Use XMLHttpRequest to load Nurikabe game data

nikoli.rb

@@ -2,13 +2,17 @@
 
 require 'sinatra'
 require 'sinatra/content_for'
+require 'sinatra/json'
 
+require 'yaml'
 require 'coffee-script'
 require 'slim'
 require 'sass'
 
 GAMES = %i{hitori nurikabe sudoku}
 
+set :data_folder, File.expand_path('./data')
+
 get('/application.css') { scss :application }
 get('/application.js') { coffee :application }
 
@@ -18,3 +22,10 @@ GAMES.each do |game|
   get("/#{game}") { slim game }
   get("/#{game}.js") { coffee game }
 end
+
+get "/data/:game/:file.json" do |game, file|
+  data_file = File.join(settings.data_folder, game, "#{file}.yml")
+  halt(404) unless File.exist?(data_file)
+
+  json YAML.load_file(data_file).sample
+end

views/nurikabe.slim

@@ -6,8 +6,12 @@ h1 Nurikabe
 script type="text/javascript" src="/nurikabe.js"
 javascript:
   document.addEventListener("DOMContentLoaded", function() {
-    var game = JSON.parse("[[4,-1,-1,0,2],[0,-1,2,-1,-1],[0,-1,0,-1,3],[0,-1,-1,-1,0],[-1,-1,1,-1,0]]");
-
     nurikabe = new Nurikabe(document.getElementById('board'));
-    nurikabe.generate(game);
+
+    xmlhttp = new XMLHttpRequest();
+    xmlhttp.open("GET", "#{url('/data/nurikabe/5x5.json')}");
+
+    xmlhttp.addEventListener('load', function(evt) {
+      nurikabe.generate(JSON.parse(evt.target.responseText)) })
+    xmlhttp.send();
   });