Question

I’m working on a script which receives JSON code for an array of objects similar to this:

{
  "array":[
    { "id": 1, "text": "Some text" },
    { "id": 2, "text": "Some text" }
  ]
}

I decode it using JSON::XS and then filter out some of the results. After this, I need to store the JSON code for each individual node into a queue for later processing. The format this queue requires is JSON too, so the code I’d need to insert for each node would be something like this:

{ "id": 1, "text": "Some text" }

However, after decode_json has decoded a node, all that’s left are hash references for each node:

print $json->{'array'}[0]; # Would print something like HASH(0x7ffa80c83270)

I know I could get something similar to the original JSON code using encode_json on the hash reference, but the resulting code is different from the original code, UTF-8 characters get all weird, and it seems like a lot of extra processing, specially considering the amount of data this script has to deal with.

Is there a way to retrieve the original JSON code from a decoded array node? Does JSON::XS keep the original chunks somewhere after they have been decoded?

---

EDIT

About the weird UTF-8 characters, they just look weird on the screen:

#!/usr/bin/perl

use utf8;
use JSON::XS;
binmode STDOUT, ":utf8";

$old_json = '{ "text": "Drag\u00f3n" }';
$json = decode_json($old_json);
print $json->{'text'}; # Dragón

$new_json = encode_json($json);
print $new_json; # {"text":"Dragón"}

$json = decode_json($new_json);
print $json->{'text'}; # Dragón

Answer 1

encode_json will produce equivalent JSON to what you originally had before you decoded it with decode_json. Characters encoded using UTF-8 do not get all weird.

$ cat a.pl
use Encode   qw( encode_utf8 );
use JSON::XS qw( decode_json encode_json );

my $json = encode_utf8(qq!{"name":"\x{C9}ric" }!);
print($json, "\n");
print(encode_json(decode_json($json)), "\n");

$ perl a.pl | od -c
0000000   {   "   n   a   m   e   "   :   " 303 211   r   i   c   "    
0000020   }  \n   {   "   n   a   m   e   "   :   " 303 211   r   i   c
0000040   "   }  \n
0000043

If you want a parser that preserves the original JSON, you’ll surely have to write your own; the existing ones don’t do that.