# TCPSocket Connection

**URL:** <https://www.ruby-forum.com/t/tcpsocket-connection/76079>\
**Category:** Ruby\
**Created:** [December 26, 2005, 3:59am UTC](https://www.ruby-forum.com/t/tcpsocket-connection/76079 "2005-12-26T03:59:11Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\
**Post date:** [December 26, 2005, 3:59am UTC](https://www.ruby-forum.com/t/tcpsocket-connection/76079/1 "2005-12-26T03:59:11Z")

</div>

I am working on a network application on an unstable network. I need to  
do something like call client.connected?() on the server side to see if  
the clients are still connected before I try to write to them. Any  
ideas?

---

<div class="post-metadata">

**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\
**Post date:** [December 26, 2005, 9:23am UTC](https://www.ruby-forum.com/t/tcpsocket-connection/76079/2 "2005-12-26T09:23:39Z")

</div>

“removed\_email\_address@domain.invalid” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

> I am working on a network application on an unstable network. I need to  
> do something like call client.connected?() on the server side to see if  
> the clients are still connected before I try to write to them. Any  
> ideas?

If the network is unstable, that means there could be instances where  
a connection is disconnected improperly. This means, either end may  
not know that the other has gone away.

There is no heart beat in TCP protocol (there actually is: the keep  
alive packet, but 1. you can’t rely on that being enabled by the other  
side, 2. the default interval is 2 hours, way too long for most  
apps), so you can’t readily be informed of any disruption.

The only way to see if the other side has gone away is to try to  
perform IO on the connection.

In the case of writing, you’ll get an exception if the other side has  
gone away.

In the case of reading, if the connection was closed amicably, you’ll  
get an end-of-stream (0-byte read), otherwise, it may just block  
indefinitely.

Therefore, it is of utmost importance to always set some timeout when  
trying to read because you can never know if the connection has became  
invalid. In ruby, you can simply use the timeout library (require  
‘timeout’).

YS.

---

<div class="post-metadata">

**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\
**Post date:** [December 26, 2005, 3:24pm UTC](https://www.ruby-forum.com/t/tcpsocket-connection/76079/3 "2005-12-26T15:24:54Z")

</div>

I should have mentioned that this is only a one way write from the  
server. So, what I am currently doing is trying to write to the client  
and catching the exception if it is no longer connected. It just seems  
a little kludgy to do that. And I wanted to get a feel for what other  
people have done in this situation. Thanks.