IO::Socket::Timeout - IO::Socket with read/write timeout
version 0.30
use IO::Socket::Timeout; # creates a standard IO::Socket::INET object, with a connection timeout my $socket = IO::Socket::INET->new( Timeout => 2 ); # enable read and write timeouts on the socket IO::Socket::Timeout->enable_timeouts_on($socket); # setup the timeouts $socket->read_timeout(0.5); $socket->write_timeout(0.5); # When using the socket: use Errno qw(ETIMEDOUT EWOULDBLOCK); print $socket "some request"; my $response = <$socket>; if (! $response && ( 0+$! == ETIMEDOUT || 0+$! == EWOULDBLOCK )) { die "timeout reading on the socket"; }
IO::Socket provides a way to set a timeout on the socket, but the timeout will be used only for connection, not for reading / writing operations.
IO::Socket
This module provides a way to set a timeout on read / write operations on an IO::Socket instance, or any IO::Socket::* modules, like IO::Socket::INET.
IO::Socket::*
IO::Socket::INET
IO::Socket::Timeout->enable_timeouts_on($socket);
Given a socket, it'll return it, but will enable read and write timeouts on it. You'll have to use read_timeout and write_timeout on it later on.
read_timeout
write_timeout
Returns the socket, so that you can chain this method with others.
If the argument is undef, the method simply returns empty list.
undef
These methods are to be called on a socket that has been previously passed to enable_timeouts_on().
enable_timeouts_on()
my $current_timeout = $socket->read_timeout(); $socket->read_timeout($new_timeout);
Get or set the read timeout value for a socket created with this module.
my $current_timeout = $socket->write_timeout(); $socket->write_timeout($new_timeout);
Get or set the write timeout value for a socket created with this module.
$socket->disable_timeout;
Disable the read and write timeouts for a socket created with this module.
$socket->enable_timeout;
Re-enable the read and write timeouts for a socket created with this module.
my $is_timeout_enabled = $socket->timeout_enabled(); $socket->timeout_enabled(0);
Get or Set the fact that a socket has timeouts enabled.
When a timeout (read, write) is hit on the socket, the function trying to be performed will return undef or empty string, and $! will be set to ETIMEOUT or EWOULDBLOCK. You should test for both.
$!
ETIMEOUT
EWOULDBLOCK
You can import ETIMEOUT and EWOULDBLOCK by using POSIX:
POSIX
use Errno qw(ETIMEDOUT EWOULDBLOCK);
If you want to implement a try / wait / retry mechanism, I recommend using a third-party module, like Action::Retry. Something like this:
Action::Retry
my $socket; my $action = Action::Retry->new( attempt_code => sub { # (re-)create the socket if needed if (! $socket) { $socket = IO::Socket->new(...); IO::Socket::Timeout->enable_timeouts_on($socket); $socket->read_timeout(0.5); } # send the request, read the answer $socket->print($_[0]); defined(my $answer = $socket->getline) or $socket = undef, die $!; $answer; }, on_failure_code => sub { die 'aborting, to many retries' }, ); my $reply = $action->run('GET mykey');
You can give a list of socket modules names when use-ing this module, so that internally, composed classes needed gets created and loaded at compile time.
use IO::Socket::Timeout qw(IO::Socket::INET);
This module implements timeouts using one of two strategies. If possible (if the operating system is linux, freebsd or mac), it uses setsockopt() to set read / write timeouts. Otherwise it uses select() before performing socket operations.
setsockopt()
select()
To force the use of select(), you can set PERL_IO_SOCKET_TIMEOUT_FORCE_SELECT to a true value at compile time (typically in a BEGIN block)
Action::Retry, IO::Select, PerlIO::via::Timeout, Time::Out
Thanks to Vincent Pitt, Christian Hansen and Toby Inkster for various help and useful remarks.
Damien "dams" Krotkine
This software is copyright (c) 2013 by Damien "dams" Krotkine.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
To install IO::Socket::Timeout, copy and paste the appropriate command in to your terminal.
cpanm
cpanm IO::Socket::Timeout
CPAN shell
perl -MCPAN -e shell install IO::Socket::Timeout
For more information on module installation, please visit the detailed CPAN module installation guide.