JSON  With Perl

This chapter covers the way to encode and decode JSON objects using the Perl programming language. Let's start with preparing the environment to begin our programming with Perl for JSON.

Environment

Before you begin encoding and decoding JSON using Perl, you want to install a JSON module, which may be obtained from CPAN. Once you downloaded JSON-2.53.tar.gz or some other latest version, follow the steps noted below −

$tar xvfz JSON-2.53.tar.gz
$cd JSON-2.53
$perl Makefile.PL
$make
$make install

JSON Functions

Encoding JSON in Perl (encode_json)

The Perl encode_json() function transforms the available Perl data structure to a UTF-8 encoded, binary string.

Syntax

$json_text = encode_json ($perl_scalar );
or
$json_text = JSON->new->utf8->encode($perl_scalar);

Example

Arrays under JSON with Perl is shown in the below given example:

#!/usr/bin/perl
use JSON;
my %rec_hash = ('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);
my $json = encode_json \%rec_hash;
print "$json\n";

While applying, you will generate the result given below:
{"e":5,"c":3,"a":1,"b":2,"d":4}
How Perl objects can be transformed into JSON, in the below given example:
#!/usr/bin/perl
package Emp;
sub new {
   my $class = shift;
   my $self = {
      name => shift,
      hobbies  => shift,
      birthdate  => shift,
   };
   bless $self, $class;
   return $self;
}

sub TO_JSON { return { %{ shift() } }; }
package main;
use JSON;

my $JSON = JSON->new->utf8;
$JSON->convert_blessed(1);

$e = new Emp( "sachin", "sports", "8/5/1974 12:20:03 pm");
$json = $JSON->encode($e);
print "$json\n";

After applying, it will generate the below given result:

{"birthdate":"8/5/1974 12:20:03 pm","name":"sachin","hobbies":"sports"}

Decoding JSON in Perl (decode_json)

The Perl decode_json() function is made in use for decoding JSON in Perl. This function gives back the value decoded from JSON to an appropriate Perl type.

Syntax

$perl_scalar = decode_json $json_text
or
$perl_scalar = JSON->new->utf8->decode($json_text)

Example

The below given example represents how Perl can be made in use to decode JSON objects. Here you want to install the Data::Dumper module if you already do not have it on your device.

#!/usr/bin/perl
use JSON;
use Data::Dumper;

$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

$text = decode_json($json);
print  Dumper($text);

On applying, it will generate result given below:

$VAR1 = {
   'e' => 5,
   'c' => 3,
   'a' => 1,
   'b' => 2,
   'd' => 4
};