Call Python script and pass arguments from Perl script

[Ombongi.Moraa]

I use this command to call the python script and pass arguments;

$output="sudo /usr/bin/python /home/processLog.py '$name' '$age' '$text' '$id' ";

return `$output`

However, as it is, bad problems arise when the $text variable contains single or double quotes. How can I pass the variables wholly esp with quotes within them?

Thanks in advance.

[LanX]

try quotemeta

  DB<109> $text=q{a'b"c}; print quotemeta($text)
a\'b\"c
  DB<110> $name="Daffy Duck";
 => "Daffy Duck"

  DB<111> print "'\Q$name\E' '\Q$text\E'"
'Daffy\ Duck' 'a\'b\"c'

not sure if you really still need the single-quotes.

edit

expanded example

[aitap]

Try this:

my $output=qq{sudo /usr/bin/python /home/processLog.py \Q$name\E \Q$ag
+e\E \Q$text\E \Q$id\E};
return `$output`;

It works using interpolating quote-like operator qq{} and escaping operators \Q...\E, both described in Quote and Quote like Operators.

Another approach might be using open or modules like IPC::Run or IPC::Cmd to run a command with a list (not a string) of arguments:

open my $fh, "-|", qw{sudo /usr/bin/python /home/processLog.py}, $name
+, $age, $text, $id or die $!;
return do {local $/; <$fh>};

use IPC::Run;
run [qw{sudo /usr/bin/python /home/processLog.py}, $name, $age, $text,
+ $id], ">", \(my $return) or die "run: $?";
return $return;

Warning: all code in this message is untested.

Update: using quotemeta for quoting shell commands is a hack, you should run a list of arguments instead, or use at least some shell-related module like String::ShellQuote.

Update 2: the code I suggested will discard any newlines in the interpolated variables instead of escaping them properly, so I stroke it out. Thanks ambrus for correcting me.

_{Edit: removed quotes from \Q...\E approach as they are entirely unnecessary in this case.}

[ambrus]

I don't recommend using the quotemeta operator. That will usually misquote newlines with POSIX-like shells.

Instead, skip the shell and use the multiple argument form pipe open, such as

my $output; 
{ 
    my @command = "sudo", "/usr/bin/python", "/home/processLog.py", $n
+ame, $age, $text, $id;
    open my $P, "-|", @command or 
        die "error pipe opening program"; 
    local $/; 
    $output = <$P>; 
    close $P or 
        die "error: spawned program exited with failure or cannot read
+ pipe"; 
    # note: you may want to accept an exit failure with some programs.
+ if you do, check eof($P) instead to catch a read error.
} 
print $output;

Update: added "skip the shell".