Category Hierarchy in Jekyll - ruby

Question

I've been trying to use Jekyll categories in a hierarchical fashion, i.e.
A: ['class', 'topic', 'foo']
AA: ['class', 'topic', 'foo', 'bar']
AB: ['class', 'topic', 'foo', 'baz']
AAA: ['class', 'topic', 'foo', 'bar', 'qux']
I'm trying to create a listing of all immediate subdirectories programmatically. That is, on a page with categories (A), I wish to be able to list the posts with categories (AA) and (AB), but not (AAA). Is this possible with Jekyll's vanilla structure, or should I consider using a plugin?

Answer 1

You need to use a plugin.
I've managed to make most of what you describe happen, but I'm not using categories at all, just representing a directory tree.
require 'digest/md5'
require 'open-uri'
module Jekyll
# Add accessor for directory
class Page
attr_reader :dir
end
class NavTree < Liquid::Tag
def render(context)
site = context.registers[:site]
#page_url = context.environments.first["page"]["url"]
#folder_weights = site.data['folder_weights']
#folder_icons = site.data['folder_icons']["icons"]
#nodes = {}
tree = {}
sorted_tree = {}
site.pages.each do |page|
# exclude all pages that are hidden in front-matter
if page.data["navigation"]["show"] != false
path = page.url
path = path.index('/')==0 ? path[1..-1] : path
#nodes[path] = page.data
end
end
#let's sort the pages by weight
array = []
#nodes.each do |path, data|
array.push(:path => path, :weight => data["weight"], :title => data["title"])
end
sorted_nodes = array.sort_by {|h| [-(h[:weight]||0), h[:path] ]}
sorted_nodes.each do |node|
current = tree
node[:path].split("/").inject("") do |sub_path,dir|
sub_path = File.join(sub_path, dir)
current[sub_path] ||= {}
current = current[sub_path]
sub_path
end
end
tree.each do |base, subtree|
folder_weight = #folder_weights[base]? #folder_weights[base] : 0
tree[base] = {"weight" => folder_weight, "subtree" => subtree}
end
tree_array = []
tree.each do |key, value|
tree_array.push(:base => key, :weight => value["weight"], :subtree => value["subtree"])
end
sorted_tree = tree_array.sort_by {|node| [ -(node[:weight]), node[:base] ]}
puts "generating nav tree for #{#page_url}"
files_first_traverse "", sorted_tree, 0
end
def files_first_traverse(prefix, nodes = [], depth=0)
output = ""
if depth == 0
id = 'id="nav-menu"'
end
output += "#{prefix}<ul #{id} class=\"nav nav-list\">"
nodes.each do |node|
base = node[:base]
subtree = node[:subtree]
name = base[1..-1]
if name.index('.') != nil
icon_name = #nodes[name]["icon"]
name = #nodes[name]["title"]
end
li_class = ""
if base == #page_url
li_class = "active"
if icon_name
icon_name = icon_name + " icon-white"
end
end
icon_html = "<span class=\"#{icon_name}\"></span>" unless icon_name.nil?
output += "#{prefix}<li class=#{li_class}>#{icon_html}#{name}</li>" if subtree.empty?
end
nodes.each do |node|
base = node[:base]
subtree = node[:subtree]
next if subtree.empty?
href = base
name = base[1..-1]
if name.index('.') != nil
is_parent = false
name = #nodes[name]["title"]
else
is_parent = true
href = base + '/index.html'
if name.index('/')
name = name[name.rindex('/')+1..-1]
end
end
name.gsub!(/_/,' ')
li_class = ""
if #page_url.index(base)
list_class = "collapsibleListOpen"
else
list_class = "collapsibleListClosed"
end
if href == #page_url
li_class = "active"
end
if is_parent
id = Digest::MD5.hexdigest(base)
icon_name = #folder_icons[base]
icon_html = icon_name.nil? ? "" : "<span class=\"#{icon_name}\"></span>"
li = "<li id=\"node-#{id}\" class=\"parent #{list_class}\"><div class=\"subtree-name\">#{icon_html}#{name}</div>"
else
icon_name = #nodes[name]["icon"]
if icon_name && li_class=="active"
icon_name = icon_name + " icon-white"
end
icon_html = icon_name.nil? ? "<i class=\"#{icon_name}\"></i>" : ""
li = "<li class=\"#{li_class}\">#{icon_html}#{name}</li>"
end
output += "#{prefix} #{li}"
subtree_array = []
subtree.each do |base, subtree|
subtree_array.push(:base => base, :subtree => subtree)
end
depth = depth + 1
output += files_first_traverse(prefix + ' ', subtree_array, depth)
if is_parent
output+= "</li>"
end
end
output += "#{prefix} </ul>"
output
end
end
end
Liquid::Template.register_tag("navigation", Jekyll::NavTree)
It is ugly code, but it's a start. You can see it in action on https://sendgrid.com/docs