JSON how can I check if keys and array exists? - json

Question

I have a JSON file, and I want to check if keys exists or not, if keys are empty or not.
I've already done this kind of check in the script below.
But, here I have "children" which is an empty array.
How can I see if this array exists or not and if this array is empty or not?
Here the JSON sample:
{
"id": "Store::STUDIO",
"name": "Studio",
"categories": [
{
"id": "Category::556",
"name": "Cinéma",
"children": []
},
{
"id": "Category::557",
"name": "Séries",
"children": []
}
],
"images": [
{
"format": "iso",
"url": "http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/installer-amd64/current/images/netboot/mini.iso",
"withTitle": false
}
],
"type": "PLAY"
}
Here is the script:
#!/usr/bin/perl
use strict;
use warnings;
use utf8;
use JSON qw( decode_json );
use JSON qw( from_json );
# JSON file
my $json_f = '/home/test';
# Variable
my $curl_cmd = "curl -o /dev/null --silent -Iw '%{http_code}'";
# JSON text
my $json_text = do {
open (TOP, "<", $json_f);
local $/;
<TOP>
};
my $decoded = from_json($json_text);
# Display value provider if exist
my $provider = $decoded->{"categories"}[0]{"provider"};
print $provider, "\n" if scalar $provider;
# Display value children if exist
my #child = $decoded->{"categories"}[0]{"children"};
print $child[0], "\n" if scalar #child;
# Checking an url is exist
my $url_src = $decoded->{"images"}[0]{"url"};
my $http_res = qx{$curl_cmd $url_src}; # Checking if URL is correct
# Display categories with others values
my #categories = #{ $decoded->{'categories'} };
foreach my $f ( #categories ) {
print $decoded->{"id"} . "|" . $f->{"id"} . "|" . $f->{"name"} . "|" . $http_res . "\n";
}

Answer 1

In your code, #child is an array of arrays. Dereference the array. Change:
my #child = $decoded->{"categories"}[0]{"children"};
to:
my #child = #{ $decoded->{"categories"}[0]{"children"} };