A "fake" HTTP server for local development or testing of HTTP clients

fake_server.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

require 'webrick'

class FakeServlet < WEBrick::HTTPServlet::AbstractServlet
  RESPONSE_BODY = "Success\n"
  TEXT_PLAIN = 'text/plain'

  def do_GET(_request, response)
    # query hash is accessible via request.query
    # request path is accessible via request.path

    response.status = 200
    response.content_type = TEXT_PLAIN
    response.body = RESPONSE_BODY
  end
end

class FakeServer
  DEFAULT_PORT = 80

  def initialize(port = nil)
    port ||= DEFAULT_PORT
    @server = WEBrick::HTTPServer.new(Port: port)
    @server.mount '/', FakeServlet
    @server.start
  end
end

port = ARGV[0].to_i unless ARGV.empty?
FakeServer.new(port)