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Re: Calculating differences between the contents of a zip and a directory

by graff (Chancellor)
on Nov 03, 2012 at 05:44 UTC ( #1002076=note: print w/replies, xml ) Need Help??


in reply to Calculating differences between the contents of a zip and a directory

I think the right tool for this job would be Archive::Zip. Here's one way to do what you described - you want to be able to compare file sizes, and when they match, you want to compare the CRC32 values, just to be sure.

(And if you don't want to trust just the file-size and CRC comparisons, it would be easy enough, and some extra run-time, to test if file contents from the zip are equal to (eq) file contents from the directory. But that's probably overkill.)

#!/usr/bin/perl use strict; use Archive::Zip; my $Usage = "$0 file.zip [test_path]\n (default test_path is '.')\n"; die $Usage unless ( @ARGV and -f $ARGV[0] ); my $zipfile = shift; my $testpath = shift || '.'; my $zip = Archive::Zip->new( $zipfile ) or die "Archive::Zip was unable to read $zipfile\n"; my ( @missing_from_path, @altered ); for my $member ( $zip->members ) { next if ( $member->isDirectory ); my $filepath = $member->fileName; if ( ! -f "$testpath/$filepath" ) { push @missing_from_path, $filepath; next; } if ( -s _ == $member->uncompressedSize ) { if ( open( my $testfile, '<', "$testpath/$filepath" )) { local $/; $_ = <$testfile>; close $testfile; my $testCRC = $zip->computeCRC32( $_ ); next if ( $testCRC eq $member->crc32 ); } else { warn "Unable to read $testpath/$filepath: $!\n"; } } push @altered, $filepath; } print "Comparing $zipfile to $testpath:\n"; if ( @missing_from_path ) { print " Missing files:\n"; print " $testpath/$_\n" for ( sort @missing_from_path ); } else { print " No files missing\n"; } if ( @altered ) { print " Altered files:\n"; print " $testpath/$_\n" for ( sort @altered ); } else { print " No altered files\n"; } =head1 NAME zip-check -- check zip file against directory contents =head1 SYNOPSIS zip-check [path/to/]file.zip [test_path] (default test_path is '.') =head1 DESCRIPTION This script will compare the contents of a given zip file against the contents of a given directory (current working directory by default). We check for two types of differences: - Files in the zip archive that are not found in the directory - Files found in both places, but having different contents (based on comparing their CRC32 values) (We do not report cases where the directory contains files that are not found in the zip archive.) =head1 AUTHOR David Graff <graff at ldc dot upenn dot edu> =cut

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Re^2: Calculating differences between the contents of a zip and a directory
by MilanorTSW (Beadle) on Nov 03, 2012 at 11:05 UTC

    Ah, many thanks.

    Now, I did think it could be possible to just compare sizes, but it wasn't completely trusted.

    I didn't think of CRC comparisons.

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