Perl decoding, for looping, & downloading - perl

Question

I wrote this script but I'm not sure if it is correct.
What I want to do is process a JSON file by reading its content, decoding it, and looping through each item as $item. The contents from a certain URL with the ID defined as $items[$i]['paper_item_id'] are saved with that ID into the defined destination.
But the code doesn't seem to function. I'm not sure on where I went wrong but any help or tips to improve the code and make it work would be good.
I'm not asking you to do the job, just need help seeing on where I went wrong and correct it for me.
The script should basically decode the JSON and then download the swf files from a certain directory URL to a directory on my PC using the IDs.
This is the code
use LWP::Simple;
$items = 'paper_items.json';
my $s = $items or die;
$dcode = decode_json($items);
for ($i = 0 ; $i < $count ($items) ; $i++) {
use File::Copy;
$destination = "paper/";
copy(
"http://media1.clubpenguin.com/play/v2/content/global/clothing/paper/"
. $items[$i]['paper_item_id'] . ".swf",
$destination . $items[$i]['paper_item_id'] . ".swf"
);

Answer 1

The program can be broken down into three steps:
Fetch the JSON source.
Parse the JSON.
Iterate over decoded data structure. We expect an array of hashes. Mirror files denoted by the paper_item_id to the working directory.
We will use LWP::Simple functions here.
Our script has the following header:
#!/usr/bin/perl
use strict; # disallow bad constructs
use warnings; # warn about possible bugs
use LWP::Simple;
use JSON;
Fetching the JSON
my $json_source = get "http://media1.clubpenguin.com/play/en/web_service/game_configs/paper_items.json";
die "Can't access the JSON source" unless defined $json_source;
That was easy: we dispatch a get request on that URL. If the output is undefined, we throw a fatal exception.
Parsing the JSON
my $json = decode_json $json_source;
That was easy; we expect the $json_source to be an UTF-8 encoded binary string.
If we want to inspect what is inside that data structure, we can print it out like
use Data::Dumper; print Dumper $json;
or
use Data::Dump; dd $json;
If everything works as expected, this should give a screenfull of an array of hashes.
Iterating
The $json is an array reference, so we'll loop over all items:
my $local_path = "paper";
my $server_path = "http://media1.clubpenguin.com/play/v2/content/global/clothing/paper";
for my $item (#$json) {
my $filename = "$item->{paper_item_id}.swf";
my $response = mirror "$server_path/$filename" => "$local_path/$filename";
warn "mirror failed for $filename with $response" unless $response == 200;
}
Perl has a concept of references, which is similar to pointers. Because data structures like hashes or arrays can only contain scalars, other arrays or hashes are only referenced. Given an array reference, we can access the array like #$reference or #{ $reference }.
To access an entry, the subscript operator [...] for arrays or {...} for hashes is seperated by the dereference operator ->.
Thus, given %hash and $hashref to the same hash,
my %hash = (key => "a", otherkey => "b");
my $hashref = \%hash;
then $hashref->{key} eq $hash{key} holds.
Therefore, we loop over the items in #$json. All of these items are hash references, therefore we use $item->{$key}, not $hash{key} syntax.

Answer 2

What you are trying to do is to download the Shockwave Flash resources from Disney's Club Penguin game site.
I cannot imagine Disney would be too happy about this, and the site's terms of use say this under "Use of Content" ("DIMG" is Disney Interactive Media Group)
Except as we specifically agree in writing, no Content from any DIMG Site may be used, reproduced, transmitted, distributed or otherwise exploited in any way other than as part of the DIMG Site ...

Answer 3

Code is untested.
use File::Slurp qw(read_file);
use JSON qw(decode_json);
use LWP::Simple qw(mirror);
for my $item (#{ decode_json read_file 'paper_items.json' }) {
my $id = $item->{paper_item_id};
mirror "http://media1.clubpenguin.com/play/v2/content/global/clothing/paper/$id.swf", "paper/$id.swf";
}