Using popen with 0,1,2,3,4 streams

Ruby
1

Hi !

I try to run command system and get streams handlers to 0 (stdin),
1(stdout), 2(stderr), 3(myOwnStdIn1), 4(myOwnStdIn2). I do something
like that in PHP by proc_open and table of pipes, but here I don’t
know how I can get handlers to process streams. I know that this code
is bad but I think something like this:

process = popen(‘command’, ‘w+’);
stdin = process.new(0, “w”);
stdout = process.new(1, “r”);

etc…

But new is a static method. What i should to do ?

2

Jan,

You might look at popen3 in the standard library. I don’t think it
quite
does what you need (since it returns an array if three pipes: stdin,
stdout
and stderr for the subprocess) but the code is short if a little arcane,
and
might point you in the right direction to figure this out.

Judson

3

On Dec 3, 2007 5:32 PM, Judson L. [email protected] wrote:

On Dec 2, 2007 3:10 AM, Jan Koprowski [email protected] wrote:

stdin = process.new(0, “w”);
stdout = process.new(1, “r”);

etc…

But new is a static method. What i should to do ?

Also take a look at open4 and systemu. You can find both at the
codeforpeople project on RubyForge. They, too, will offer some good
insight on what you want to do, though neither does precisely what you
need.

http://rubyforge.org/projects/codeforpeople

Blessings,
TwP

4

On 4 Gru, 17:58, Tim P. [email protected] wrote:

is bad but I think something like this:
codeforpeople project on RubyForge. They, too, will offer some good
insight on what you want to do, though neither does precisely what you
need.

http://rubyforge.org/projects/codeforpeople

Blessings,
TwP

Thank You for respond. I know that I can use only 3 pipes. But I think
I can look for open4 and try to write something similar. Thanks !

5

On 4 Gru, 17:58, Tim P. [email protected] wrote:

is bad but I think something like this:
codeforpeople project on RubyForge. They, too, will offer some good
insight on what you want to do, though neither does precisely what you
need.

http://rubyforge.org/projects/codeforpeople

Blessings,
TwP

U try to write something like this:

To change this template, choose Tools | Templates

and open the template in the editor.

require ‘fcntl’
require ‘timeout’
require ‘thread’

class Broker_process3

READ = 0 # Consts to explicite mark read
WRITE = 1 # and write pipes
@stdin
@stdout
@stderr

def initialize

end

def self.run (command, params)
pw, pr, pe, pl, pp = IO.pipe, IO.pipe, IO.pipe, IO.pipe, IO.pipe
pl.last.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
pp.last.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)

pid = fork {
  pw.last.close
  STDIN.reopen pw.first
  pw.first.close

  pr.first.close
  STDOUT.reopen pr.last
  pr.last.close

  pe.first.close
  STDERR.reopen pe.last
  pe.last.close

  pl.last.close
  pp.last.close

  STDOUT.sync = STDERR.sync = true

  exec(*command)
}

[pw.first, pr.last, pe.last, pl.first, pp.first].each{|fd|

fd.close}

pl.last.write("login"); // ERROR HERE
pl.last.close
pp.last.write("has³o");
pp.last.close

pw.last.close
out = pr.first.readlines
pr.first.close
pe.first.close
puts out;

end
end

but in // ERROR HERE I get:

./broker_process3.rb:48:in write': Broken pipe (Errno::EPIPE) from ./broker_process3.rb:48:in run’
from /home/johny/NetBeansProjects/zhradmin/lib/main.rb:12

6

On 4 Gru, 17:58, Tim P. [email protected] wrote:

is bad but I think something like this:
codeforpeople project on RubyForge. They, too, will offer some good
insight on what you want to do, though neither does precisely what you
need.

http://rubyforge.org/projects/codeforpeople

Blessings,
TwP

U try to write something like this:

To change this template, choose Tools | Templates

and open the template in the editor.

require ‘fcntl’
require ‘timeout’
require ‘thread’

class Broker_process3

READ = 0 # Consts to explicite mark read
WRITE = 1 # and write pipes
@stdin
@stdout
@stderr

def initialize

end

def self.run (command, params)
pw, pr, pe, pl, pp = IO.pipe, IO.pipe, IO.pipe, IO.pipe, IO.pipe
pl.last.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
pp.last.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)

pid = fork {
  pw.last.close
  STDIN.reopen pw.first
  pw.first.close

  pr.first.close
  STDOUT.reopen pr.last
  pr.last.close

  pe.first.close
  STDERR.reopen pe.last
  pe.last.close

  pl.last.close
  pp.last.close

  STDOUT.sync = STDERR.sync = true

  exec(*command)
}

[pw.first, pr.last, pe.last, pl.first, pp.first].each{|fd|

fd.close}

pl.last.write("login"); // ERROR HERE
pl.last.close
pp.last.write("has³o");
pp.last.close

pw.last.close
out = pr.first.readlines
pr.first.close
pe.first.close
puts out;

end
end

but in // ERROR HERE I get:

./broker_process3.rb:48:in write': Broken pipe (Errno::EPIPE) from ./broker_process3.rb:48:in run’
from /home/johny/NetBeansProjects/zhradmin/lib/main.rb:12