I have some questions about the following code.

1. How reliable is it to use the -s file test operator so soon after calling $mech->get considering the file contents may still be in a RAM buffer? (Especially for a small file (e.g. this one is 2,575 bytes).)

2. So I thought, "Can I use the size from the response header?" I read the docs about Mech's get, and HTTP::Response, but I can't figure out how to do so.

3. Should I even consider using the content-length for an accurate (reliable) measure of the file size considering the affects from gzip'ping and etc.? I.e., is -s the "only" way to get an accurate/reliable file size?

#! /usr/bin/perl -w

use strict;
use Data::Dump qw(pp);
use WWW::Mechanize;

my $url  = 'http://perlmonks.org/images/vroom_sm.gif';
my $mech = WWW::Mechanize->new();
my $http_resp_obj = $mech->get( $url, ':content_file' => 'vroom_sm.gif
+' );
if ( $mech->success ) {
  # What if file buffer(s) haven't been flushed yet?
  print "File size is ", -s 'vroom_sm.gif', "\n";
  # I could not figure out how to get the value of the 'content-length
+' key
  # despite examining the output from:
  # pp($http_resp_obj);
  print "Content length is $http_resp_obj->header('content-length')\n"
+;
} else {
  warn "Failed to download '$url' (" . $mech->status() . ")\n";
}
[download]