add cacheing

cat-in-136 · cat-in-136 · commit fd35b90b1f0c · 2019-01-03T23:52:32.000+09:00
diff --git a/_layouts/default.html b/_layouts/default.html
@@ -2,12 +2,16 @@
 <html xmlns="http://www.w3.org/1999/xhtml"{% if page.vertical-writing %} class="vertical-writing-recommended"{% endif %}>
   {% include head.html %}
   <body>
+    {% renderonceusecache header.html %}
     {% include header.html %}
+    {% endrenderonceusecache %}
     <div class="page-content">
       <div class="wrapper">
         {{ content }}
       </div>
     </div>
+    {% renderonceusecache footer.html %}
     {% include footer.html %}
+    {% endrenderonceusecache %}
   </body>
 </html>
diff --git a/_plugins/render_once_use_cache.rb b/_plugins/render_once_use_cache.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+module Jekyll
+  class RenderOnceUseCacheTag < Liquid::Block
+    @@cache = {}
+
+    def initialize(tag_name, text, tokens)
+      super
+      @text = text
+    end
+
+    def render(context)
+      @@cache[@text] = super unless @@cache.include?(@text)
+      @@cache[@text]
+    end
+  end
+end
+
+Liquid::Template.register_tag('renderonceusecache', Jekyll::RenderOnceUseCacheTag)
+
