mod_perl headers_in not working

Question

I'm using mod_perl 2 with Apache 2.2.3 on Red Hat 5.2, and I'm trying to access the request headers, but the Apache2::RequestRec headers_in method (or rather, its return value) is not behaving the way I would expect.

Code fragment:

$logger->warn('version ' . $mod_perl::VERSION);
$logger->warn('r ' . $r);
my $headers = $r->headers_in;
$logger->warn('headers ' . $headers);
my $accept = $headers->get('Accept');
$logger->warn('got $accept');
$logger->warn($accept);

gives the following log output:

WARN version 2.000004
WARN r Apache2::RequestRec=SCALAR(0x2ae0598e9ef0)
WARN headers APR::Table=HASH(0x2ae06cad15a0)

with execution appearing to halt as soon as any access to the APR::Table is attempted. The tied interface for APR::Table had the same effect - i.e. changing the get('Accept') line to:

my $accept = $headers->{Accept};

gives exactly the same log output.

According to the above linked documentation:

This table is available starting from the PerlHeaderParserHandler phase

So I would expect my code, running in the PerlResponseHandler phase, to be able to access the headers.

Does anyone have any ideas what I'm doing wrong?

Edit: Using Data::Dumper hasn't really clarified matters at all.

Code:

use Data::Dumper;
$logger->warn(Dumper($r));
my $headers = $r->headers_in;
$logger->warn($headers);
$logger->warn(Dumper($headers));
$logger->warn('have dumped $headers');

Output:

WARN $VAR1 = bless( do{\(my $o = '47143456365192')}, 'Apache2::RequestRec' );

WARN APR::Table=HASH(0x2ae071b06fd0)

So it seems that trying to get into $headers even through Data::Dumper results in the execution halting.

Edit: Attempting to set one of the headers fails as well.

$logger->warn('reset accept');
$r->headers_in->{'Accept'}= 'everything';
$logger->warn('post set accept');

stops log output at the

WARN reset accept

point. I tried the set(Accept => 'everything') alternative as well, with the same result.

Answer 1

Problem found:

I needed to add

use APR::Table;

somewhere. Kind of weird that it was happily able to create an APR::Table object though.

Answer 2

Is there anything in the apache logs? It seems if your code stops executing there should be an error somewhere saying why.

Answer 3

Have you tried getting the Accept header without assigning the header object to $header:

my $accept = $r->headers_in->get('Accept');

This works in my code running in the PerlResponseHandler phase.