Updates oven page automatically when cookie is ready

- Puts cookie retrieval markup in separate partial
- Adds SSE support on ovens controller
- Adds SSE listener on the client side

Issue: #5

app/assets/javascripts/ovens/show.js

@@ -0,0 +1,11 @@
+document.addEventListener('DOMContentLoaded', () => {
+  let cookieStatus, eventSource;
+
+  cookieStatus = document.querySelector('.cookie-status');
+  eventSource = new EventSource('/ovens/2/progress');
+
+  eventSource.addEventListener('message', event => {
+    cookieStatus.innerHTML = event.data;
+    eventSource.close();
+  });
+})

app/controllers/ovens_controller.rb

@@ -1,4 +1,7 @@
 class OvensController < ApplicationController
+  include ActionController::Live
+  SSE_RETRY_TIME = 5000.freeze
+
   before_action :authenticate_user!
 
   def index
@@ -16,4 +19,19 @@ def empty
     end
     redirect_to @oven, alert: 'Oven emptied!'
   end
+
+  def progress
+    @oven = Oven.find(params[:id])
+    sse = SSE.new(response.stream)
+    response.headers['Content-Type'] = 'text/event-stream'
+
+    return sse.close if @oven.cookie.ready? == false
+
+    template = render_to_string(partial: 'cookie.ready', formats: [:html])
+    sse.write(template, retry: SSE_RETRY_TIME)
+  rescue IOError
+    Rails.Logger.error(IOError)
+  ensure
+    sse.close if sse.present?
+  end
 end

app/views/ovens/_cookie.ready.html.haml

@@ -0,0 +1,2 @@
+(Your Cookie is Ready)
+= button_to "Retrieve Cookie", empty_oven_path, class: 'button tiny'

app/views/ovens/show.html.haml

@@ -4,12 +4,13 @@
   Cookie in oven:
   - if @oven.cookie
     1 cookie with #{show_cookie_filling(@oven.cookie)}
-    - if @oven.cookie.ready?
-      (Your Cookie is Ready)
-      = button_to "Retrieve Cookie", empty_oven_path, class: 'button tiny'
+    .cookie-status
+      - if @oven.cookie.ready?
+        = render 'ovens/cookie.ready'
   - else
     None
 
 %br
 
 = link_to "Prepare Cookie", new_oven_cookies_path(@oven), class: 'button'
+= javascript_include_tag "ovens/show"

config/environments/development.rb

@@ -6,6 +6,8 @@
   # since you don't have to restart the web server when you make code changes.
   config.cache_classes = false
 
+  config.allow_concurrency = true
+
   # Do not eager load code on boot.
   config.eager_load = false
 

config/environments/production.rb

@@ -4,6 +4,8 @@
   # Code is not reloaded between requests.
   config.cache_classes = true
 
+  config.allow_concurrency = true
+
   # Eager load code on boot. This eager loads most of Rails and
   # your application in memory, allowing both threaded web servers
   # and those relying on copy on write to perform better.

config/environments/test.rb

@@ -7,6 +7,8 @@
   # and recreated between test runs. Don't rely on the data there!
   config.cache_classes = true
 
+  config.allow_concurrency = true
+
   # Do not eager load code on boot. This avoids loading your whole application
   # just for the purpose of running a single test. If you are using a tool that
   # preloads Rails for running tests, you may have to set it to true.

config/initializers/assets.rb

@@ -12,4 +12,4 @@
 # application.js, application.css, and all non-JS/CSS in the app/assets
 # folder are already added.
 # Rails.application.config.assets.precompile += %w[admin.js admin.css]
-Rails.application.config.assets.precompile += %w[vendor/modernizr]
+Rails.application.config.assets.precompile += %w[vendor/modernizr ovens/show]

config/routes.rb

@@ -12,6 +12,7 @@
   resources :ovens do
     resource :cookies
     member do
+      get :progress
       post :empty
     end
   end