TCPServerDeluxe, simple tcp socket server that responds to http requests for an executable

tcpserverdeluxe.rb

class TcpServerDeluxe

require 'socket'

"""
Ruby 2.1.0
Description:
TCP Server, runs from command line or upstart.  Requires two agruments.
Argument #1 is server port, Argument #2 is executable path
200 will return stdout of executable (cgi)
405 error if not using HTTP GET method
404 error if client requests anything besides GET /
500 error if executable returns non-zero exitstatus
"""

"""
Running:
Start server with by executing:

ruby /path/to/tcpserverdeluxe.rb <port_number> </path/to/executable> &

tcpserverdeluxe.rb will run in the background.

Or manage with upstart, example:

console log
respawn

script
  exec ruby /path/to/tcpserverdeluxe.rb $1 $2 >> /var/log/tcpserverdeluxe.log 2>&1
end script
"""

  def self.success_responses_header
    success_headers = [['HTTP/1.1 200',
                     'Content-Type: text/plain \r\n',
                     'Status 200 \r\n'].join("\r\n")]
    return success_headers
  end

  def self.failure_responses_header
    failure_headers = [['HTTP/1.1 405',
                     'Content-Type: text/plain \r\n',
                     'Status 405 \r\n'].join("\r\n"),
                     ['HTTP/1.1 404',
                     'Content-Type: text/plain \r\n',
                     'Status 404 \r\n'].join("\r\n"),
                     ['HTTP/1.1 500' ,
                     'Content-Type: text/plain \r\n',
                     'Status 500 \r\n'].join("\r\n")
                     ]
    return failure_headers
  end

  def self.body_responses
    resp = ["405 Error",
            "404 Error",
            "500 Error",]
    return resp
  end

  def self.client_response(client, status, resp)
    client.write status
    client.puts "\r\n\r\n", resp
    client.close
  end

  def self.execute_cgi(executable_file)
    executable = executable_file
    cgi = IO.popen(executable, "r")
    exitstatus = $?.to_i
    return exitstatus, cgi.read
  end

  def self.init_server(port)
    read_chunk = 1024 * 4
    server = TCPServer.open(port)
    return read_chunk, server
  end

  def self.run_server(port, executable)
    read_chunk, server = init_server(port)
    loop {
      begin
        client = server.accept
        http_data = client.readpartial(read_chunk)
      rescue EOFError
        retry
      end
      case http_data.lines.first
      when /^(OPTIONS|HEAD|POST|PUT|DELETE|TRACE|CONNECT).*/
       resp = body_responses[0]
       failure_headers = failure_responses_header[0]
       client_response(client, failure_headers, resp)
      when /^GET \/[a-zA-Z0-9]/
          resp = body_responses[1]
          failure_headers = failure_responses_header[1]
          client_response(client, failure_headers, resp)
      when /^GET \/./
        exitstatus, cgi = execute_cgi(executable)
	if exitstatus == 0 then
          success_headers = success_responses_header[0]
          client_response(client, success_headers, cgi)
	else
          resp = body_responses[2]
          failure_headers = failure_responses_header[2]
          client_response(client, failure_headers, resp)
	end
      else
       resp = body_responses[0]
       failure_headers = failure_responses_header[0]
       client_response(client, failure_headers, resp)
      end
    }
   end
end

TcpServerDeluxe.run_server(ARGV[0], ARGV[1])  if __FILE__==$0