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A Liquid tag for Jekyll sites that allows embedding Gists and showing code for non-JavaScript enabled browsers and readers.
require 'cgi'
require 'digest/md5'
require 'net/https'
require 'uri'
module Jekyll
class GistTag < Liquid::Tag
def initialize(tag_name, text, token)
super
@text = text
@cache_disabled = false
@cache_folder = File.expand_path "../_gist_cache", File.dirname(__FILE__)
end
def render(context)
if parts = @text.match(/([\d]*) (.*)/)
gist, file = parts[1].strip, parts[2].strip
script_url = script_url_for gist, file
code = get_cached_gist(gist, file) || get_gist_from_web(gist, file)
html_output_for script_url, code
else
""
end
end
def html_output_for(script_url, code)
code = CGI.escapeHTML code
"<script src='#{script_url}'></script><noscript><pre><code>#{code}</code></pre></noscript>"
end
def script_url_for(gist_id, filename)
"https://gist.github.com/#{gist_id}.js?file=#{filename}"
end
def get_gist_url_for(gist, file)
"https://gist.github.com/raw/#{gist}/#{file}"
end
def cache(gist, file, data)
cache_file = get_cache_file_for gist, file
File.open(cache_file, "w") do |io|
io.write data
end
end
def get_cached_gist(gist, file)
return nil if @cache_disabled
cache_file = get_cache_file_for gist, file
File.read cache_file if File.exist? cache_file
end
def get_cache_file_for(gist, file)
bad_chars = /[^a-zA-Z0-9\-_.]/
gist = gist.gsub bad_chars, ''
file = file.gsub bad_chars, ''
md5 = Digest::MD5.hexdigest "#{gist}-#{file}"
File.join @cache_folder, "#{gist}-#{file}-#{md5}.cache"
end
def get_gist_from_web(gist, file)
gist_url = get_gist_url_for gist, file
raw_uri = URI.parse gist_url
https = Net::HTTP.new raw_uri.host, raw_uri.port
https.use_ssl = true
https.verify_mode = OpenSSL::SSL::VERIFY_NONE
request = Net::HTTP::Get.new raw_uri.request_uri
data = https.request request
data = data.body
cache gist, file, data unless @cache_disabled
data
end
end
class GistTagNoCache < GistTag
def initialize(tag_name, text, token)
super
@cache_disabled = true
end
end
end
Liquid::Template.register_tag('gist', Jekyll::GistTag)
Liquid::Template.register_tag('gistnocache', Jekyll::GistTagNoCache)
@asmega
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asmega commented Jul 31, 2011

+1

@CoffeeAndCode
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CoffeeAndCode commented Jan 8, 2013

In case anyone stumbles here wondering why the noscript portion gets butchered, I think it's from the Markdown parser. (sorry, not really sure)

But you can fix the output by removing the noscript tags and just hiding the pre with javascript instead. That why the page will still show the code if javascript is off, say in RSS feed content for example.

@benclark
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benclark commented Jan 20, 2013

The Markdown parser bug appears to be fixed by adding a newline character between the </script> and <noscript>:

<script src='#{script_url}'></script>\n<noscript><pre><code>#{code}</code></pre></noscript>

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