# GServer send/receive limit

**URL:** <https://www.ruby-forum.com/t/gserver-send-receive-limit/138897>\
**Category:** Ruby\
**Created:** [May 28, 2008, 7:21pm UTC](https://www.ruby-forum.com/t/gserver-send-receive-limit/138897 "2008-05-28T19:21:35Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [May 28, 2008, 7:21pm UTC](https://www.ruby-forum.com/t/gserver-send-receive-limit/138897/1 "2008-05-28T19:21:35Z")

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Team,

Is there a limit on the amount of data transmitted via GServer?  
I am playing some code snipped found on the web, which I changed to send  
the  
output of a command from the server to the client.  
However, I have not been able to receive more than a few bytes, less  
than  
100 bytes.  
So I was wondering if there were a limit for send/receive under GServer.  
I  
could not find such limits on the rdoc.

Thank you

Victor

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<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [May 28, 2008, 7:31pm UTC](https://www.ruby-forum.com/t/gserver-send-receive-limit/138897/2 "2008-05-28T19:31:39Z")

</div>

On 28 May 2008, at 18:13, Victor R. wrote:

> Is there a limit on the amount of data transmitted via GServer?  
> I am playing some code snipped found on the web, which I changed to  
> send the  
> output of a command from the server to the client.  
> However, I have not been able to receive more than a few bytes, less  
> than  
> 100 bytes.  
> So I was wondering if there were a limit for send/receive under  
> GServer. I  
> could not find such limits on the rdoc.

I’ve never noticed a limit when I’ve been experimenting. Care to post  
a code snippet showing what you’re actually doing?

Ellie

## Eleanor McHugh Games With Brains [http://slides.games-with-brains.net](http://slides.games-with-brains.net)

raise ArgumentError unless @reality.responds\_to? :reason

---

<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [May 28, 2008, 9:30pm UTC](https://www.ruby-forum.com/t/gserver-send-receive-limit/138897/3 "2008-05-28T21:30:15Z")

</div>

On Wed, May 28, 2008 at 1:31 PM, Eleanor McHugh \<  
removed\_email\_address@domain.invalid\> wrote:

> > 
> 
> * * *
> 
> raise ArgumentError unless @reality.responds\_to? :reason

Well, as I said earlier, I found these pieces of code in a website named  
[games-with-brains.com](http://games-with-brains.com), which I think you have something to do with it,  
and  
perhaps it has your picture.  
It looks like some nice pieces of code, which I’ve been trying to make  
it  
work for me so I can incorporate it’s functionality on my script. I am  
specifically interested in the way your code establish the connection  
and  
keeps it.  
Today I use TCP on a simple client/server (The client issues a request  
to a  
remote server, which is listening on a port. The server processes the  
request and sends the outcome back to the client).

However my new requirements include the need for the client/server to  
exchange some handshaking. Once the initial handshaking is done, the  
server  
will process the requested operation and returns any output to the  
client.  
The code I found on the web is able to establish and keep the connection  
for  
what I can see. The problem is that the client only receives 1 line of  
data.  
I played a bit displaying the data on the server side prior to sending  
it to  
the client and it looks good. But, pardon the repetition, the client  
only  
gets 1 line.  
The host file which I am using as my scape goat to send it across is  
actually about 300 lines.

Attached is the code I lifted from the website:

\*THE CLIENT  
cat gc22.rb  
#!/usr/local/ruby-1.8.6/bin/ruby -W0  
require ‘tcpc.rb’

class TimeClient \< TCPClient  
def send  
message = “#{Time.now}”  
puts “sending message: #{message}”  
super message  
end

```
    def on_response
            line = receive
            print "#{line}"
    end

```

end

client = TimeClient.new  
(1…2).each do |i|  
client.connect(“localhost”, 12341955)  
client.send  
client.on\_response  
puts “==========”  
client.disconnect  
sleep 3  
end

THE SERVER:  
cat gs2.rb  
#!/usr/local/ruby-1.8.6/bin/ruby -W0  
require ‘gserver’  
class TestServer \< GServer  
def serve( io )  
begin  
io.puts “\>\> WELCOME \<\<”  
loop do  
begin  
telnet\_input = io.gets  
puts “The input: #{telnet\_input}”  
break if telnet\_input =~ /\Aquit\b/  
cmd = `cat /etc/hosts`

```
                  io.puts cmd

                  if telnet_input.chomp.include? "shutdown"
                     self.stop
                  end
                  io.puts eval(telnet_input)
            rescue Exception
                  io.puts "Oops - " + $!
        end
            log "Rec'd " + telnet_input
       end
     io.puts ">> GOODBYE <<"
     io.close
    rescue Exception
        puts "OOPS - " + $!
        raise
      end
    end

```

end  
ts = TestServer.new 12341955  
ts.start  
ts.audit = true  
ts.join

THE GLUE THAT KEEPS EVERYTHING TOGETHER, I THINK. Although I don’t  
understand it well.  
cat tcpc.rb  
#!/usr/local/ruby-1.8.6/bin/ruby -W0  
require ‘socket’

EndPoint = Struct.new(:host, :port)

class TCPClient  
attr\_reader :remote, :status

```
    def connect remote_host, remote_port
            raise if @socket
            puts "starting client"
            @remote = EndPoint.new(remote_host, remote_port)
            @socket = TCPSocket.new(@remote.host, @remote.port)
    end

    def send message
            @socket.puts(message)
            on_response
    end

    def on_response; end

    def receive
            raise unless @socket
            begin
                    response = @socket.gets
            end until response
            response
    end

    def disconnect
            @socket.close
            @socket = nil
    end

