Using GServer in Ruby

By: James Edward Gray II Viewed: 153192 times  Printer Friendly Format    


GServer implements a generic server, featuring thread pool management, simple logging, and multi-server management. See xmlrpc/httpserver.rb in the Ruby standard library for an example of GServer in action.

Any kind of application-level server can be implemented using this class. It accepts multiple simultaneous connections from clients, up to an optional maximum number. Several services (i.e. one service per TCP port) can be run simultaneously, and stopped at any time through the class method GServer.stop(port). All the threading issues are handled, saving you the effort. All events are optionally logged, but you can provide your own event handlers if you wish.

Example

Using GServer is simple. Below we implement a simple time server, run it, query it, and shut it down. Try this code in irb:

  require 'gserver'

  #
  # A server that returns the time in seconds since 1970.
  #
  class TimeServer < GServer
    def initialize(port=10001, *args)
      super(port, *args)
    end
    def serve(io)
      io.puts(Time.now.to_i)
    end
  end

  # Run the server with logging enabled (it's a separate thread).
  server = TimeServer.new
  server.audit = true                  # Turn logging on.
  server.start

  # *** Now point your browser to http://localhost:10001 to see it working ***

  # See if it's still running.
  GServer.in_service?(10001)           # -> true
  server.stopped?                      # -> false

  # Shut the server down gracefully.
  server.shutdown

  # Alternatively, stop it immediately.
  GServer.stop(10001)
  # or, of course, "server.stop".

All the business of accepting connections and exception handling is taken care of. All we have to do is implement the method that actually serves the client.

Advanced

As the example above shows, the way to use GServer is to subclass it to create a specific server, overriding the serve method. You can override other methods as well if you wish, perhaps to collect statistics, or emit more detailed logging.

  connecting
  disconnecting
  starting
  stopping

The above methods are only called if auditing is enabled.

You can also override log and error if, for example, you wish to use a more sophisticated logging system.



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