Christopher Grau wrote:
Hi,
I have a fairly simple problem, but haven't had much luck finding the
solution on Google or the mailing list archives. Basically, I have this
code in httpd.conf:
Perl
print Enter some value you don't want written down: ;
my $value = STDIN;
chomp $value;
print value = '$value'\n;
# The code works if I do this...
# $value = Foobar;
push @PerlSetVar, [Foo = $value];
/Perl
The value in $value prints to stdout, but the variable Foo doesn't get
set to $value. However, if I were to set $value to something
explicitly, as in the comment above, the code works fine.
Based on that, I'm guessing the problem lies with reading from STDIN.
What am I missing here?
This one was tricky. The reason for this misterious behavior lies in
fact that Apache restarts itself on start. The STDIN input is prompted
once and then on the restart $value gets overwritten with undef. If you
check your error_log you will see several warnings and errors regarding
this code. among which:
[Sun Nov 24 19:45:40 2002] [error] (25)Inappropriate ioctl for device:
Perl: PerlSetVar takes two arguments, Perl config var and value
First of all, it's easier to debug with:
Perl
use Apache::PerlSections();
$Apache::Server::SaveConfig = 1;
# set @Perl* here
print STDERR Apache::PerlSections-dump();
/Perl
notice the dump(). Remember that on start STDERR goes to the console. On
the restart it goes to error_log, therefore you want to watch both, as
it will be called twice.
using the dump() you will see that on restart no value is passed.
Here are two possible solution that work:
print Enter some value you don't want written down: ;
$mytmp::value ||= STDIN;
chomp $mytmp::value;
print value = '$mytmp::value'\n;
push @PerlSetVar, [Foo = $mytmp::value];
here, we use a global variable, so it survives the scope re-entrance. If
STDIN may return 0, you want to do:
$mytmp::value = STDIN unless defined $mytmp::value;
instead
Another longer but more self-documenting solution is as follows:
if ($Apache::Server::Starting) {
print Enter some value you don't want written down: ;
$mytmp::value = STDIN;
chomp $mytmp::value;
} else {
print value = '$mytmp::value'\n;
push @PerlSetVar, [Foo = $mytmp::value];
}
See also:
http://perl.apache.org/docs/1.0/guide/config.html#Apache_Restarts_Twice_On_Start
p.s. for now let's keep this trickery in the archives, if the question
is repeated, will add the answer to the docs.
__
Stas BekmanJAm_pH -- Just Another mod_perl Hacker
http://stason.org/ mod_perl Guide --- http://perl.apache.org
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