Decode with base64 a text file gzipped and read it - perl

Question

I retrieve from a system a text file which has as been (in order):
gzipped
encoded with base64
So I would like in Perl to decode it, unzip it and read it without passing by intermediate file.
I tried the following:
use Compress::Zlib;
use MIME::Base64;
my $workingDir = "./log/";
my $inputFile = $workingDir . "log_result_base64.txt";
my $readtmp ='';
open (INPFIC, $inputFile) or die "ERROR: Impossible to open file ($inputFile)\n";
while (my $buf = <INPFIC> ) {
$readtmp .= decode_base64($buf);
}
close(INPFIC);
my $output = uncompress($readtmp);
print $output;
But it does not work, the $output variable is still undef.
[Edit]
I gave up to do it by passing only by Variable.
I changed my script by creating a new file at each stage:
#!/usr/bin/perl
use strict ;
use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
use MIME::Base64;
my $inputFile = $workingDir . "log_inbase64.txt";
my $inputFilegz = $workingDir . "log.txt.gz";
my $inputFileuncomp = $workingDir . "log.txt";
my #out;
my #readtmp;
my $readtmp;
# Reading the file encoded in base64
open (INPFIC, $inputFile) or die "ERROR: Impossible to open file ($inputFile)\n";
my #readtmp = <INPFIC>;
close(INPFIC);
$readtmp = join('',#readtmp);
# Decode in base64 to retreive a Gzip file
my $out = decode_base64($readtmp);
open my $fh, '>', $inputFilegz or die $!;
binmode $fh;
print $fh $out;
close $fh;
# Decompress the early created gzip file
gunzip $inputFilegz => $inputFileuncomp
or die "gunzip failed: $GunzipError\n";
# Reading the Text file
open (INPFIC, $inputFileuncomp) or die "ERROR: Impossible to open file ($inputFileuncomp )\n";
my #out = <INPFIC>;
close(INPFIC);

Answer 1

The uncompress method does not work for gzipped data.
IO::Uncompress::Gunzip can use scalar references instead of file names if you want to keep everything in memory.
Sample code:
use IO::Uncompress::Gunzip qw( gunzip $GunzipError );
use MIME::Base64 qw( decode_base64 );
my $tmp = decode_base64 do {
local $/;
<DATA>
};
gunzip \$tmp => \my $data or die "Could not gunzip: $GunzipError";
print $data;
__DATA__
H4sIAHWHLlUAAwvJyCxWAKLi/NxUhZLU4hKFlMSSRC4AsSDaaxcAAAA=
Should produce:
This is some test data

Answer 2

I'd put the whole file in a string before decode:
local $/ = undef;
my $str = <INPFIC>
my $dec = decode_base64 $str;
my $uncom = uncompress($dec)

Answer 3

According to Compress::Zlib doc, try to open and read in same time:
my $workingDir = "./log/";
my $inputFile = $workingDir . "log_result_base64.txt";
my $buffer;
my $output;
my $gz = gzopen($inputFile,"rb")
or die "Cannot open $inputFile: $gzerrno\n" ;
while ( $gz->gzread($buffer) > 0 ){
$output .= decode_base64 $buffer;
}
die "Error reading from $inputFile: $gzerrno" . ($gzerrno+0) . "\n"
if $gzerrno != Z_STREAM_END ;
$gz->gzclose();
print $output;