HTTP dev server with ruby webrick

httpd

#!/usr/bin/env ruby

require 'optparse'
require 'webrick'

# Add additional MIME types here
WEBrick::Config::HTTP[:MimeTypes].update({
  'wasm' => 'application/wasm'
})

# Defaults
ROOT_DEFAULT = './'
PORT_DEFAULT = 8000

options = {
  root: ROOT_DEFAULT,
  port: PORT_DEFAULT
}

# Process ENV
options[:root] = ENV['ROOT'] if ENV['ROOT']
options[:port] = ENV['PORT'].to_i if ENV['PORT']

# Prepare ARGV parser
parser = OptionParser.new
parser.version = '0.1.0'
parser.on('-r', '--root DIR', String, "root directory (default = #{ROOT_DEFAULT})") do |v|
  options[:root] = v
end
parser.on('-p', '--port NUM', Integer, "port number (default = #{PORT_DEFAULT})") do |v|
  if v < 0 || v > 65535
    raise "Invalid port number: #{v} (must be within the range of 0 to 65535)"
  end
  options[:port] = v
end

# Run
begin
  parser.parse! ARGV
  server = WEBrick::HTTPServer.new({
    DocumentRoot: options[:root],
    Port: options[:port]
  })
  server.start
rescue
  STDERR.puts $!
end