Add Stack Exchange onebox

lib/oneboxer/stack_exchange_onebox.rb

@@ -0,0 +1,46 @@
+require_dependency 'oneboxer/handlebars_onebox'
+
+module Oneboxer
+  class StackExchangeOnebox < HandlebarsOnebox
+    DOMAINS = [
+      'stackexchange',
+      'stackoverflow',
+      'superuser',
+      'serverfault',
+      'askubuntu'
+    ]
+
+    # http://rubular.com/r/V3T0I1VTPn
+    REGEX =
+      /^http:\/\/(?:(?<subdomain>\w*)\.)?(?<domain>#{DOMAINS.join('|')})\.com\/(?:questions|q)\/(?<question>\d*)/
+
+    matcher REGEX
+    favicon 'stackexchange.png'
+
+    def translate_url
+      @url.match(REGEX) do |match|
+        site = if match[:domain] == 'stackexchange'
+          match[:subdomain]
+        else
+          match[:domain]
+        end
+
+        ["http://api.stackexchange.com/2.1/",
+         "questions/#{match[:question]}",
+         "?site=#{site}"
+        ].join
+      end
+    end
+
+    def parse(data)
+      result = JSON.parse(data)['items'].first
+
+      result['creation_date'] =
+        Time.at(result['creation_date'].to_i).strftime("%I:%M%p - %d %b %y")
+
+      result['tags'] = result['tags'].take(4).join(', ')
+
+      result
+    end
+  end
+end