Wrote Jekyll tag that renders base64 codes of images fetched from the web

Author: GSI2013

README.textile

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+h1. Jekyll Image Encode
+
+This Jekyll plugin fetches images from the web and renders their according base64 codes.
+
+Be sure to know your reasons when using it.
+
+
+h2. Installation
+
+Set the variable @PATH_TO_JEKYLL_SITE@ correctly and run these commands accordingly:
+
+pre. echo "gem 'jekyll_image_encode'" >> $PATH_TO_JEKYLL_SITE/Gemfile
+bundle
+echo "require 'jekyll_image_encode'" >> $PATH_TO_JEKYLL_SITE/_plugins/ext.rb
+
+
+h2. Usage
+
+In the source attribute of an HTML *img* element, call the *base64-tag* providing the image URL as the only parameter:
+
+pre. <img src="{% base64 http://example.org/image.png %}" />

jekyll_image_encode.gemspec

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+Gem::Specification.new do |s|
+  s.name        = 'jekyll_image_encode'
+  s.version     = '0.0.1'
+  s.date        = '2013-08-10'
+  s.summary     = "Jekyll Image Encode"
+  s.description = "Jekyll tag that renders base64 codes of images fetched from the web"
+  s.authors     = ["GSI"]
+  s.email       = '[email protected]'
+  s.files       = Dir.glob('lib/**/*') # `git ls-files`.split($/)
+  s.homepage    = 'https://github.com/GSI/' + s.name
+  s.license     = 'MIT'
+end

lib/jekyll_image_encode.rb

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+module ImageEncodeCache
+  @@cached_base64_codes = Hash.new
+  
+  def cached_base64_codes
+    @@cached_base64_codes
+  end
+  
+  def cached_base64_codes= val
+    @@cached_base64_codes = val
+  end
+end
+
+module Jekyll
+  module Tags
+    class ImageEncodeTag < Liquid::Tag
+      include ImageEncodeCache
+          
+      def initialize(tag_name, url, options)
+        @url = url.strip
+        super
+      end
+
+      def render(context)
+        encode_image
+      end
+      
+      def encode_image
+        require 'open-uri'
+        require 'base64'
+        
+        encoded_image = ''
+
+        if self.cached_base64_codes.has_key? @url
+          encoded_image = self.cached_base64_codes[@url]
+        else
+          # p "Caching #{@url} as local base64 string ..."
+          open(@url) do |image|
+            encoded_image = Base64.encode64(image.read)
+          end
+          self.cached_base64_codes.merge!(@url => encoded_image)
+        end
+        
+        "data:image;base64, #{encoded_image}"
+      end
+    end
+  end
+end
+
+Liquid::Template.register_tag('base64', Jekyll::Tags::ImageEncodeTag)