How to check if a zip fie is empty using perl - perl

Question

I'm writing a Perl scipt that unzips the zip file and moves the content of zip file to a directory, however I want to skip the zip file which do not have any content in it. How can I filter these files. For unzipping the file I'm using
unzip_content = system("unzip -d <directory> -j -a <filepath>")
Could anyone suggest me anyway to check if it does not contain anything.
I tried with checking the filesize using -s $filename but later I got some files with filesize 22 byte but with no content in it.

Answer 1

You can use Archive::Zip to achieve all of that inside of your Perl program without shelling out. You need to check if the archive contains anything, which can be done with the numberOfMembers method.
use strict;
use warnings;
use Archive::Zip qw/:ERROR_CODES/;
my #files = ...;
foreach my $file (#files) {
my $zip = Archive::Zip->new;
# skip if archive cannot be opened
next unless $zip->read($file) == AZ_OK;
# skip if archive is empty
next unless $zip->numberOfMembers;
# extract everything
$zip->extractTree({zipName => '<directory>'});
}

Answer 2

An other way to check the same thing is to calculate the MD5 hash of the file. MD5 hash of all empty zip files would be 76cdb2bad9582d23c1f6f4d868218d6c.
Helpful links:
minimum size zip file
Digest::MD5
use strict;
use warnings;
use Digest::MD5 qw(md5 md5_hex md5_base64);
my $filedir = "/home/docs/file.zip";
open FILE, "$filedir";
my $ctx = Digest::MD5->new;
$ctx->addfile (*FILE);
my $hash = $ctx->hexdigest;
close (FILE);
if($hash eq '76cdb2bad9582d23c1f6f4d868218d6c')
{
# empty file
}