blog/plugins/category_generator.rb

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# encoding: utf-8
#
# Jekyll category page generator.
# http://recursive-design.com/projects/jekyll-plugins/
#
# Version: 0.1.4 (201101061053)
#
# Copyright (c) 2010 Dave Perrett, http://recursive-design.com/
# Licensed under the MIT license (http://www.opensource.org/licenses/mit-license.php)
#
# A generator that creates category pages for jekyll sites.
#
# Included filters :
# - category_links: Outputs the list of categories as comma-separated <a> links.
# - date_to_html_string: Outputs the post.date as formatted html, with hooks for CSS styling.
#
# Available _config.yml settings :
# - category_dir: The subfolder to build category pages in (default is 'categories').
# - category_title_prefix: The string used before the category name in the page title (default is
# 'Category: ').
module Jekyll
# The CategoryIndex class creates a single category page for the specified category.
class CategoryIndex < Page
# Initializes a new CategoryIndex.
#
# +base+ is the String path to the <source>.
# +category_dir+ is the String path between <source> and the category folder.
# +category+ is the category currently being processed.
def initialize(site, base, category_dir, category)
@site = site
@base = base
@dir = category_dir
@name = 'index.html'
self.process(@name)
# Read the YAML data from the layout page.
self.read_yaml(File.join(base, '_layouts'), 'category_index.html')
self.data['category'] = category
# Set the title for this page.
title_prefix = site.config['category_title_prefix'] || 'Category: '
self.data['title'] = "#{title_prefix}#{category}"
# Set the meta-description for this page.
meta_description_prefix = site.config['category_meta_description_prefix'] || 'Category: '
self.data['description'] = "#{meta_description_prefix}#{category}"
end
end
# The Site class is a built-in Jekyll class with access to global site config information.
class Site
# Creates an instance of CategoryIndex for each category page, renders it, and
# writes the output to a file.
#
# +category_dir+ is the String path to the category folder.
# +category+ is the category currently being processed.
def write_category_index(category_dir, category)
index = CategoryIndex.new(self, self.source, category_dir, category)
index.render(self.layouts, site_payload)
index.write(self.dest)
# Record the fact that this page has been added, otherwise Site::cleanup will remove it.
self.pages << index
end
# Loops through the list of category pages and processes each one.
def write_category_indexes
if self.layouts.key? 'category_index'
dir = self.config['category_dir'] || 'categories'
self.categories.keys.each do |category|
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self.write_category_index(File.join(dir, category.gsub(/_|\P{Word}/, '-').gsub(/-{2,}/, '-').downcase), category)
end
# Throw an exception if the layout couldn't be found.
else
throw "No 'category_index' layout found."
end
end
end
# Jekyll hook - the generate method is called by jekyll, and generates all of the category pages.
class GenerateCategories < Generator
safe true
priority :low
def generate(site)
site.write_category_indexes
end
end
# Adds some extra filters used during the category creation process.
module Filters
# Outputs a list of categories as comma-separated <a> links. This is used
# to output the category list for each post on a category page.
#
# +categories+ is the list of categories to format.
#
# Returns string
#
def category_links(categories)
dir = @context.registers[:site].config['category_dir']
categories = categories.sort!.map do |item|
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"<a class='category' href='/#{dir}/#{item.gsub(/_|\P{Word}/, '-').gsub(/-{2,}/, '-').downcase}/'>#{item}</a>"
end
case categories.length
when 0
""
when 1
categories[0].to_s
else
"#{categories[0...-1].join(', ')}, #{categories[-1]}"
end
end
# Outputs the post.date as formatted html, with hooks for CSS styling.
#
# +date+ is the date object to format as HTML.
#
# Returns string
def date_to_html_string(date)
result = '<span class="month">' + date.strftime('%b').upcase + '</span> '
result += date.strftime('<span class="day">%d</span> ')
result += date.strftime('<span class="year">%Y</span> ')
result
end
end
end