Help with Socket (TCPServer) requested!

ruby-talk
1

Hello Team,

I need your help with sockets.

I read the PickAxe information on Socket on Apendix A. I also read an
article "Sockets programming in Ruby" By: M. Tim Jones. All the examples
provided worked within their context.
However, I am new to Socket programming and to Ruby but I am trying to
establish a simple connection between a TCPServer and a client.

Basically, I would like the server side to start and block itself waiting
for a request from a client.
The client will connect and request a service such as execute a command on
the servers side and return the output.
I am having heck of a time trying to get a simple sample program to work.
The connection is actually established, but I don't see the string that I
sent the server and I don't get anything back on the client either.

Here is my "server", please don't laugh!

require 'socket'
port = 19557
server = TCPServer.new('localhost', port)

while (session = server.accept)
  puts "Inside while..."
  puts session.to_s
  session.close
end

This is suppose to be the client:

require 'socket'
streamSock = TCPSocket.new( 'localhost', 19557 )

streamSock.send( "Hello\n" )
str = streamSock.recv( 100 )
print str
streamSock.close

I am willing to read any documentation recommended.

Thank you

2

This is suppose to be the client:

require 'socket'
streamSock = TCPSocket.new( 'localhost', 19557 )

streamSock.send( "Hello\n" )
str = streamSock.recv( 100 )
print str
streamSock.close

I am willing to read any documentation recommended.

Thank you

i understand that server should send some data to client? if that's the case then:

> while (session = server.accept)
> puts "Inside while..."
> puts session.to_s # what this line actually does? o_O probably want to do something like this:
     session.write("100 character long array")
> session.close
> end

also sing something else then recv on client end is good idea

3

Basically, I would like the server side to start and block itself waiting
for a request from a client.
The client will connect and request a service such as execute a command on
the servers side and return the output.
I am having heck of a time trying to get a simple sample program to work.
The connection is actually established, but I don't see the string that I
sent the server and I don't get anything back on the client either.

Here is my "server", please don't laugh!

require 'socket'
port = 19557
server = TCPServer.new('localhost', port)

while (session = server.accept)
puts "Inside while..."
puts session.to_s
session.close
end

This is suppose to be the client:

require 'socket'
streamSock = TCPSocket.new( 'localhost', 19557 )

streamSock.send( "Hello\n" )
str = streamSock.recv( 100 )
print str
streamSock.close

NOTE: It appears your server neither attempts to send, nor receive
any data. (For example: data = session.gets; session.puts "got it")

If your goal is to specifically learn more about the sockets
API, there are several topics you'll want to explore:

  - low-level (send/recv) vs. high-level (read/write/gets/puts) calls
    - for instance: send & recv are not guaranteed to process as many
      bytes as you ask, but will tell you how many they DID process

  - blocking vs. non-blocking io semantics

  - determining when IO is ready for reading or writing
    - select() vs. threads

However, if your goal is to just start *using* sockets without
necessarily being burdened by some of the esoteric details and
trade-offs, you might be interested in EventMachine:

http://rubyforge.org/projects/eventmachine

EventMachine not only makes network I/O easier to deal with,
it's also a high performance library. So you won't be sacrificing
speed for ease of use.

EventMachine also supports protocol helper modules that you can
use to mix-in higher level functionality than just sending and
receiving byte stream bursts.

For example, if you were writing a line-based protocol, like
POP3, SMTP, or FTP, you could start with:

  class MyProtocol < EventMachine::Protocols::LineAndTextProtocol

    def receive_line(line)
      # eventmachine LineAndTextProtcol will call your
      # receive_line method when a full line is received
      # for you to process
    end

    def send_line(line)
      line += "\n" unless line[-1] == ?\n # add EOL if not present
      send_data(line)
    end

  end

  EventMachine::start_server host, port, MyProtocol

Regards,

Bill

···

From: "Victor Reyes" <victor.reyes@gmail.com>

4

Thank you. I will try the suggestions provided.

Victor

···

On 9/9/07, Bill Kelly <billk@cts.com> wrote:

From: "Victor Reyes" <victor.reyes@gmail.com>
>
> Basically, I would like the server side to start and block itself
waiting
> for a request from a client.
> The client will connect and request a service such as execute a command
on
> the servers side and return the output.
> I am having heck of a time trying to get a simple sample program to
work.
> The connection is actually established, but I don't see the string that
I
> sent the server and I don't get anything back on the client either.
>
> Here is my "server", please don't laugh!
>
> require 'socket'
> port = 19557
> server = TCPServer.new('localhost', port)
>
> while (session = server.accept)
> puts "Inside while..."
> puts session.to_s
> session.close
> end
>
>
> This is suppose to be the client:
>
> require 'socket'
> streamSock = TCPSocket.new( 'localhost', 19557 )
>
> streamSock.send( "Hello\n" )
> str = streamSock.recv( 100 )
> print str
> streamSock.close

NOTE: It appears your server neither attempts to send, nor receive
any data. (For example: data = session.gets; session.puts "got it")

If your goal is to specifically learn more about the sockets
API, there are several topics you'll want to explore:

  - low-level (send/recv) vs. high-level (read/write/gets/puts) calls
    - for instance: send & recv are not guaranteed to process as many
      bytes as you ask, but will tell you how many they DID process

  - blocking vs. non-blocking io semantics

  - determining when IO is ready for reading or writing
    - select() vs. threads

However, if your goal is to just start *using* sockets without
necessarily being burdened by some of the esoteric details and
trade-offs, you might be interested in EventMachine:

http://rubyforge.org/projects/eventmachine

EventMachine not only makes network I/O easier to deal with,
it's also a high performance library. So you won't be sacrificing
speed for ease of use.

EventMachine also supports protocol helper modules that you can
use to mix-in higher level functionality than just sending and
receiving byte stream bursts.

For example, if you were writing a line-based protocol, like
POP3, SMTP, or FTP, you could start with:

  class MyProtocol < EventMachine::Protocols::LineAndTextProtocol

    def receive_line(line)
      # eventmachine LineAndTextProtcol will call your
      # receive_line method when a full line is received
      # for you to process
    end

    def send_line(line)
      line += "\n" unless line[-1] == ?\n # add EOL if not present
      send_data(line)
    end

  end

  EventMachine::start_server host, port, MyProtocol

Regards,

Bill