Rack-based Local YARD Server

config.ru

require 'rubygems'
require 'yard'

libs = {}
gems = {}
base = ENV['GEM_PATH'].split(':')[1][%r{^.+(?=/.+@global$)}] rescue nil

if base
  Gem.paths = {
    'GEM_PATH' => Dir["#{base}/ruby-*"].join(':'),
    'GEM_HOME' => ENV['GEM_HOME']
  }

  Gem.source_index.find_name('').each do |spec|
    libs[spec.name] ||= []
    libs[spec.name] << YARD::Server::LibraryVersion.new(spec.name, spec.version.to_s, nil, :gem)
  end
end

run YARD::Server::RackAdapter.new(libs)

For all gems available, use:

require 'rubygems'
require 'yard'

libs = {}
Gem.source_index.find_name('').each do |spec|
  libs[spec.name] ||= []
  libs[spec.name] << YARD::Server::LibraryVersion.new(spec.name, spec.version.to_s, nil, :ge
end

run YARD::Server::RackAdapter.new(libs)