callbacks :call do
begin
@app.call(env)
rescue => error
|
Extracted source (around line #14):
12
13
14
15
16
17
|
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 #61):
59
60
61
62
63
64
|
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 #137):
135
136
137
138
139
140
|
def call_app(env)
@app.call(env)
rescue => e
throw :app_exception, e
end
|
Extracted source (around line #30):
28
29
30
31
32
33
|
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 #20):
18
19
20
21
22
23
|
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 #20):
18
19
20
21
22
23
|
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 #33):
31
32
33
34
35
36
|
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 #38):
36
37
38
39
40
41
|
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 #26):
24
25
26
27
28
29
|
if logger.respond_to?(:tagged)
logger.tagged(compute_tags(request)) { call_app(request, env) }
else
call_app(request, env)
end
|
Extracted source (around line #71):
69
70
71
72
73
74
|
def tagged(*tags)
formatter.tagged(*tags) { yield self }
end
def flush
|
Extracted source (around line #28):
26
27
28
29
30
31
|
def tagged(*tags)
new_tags = push_tags(*tags)
yield self
ensure
pop_tags(new_tags.size)
end
|
Extracted source (around line #71):
69
70
71
72
73
74
|
def tagged(*tags)
formatter.tagged(*tags) { yield self }
end
def flush
|
Extracted source (around line #26):
24
25
26
27
28
29
|
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 #81):
79
80
81
82
83
84
|
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 #27):
25
26
27
28
29
30
|
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
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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 #29):
27
28
29
30
31
32
|
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 #14):
12
13
14
15
16
17
|
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 #127):
125
126
127
128
129
130
|
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 #524):
522
523
524
525
526
527
|
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 #225):
223
224
225
226
227
228
|
def call(env)
env[Const::PUMA_CONFIG] = @config
@app.call(env)
end
end
|
Extracted source (around line #605):
603
604
605
606
607
608
|
begin
begin
status, headers, res_body = @app.call(env)
return :async if req.hijacked
|
Extracted source (around line #437):
435
436
437
438
439
440
|
while true
case handle_request(client, buffer)
when false
return
when :async
|
Extracted source (around line #301):
299
300
301
302
303
304
|
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/demo1
Request
Parameters:
None
_csrf_token: "gXqSGN3ZTBjLslWC+/hZacUW08Zr8hP2SwRLgKx+q1k="
session_id: "d3f94034f559eab14125639b5fc95242"
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
Intentionally introduce a typo in a URL
get /say/hullo
HTTP Response Code: 404
No route matches [GET] "/say/hullo"
Rails.root: /home/rubys/git/awdwr/edition4/work/demo1
Routes
Routes match in priority from top to bottom
Request
Parameters:
None
_csrf_token: "gXqSGN3ZTBjLslWC+/hZacUW08Zr8hP2SwRLgKx+q1k="
session_id: "d3f94034f559eab14125639b5fc95242"
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
6.1 Iteration A1: Creating the Products Maintenance Application
Table of Contents