Gentlemonks,

My lab has a fair number of conference papers and proceedings stashed away as PDFs. I'm trying to write a program to index them and create a web-page interface (which I hope will be more friendly than a ten-level directory tree). The papers' filenames almost invariably contain no more useful information than the primary author's last name, so I'm trying to use PDF::Parse to extract title and author information.

Unfortunately, my script fails with 

PDF::Core::PDFGetPrimitive() called too early to check prototype at PD
+F/Core.pm line 288.
PDF::Core::PDFGetPrimitive() called too early to check prototype at PD
+F/Core.pm line 294.
Argument "" isn't numeric in seek at PDF/Core.pm line 556.
Can't read cross-reference section, according to trailer

[download]
and I can't glean enough context from the module's documentation to know when PDF::Core::PDFGetPrimitive() should be called, or why a trailer might not be able to read a cross-reference section.

In fact, I'm finding it very difficult to debug based on the docs for PDF::Parse -- they seem to describe what the module's various functions will do if they succeed, but not what's necessary to ensure success.

My code, mildly edited for length, follows: 

#! /usr/bin/perl -w

use strict;
use File::Find;
use Data::Dumper;
use PDF;
use PDF::Parse;

my %conferences     = ();
my $start_dir       = "/gruvi/Data/Proceedings";

sub find_pdfs
{
    # simple, yet shoud be effective
    if(/\.pdf$/) {
        # NOTE: this seems to ignore "top-level" PDFs
        #  That's not a bug, it's a feature!
        my ($conference) = ($File::Find::dir =~ m!$start_dir/(\w+?)/!)
+;
        $conference ||= "Top-level";
        push @{$conferences{$conference}}, "$File::Find::dir/$_";
        return 1;
    }

    return 0;
}

&File::Find::find(\&find_pdfs, $start_dir);

for (sort keys %conferences) {
    &write_conference_page($_, "$_.html", $conferences{$_});
}

sub write_conference_page
{
    my ($conference, $outfile, $pdfs) = @_;

    open PROCS, '>', "./$outfile"
        or die "Cannot open $outfile: $!\n";

    # we're going to callously ignore proper HTML for the present
    print PROCS "<html>\n<body>\n";

    # we're also going to callously ignore proper Perl HTML-gen style
    #  for the moment
    print PROCS "<h3>$conference</h3>\n";
    print PROCS "<ul>\n";
    for (@$pdfs) {
        my $pdf     = PDF->new($_);
        $pdf->TargetFile($_);
        my $title   = $pdf->GetInfo("Title");
        my $authors = $pdf->GetInfo("Author");
        print PROCS "\t<li>$authors:<br>";
        print PROCS "<a href=\"file://$_\">$title</a></li>\n";
    }
    print PROCS "</ul>\n<hr>\n\n";

    print PROCS "</body>\n</html>\n";

    close PROCS
        or die "Cannot close $outfile: $!\n";
}

[download]
I'll freely admit that the code around $pdf is cargo-cult stuff -- I couldn't tell from the docs what I was expected to do to make a PDF object, so I just copied from the synopses.

This code fails to generate any of the conference index pages. Any ideas?

--
F o x t r o t U n i f o r m
Found a typo in this node? /msg me
% man 3 strfry

In reply to PDF::Parse fails with obscure error messages by FoxtrotUniform

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