```

end

# =============================== SAMPLE SESSION gs2.rb [Wed May 28 15:04:42 2008] TestServer 127.0.0.1:21187 client:38691 loopback\< 127.0.0.1\> connect The input: Wed May 28 15:04:42 -0400 2008 OOPS - Broken pipe [Wed May 28 15:04:42 2008] TestServer 127.0.0.1:21187 client:38691 disconnect [Wed May 28 15:04:45 2008] TestServer 127.0.0.1:21187 client:38692 loopback\< 127.0.0.1\> connect The input: Wed May 28 15:04:45 -0400 2008 [Wed May 28 15:04:45 2008] Rec’d Wed May 28 15:04:45 -0400 2008 The input: OOPS - Broken pipe [Wed May 28 15:04:45 2008] TestServer 127.0.0.1:21187 client:38692 disconnect

gc22.rb  
starting client  
sending message: Wed May 28 15:04:42 -0400 2008

> > WELCOME \<\<  
> > 127.0.0.1 loopback localhost # loopback (lo0) name/address  
> > ==========  
> > starting client  
> > sending message: Wed May 28 15:04:45 -0400 2008  
> > WELCOME \<\<  
> > 127.0.0.1 loopback localhost # loopback (lo0) name/address  
> > ==========

-

---

<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [May 29, 2008, 7:25am UTC](https://www.ruby-forum.com/t/gserver-send-receive-limit/138897/4 "2008-05-29T07:25:18Z")

</div>

On 28 May 2008, at 20:08, Victor R. wrote:

> Well, as I said earlier, I found these pieces of code in a website  
> named  
> [games-with-brains.com](http://games-with-brains.com), which I think you have something to do with  
> it, and  
> perhaps it has your picture.

That would be me, and my cruddy code as well so I guess I’d better  
give you some help 🙂

> Attached is the code I lifted from the website:
> 
> \*THE CLIENT
> 
> client = TimeClient.new  
> (1…2).each do |i|  
> client.connect(“localhost”, 12341955)  
> client.send  
> client.on\_response

The above line is a bug. My TCPClient class defines send so that it  
automatically calls on\_response, so calling on\_response a second time  
will cause the program to hang because the server is still waiting for  
a request to respond to. Oddly this isn’t apparent in the example  
provided, which goes to prove that just because code appears to work  
doesn’t mean it really does.

Thank goodness we put that disclaimer at the front 😉

> class TestServer \< GServer  
> io.puts cmd  
> io.puts “\>\> GOODBYE \<\<”  
> ts.join  
> You’ll want to do something to restrict the eval, otherwise you have a  
> potential security black hole, and you don’t need the io.close call as  
> that should be taken care of automatically when the serve method  
> returns.

> THE GLUE THAT KEEPS EVERYTHING TOGETHER, I THINK. Although I don’t  
> understand it well.

It’s basically just an OO wrapper to make writing a TCP client  
slightly less tedious. The example provided in the presentation is  
pretty lousy due to the time constraints of that medium (we always end  
up packing in too much content for a 45 minute session) and a more  
elegant implementation would mirror the block version of IO.open,  
removing the need to explicitly connect and disconnect.

> ```
> raise if @socket
> def on_response; end
> 
> ```

The two methods above define a callback mechanism so that an object  
can override on\_response and this will automatically be called when a  
message is sent. Most times this would probably be done by subclassing.

> ```
> def receive
> raise unless @socket
> begin
> response = @socket.gets
> end until response
> response
> end
> 
> ```

And the begin…end clause here is unnecessary thanks to gets being a  
blocking call, so:

def receive  
raise unless @socket  
@socket.gets  
end

> ```
> def disconnect
> @socket.close
> @socket = nil
> end
> 
> ```
> 
> end

Anyway, I’ll update the presentation to fix the bug and upload a new  
copy so that no one else wastes time over it.

Ellie

## Eleanor McHugh Games With Brains [http://slides.games-with-brains.net](http://slides.games-with-brains.net)

raise ArgumentError unless @reality.responds\_to? :reason

---

<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [May 29, 2008, 1:14pm UTC](https://www.ruby-forum.com/t/gserver-send-receive-limit/138897/5 "2008-05-29T13:14:05Z")

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On Thu, May 29, 2008 at 1:19 AM, Eleanor McHugh \<  
removed\_email\_address@domain.invalid\> wrote:

> > ```
> > client.disconnect
> > begin
> > if telnet_input.chomp.include? "shutdown"
> > rescue Exception
> > 
> > ```
> 
> to the time constraints of that medium (we always end up packing in too much
> 
> > class TCPClient  
> > @socket.puts(message)  
> > def receive
> 
> > 
> 
> ## [http://slides.games-with-brains.net](http://slides.games-with-brains.net)
> 
> raise ArgumentError unless @reality.responds\_to? :reason

Eleanor,

Thank you for taking the time to explain this to me. I truly appreciate  
it.  
I’ll play with the updated version and see how to use it on my own code.

Thanks a bunch!

Victor

---

<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [May 29, 2008, 2:02pm UTC](https://www.ruby-forum.com/t/gserver-send-receive-limit/138897/6 "2008-05-29T14:02:30Z")

</div>

On 29 May 2008, at 12:13, Victor R. wrote:

> Eleanor,
> 
> Thank you for taking the time to explain this to me. I truly  
> appreciate it.  
> I’ll play with the updated version and see how to use it on my own  
> code.
> 
> Thanks a bunch!

No problem. Thanks to your help there’s now one less bug in my  
presentation, and the revised copy should be available for download  
later today.  
If you have any further problems, let me know and I’ll see if I can  
help.

Ellie

## Eleanor McHugh Games With Brains [http://slides.games-with-brains.net](http://slides.games-with-brains.net)

raise ArgumentError unless @reality.responds\_to? :reason