run_local_webserver.rb

#!/usr/bin/env ruby

require 'webrick'
require 'open-uri'
require 'yaml'

class SsiHandler < WEBrick::HTTPServlet::FileHandler
  def initialize(server, root, options = {})
    super
    @host = options[:Host]
    @enabled = options[:Enabled]
  end

  def service(req, res)
    super
    return unless @enabled && res.body.path.include?('.html')

    body = res.body.read

    body.scan(/\<!--#include virtual=".*" --\>/).each do |match|
      sub_start = match.index('"') + 1
      sub_end = match.index('"', sub_start)
      ssi_file = match[sub_start, sub_end - sub_start]
      ssi_content = open("#{@host}#{ssi_file}").read
      body.insert(
        body.index(match) + match.length,
        ssi_content.gsub(%r{href="/}, "href=\"#{@host}/").gsub(%r{src="/}, "src=\"#{@host}/")
      )
    end

    res.body = body
    res.content_length = body.length
  end
end

def start_webrick(config = {})
  local_config = YAML.load_file('config/local_webserver_config.yaml')

  if config[:Port].nil?
    config.update(Port: local_config['webserver']['local']['port'])
  end
  server = WEBrick::HTTPServer.new(config)

  local_config['webserver']['local']['mount_dirs'].each do |d|
    puts "Mounting #{d['file_path']} at #{d['server_path']}"
    server.mount(
      d['server_path'],
      SsiHandler,
      d['file_path'],
      FancyIndexing: true,
      Host: local_config['webserver']['ssi']['host'],
      Enabled: local_config['webserver']['ssi']['enabled']
    )
  end

  proxed_paths = {}
  proxies = config[:Proxies] || 'search_proxies'
  local_config['webserver']['local'][proxies].each do |search_proxy|
    next unless search_proxy['enabled']

    url = "http://#{search_proxy['remote_host']}:#{search_proxy['port']}#{search_proxy['path']}"
    proxed_paths[url] = search_proxy['server_path']
    server.unmount search_proxy['server_path']
    server.mount_proc search_proxy['server_path'] do |req, res|
      search_url = "#{url}?#{req.query_string}"
      res.status = 200
      res['Content-Type'] = search_proxy['content_type']
      res['Access-Control-Allow-Origin'] = '*'  # may as well throw in a CORS header...
      res['Access-Control-Allow-Methods'] = '*'  # may as well throw in a CORS header...
      res['Access-Control-Allow-Headers'] = '*'  # may as well throw in a CORS header...
      res['Access-Control-Request-Method'] = '*'  # may as well throw in a CORS header...

      # It's hokey, but it seems to work: after pulling the content down from
      # the remote server, replace any paths that are proxied by this server.
      puts "search_url = #{search_url}"
      body = open(search_url).read
      proxed_paths.each do |remote_path, local_path|
        body = body.gsub(remote_path, "http://#{req.host}:#{req.port}#{local_path}")
      end

      res.body = body
    end
  end

  yield server if block_given?

  %w(INT TERM).each do |signal|
    trap(signal) { server.shutdown }
  end

  server.start
end

start_webrick(DocumentRoot: Dir.pwd, Port: ARGV[0], Proxies: ARGV[1])