IO::WrapOutput - Wrap your output filehandles with minimal fuss
use IO::WrapOutput; use Module::Which::Hogs::STDOUT::And::STDERR; my $foo = Module::Which::Hogs::STDOUT::And::STDERR->new(); my ($stdout, $stderr) = wrap_output(); # read from $stdout and $stderr # then, later, restore the original handles $foo->shutdown; unwrap_output(); # example using POE::Wheel::ReadLine use strict; use warnings; use IO::WrapOutput; use POE; use POE::Wheel::ReadLine; use POE::Wheel::ReadWrite; POE::Session->create( package_states => [main => [qw(_start got_output got_input)]], ); $poe_kernel->run(); sub _start { my ($heap) = $_[HEAP]; $heap->{console} = POE::Wheel::ReadLine->new( InputEvent => 'got_input', ); my ($stdout, $stderr) = wrap_output(); $heap->{stdout_reader} = POE::Wheel::ReadWrite->new( Handle => $stdout, InputEvent => 'got_output', ); $heap->{stderr_reader} = POE::Wheel::ReadWrite->new( Handle => $stderr, InputEvent => 'got_output', ); # request the first line $heap->{console}->get('>'); } sub got_output { my ($heap, $line) = @_[HEAP, ARG0]; $heap->{console}->put($line); } sub got_input { my ($heap, $line, $exception) = @_[HEAP, ARG0, ARG1]; if (defined $exception && $exception eq 'interrupt') { # terminate the console unwrap_output(); delete $heap->{console}; delete $heap->{stdout_reader}; delete $heap->{stderr_reader}; print "Terminated\n"; return; } # do something with $line ... # request the next line $heap->{console}->get(); }
When you have a module (e.g. POE::Wheel::ReadLine) which needs all output to go through a method that it provides, it can be cumbersome (or even impossible) to change all the code in an asynchronous/event-driven program to do that instead of printing directly to STDOUT/STDERR. That's where IO::WrapOutput comes in.
IO::WrapOutput
You just do the setup work for the output-hogging module in question, then call wrap_output which will return filehandles that you can read from. Then you take what you get from those filehandles and feed it into your output-hogging module's output method. After you stop using the output-hogging module, you can restore your original STDOUT/STDERR handles with unwrap_output.
wrap_output
unwrap_output
Takes no arguments. Replaces the current STDOUT and STDERR handles with pipes, and returns the read ends of those pipes back to you. Any copies made of the STDOUT/STDERR handles before calling this function will still be attached to the process' terminal.
my ($stdout, $stderr) = wrap_output();
Takes no arguments. Restores the original STDOUT and STDERR handles.
Hinrik Örn Sigurðsson, hinrik.sig@gmail.com
Copyright 2011 Hinrik Örn Sigurðsson
This program is free software, you can redistribute it and/or modify it under the same terms as Perl itself.
To install IO::WrapOutput, copy and paste the appropriate command in to your terminal.
cpanm
cpanm IO::WrapOutput
CPAN shell
perl -MCPAN -e shell install IO::WrapOutput
For more information on module installation, please visit the detailed CPAN module installation guide.