Google Vision API Annotate (OCR) from Perl

vision_ocr.pl

use strict;
use warnings;

use JSON;
use MIME::Base64;
use REST::Client;

use constant API_KEY => "KEY TEXT";
use constant URL => "https://vision.googleapis.com/v1/images:annotate?key=";

my $request_url = URL.API_KEY;
my $client = new REST::Client();
my $json = new JSON();

my $png;
{    local $/ = undef;
     open(PNG, $ARGV[0]) or die "Could not open the file: $!";
     binmode PNG;
     $png = <PNG>;
     close(PNG);
     $png = encode_base64($png);    
}

my %request;
$request{requests} = [
    {image => {content => $png},
    features => [{type =>  "DOCUMENT_TEXT_DETECTION"}]}
];

my $json_text = $json->encode(\%request);

$client->POST($request_url, $json_text);

##
# resonse code is in $client->responseCode();
# respose content is in $client->responseContent();
##