[web] Perl sending messages to script....?
I made a script, which works oke. But now I want to expand it so it can receive certain commands in runtime. I want this for monitoring perposes, for example, I need to know what's in a certain variable.
I could write the values to a file but I don't want that because I would have to print it within an interval which doesn't let me see the live values.... a very small interval is not a smart idea either.
I hope you understand what I'm trying to tell.
Example: testscript.pl
The script is running for a few hours and I want to be able to send a command like "list actions".
You can listen on a socket:
then just connect with netcat or whatever, and pass it perl expressions:
e.g:
grazer@localhost grazer $ nc localhost 27690
$time
recieved: $time
Wed Jan 19 01:34:55 2005
grazer@localhost grazer $ nc localhost 27690
$name
recieved: $name
Bob
grazer@localhost grazer $ nc localhost 27690
1+1
recieved: 1+1
2
Just be careful that this is not exposed to the internet for obvious security reasons.
HTH,
-g
#!/usr/bin/perluse strict;use IO::Socket;$|++; # turn off buffering# set up a socketmy $sock = IO::Socket::INET->new( LocalPort => '27690', Type => SOCK_STREAM, Listen => 1, Reuse => 1, Timeout => .1, ) || die $!;# this is your script while (1){ # do whatever c00l stuff # you are already doing my $name = 'Bob'; my $time = localtime; # check for a command if (my $inc = $sock->accept) { while (defined(my $cmd = <$inc>)){ print $inc "recieved: $cmd"; print $inc eval $cmd, "\n"; $inc->close; } }}then just connect with netcat or whatever, and pass it perl expressions:
e.g:
grazer@localhost grazer $ nc localhost 27690
$time
recieved: $time
Wed Jan 19 01:34:55 2005
grazer@localhost grazer $ nc localhost 27690
$name
recieved: $name
Bob
grazer@localhost grazer $ nc localhost 27690
1+1
recieved: 1+1
2
Just be careful that this is not exposed to the internet for obvious security reasons.
HTH,
-g
Thanks [smile] I bet that will do the trick. Is there also a more secure way of achieving this? Anyway, it's meant to see the results of a few actions. I will put something in the code that it accepts only a couple of commands. Plus, I won't be using "eval" since I don't want to execute the commands I'm sending.
It will probably be something like this:
It will probably be something like this:
# check for a command if (my $inc = $sock->accept) { while (defined(my $cmd = <$inc>)) { if ($cmd eq 'dosomething') { print "I gotta do something\n"; } $inc->close; } }
The insecurity comes mostly from the "eval", in the actual system, I would most likely just set up a dispatch table of available commands, something like (untested):
this way, you can run specific callbacks without having to worry about executing arbitrary code.
good luck,
my %cmds = ( show_data => \&show_foo_data, my_foobar => \&foobar_method, finish => sub { exit },);$cmds{$command_from_network}->();sub show_foo_data { # do stuff}sub foobar_method { # do other stuff}this way, you can run specific callbacks without having to worry about executing arbitrary code.
good luck,
Hey that's a great idea (the hash thing). why didn't I come up with that idea? That's much better than using if statements... plus, it's easier to expand or disable commands.
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