Ruby TCPServer有时无法工作

Question

I've implemented a very simple kind of server in Ruby, using TCPServer . I have a Server class with serve method:

def serve
    # Do the actual serving in a child process
    @pid = fork do
      # Trap signal sent by #stop or by pressing ^C
      Signal.trap('INT') { exit }

      # Create a new server on port 2835 (1 ounce = 28.35 grams)
      server = TCPServer.new('localhost', 2835)
      @logger.info 'Listening on http://localhost:2835...'

      loop do
        socket = server.accept
        request_line = socket.gets

        @logger.info "* #{request_line}"

        socket.print "message"

        socket.close
      end
    end
  end

and a stop method:

def stop
    @logger.info 'Shutting down'
    Process.kill('INT', @pid)
    Process.wait
    @pid = nil
end

I run my server from the command line, using:

if __FILE__ == $0
  server = Server.new
  server.logger = Logger.new(STDOUT)
  server.logger.formatter = proc { |severity, datetime, progname, msg| "#{msg}\n" }
  begin
    server.serve
    Process.wait
  rescue Interrupt
    server.stop
  end
end

The problem is that, sometimes, when I do ruby server.rb from my terminal, the server starts, but when I try to make a request on localhost:2835 , it fails. Only after several requests it starts serving some pages. In other cases, I need to stop/start the server again for it to properly serve pages. Why is this happening? Am I doing something wrong? I find this very weird...

The same things applies to my specs: I have some specs defined, and some Capybara specs. Before each test I create a server and start it and after each test I stop the server. And the problem persists: tests sometimes pass, sometimes fail because the requested page could not be found.

Is there something fishy going on with my fork ing?

Would appreciate any answer because I have no more place to look...

Answer 1

Your code is not an HTTP server. It is a TCP server that sends the string "message" over the socket after receiving a newline.

The reason that your code isn't a valid HTTP server is that it doesn't conform to the HTTP protocol . One of the many requirements of the HTTP protocol is that the server respond with a message of the form

HTTP/1.1 <code> <reason>

Where <code> is a number and <reason> is a human-readable "status", like "OK" or "Server Error" or something along those lines. The string message obviously does not conform to this requirement.

Here is a simple introduction to how you might build a HTTP server in ruby: https://practicingruby.com/articles/implementing-an-http-file-server