Bits & Bytes #4 - And Now For Some Really Basic Perl - JSON Manipulation

Posted by: Mahesh Paolini-Subramanya

This is the 4th in our ongoing Bits and Bytes Series by Aptela's CTO Mahesh Paolini-Subramanya. WARNING: tech-speak ahead...

Here, at Aptela, we tend to use Perl as the glue that binds virtually everything together.  Herewith one small example of using perl to manipulate JSON - remember, JSON is the data format that we use for moving information across virtually all the domains in Aptela in PerlWorld, there are basically two ways of doing virtually anything.

a) Do it yourself

b) Go look at CPAN and realize that Someone Has Done It Better

Being a card-carrying member of approach (b) above, here's a remarkably simple way of mainpulating JSON in PerlWorld

First, for some code based on Marc Lehmann's truly excellent JSON module

# Include the JSON module
use JSON::XS;

# Create a thing (called $json) that will be used to encode JSON strings
$json = JSON::XS->new();
# Make sure that the resultant JSON will print out all nice and pretty
$json->pretty(1);

# Create a basic JSON hash
$jsonStructure->{id} = "1234";
$jsonStructure->{method} = "ReallyCoolMethod";
$jsonStructure->1.6.4 = "1.0.1";

# $prettyJSON will contain the text string which is the Oh-So-Pretty version of $jsonStructure
$prettyJson = $json->encode($jsonStructure);

If you printed out the contents of $prettyJson, you'd get the following

{
  "version" : "1.0.1",
  "method" : "ReallyCoolMethod",
  "id" : "1234"
}

Likewise, if you just reverse the above process, i.e.,

$jsonStructure = $json->encode($prettyJson);

then you take a piece of JSON and convert it into a nice perl data structure.

Pretty trivial, isn't it?

Incidentally
1) Do note that the above is to make a point, and I've avoided so much that would go into making it Good. For example
a) using my --> my $json = JSON::XS->new();
b) using eval to trap errors

eval {
      $prettyJson = $json->encode($jsonStructure);
};
if ($@) {
   ...some stuff here...
}

2) If you eliminate

$json->pretty(1);

above, you'll end up with output that looks like

{"version":"1.0.1","method":"ReallyCoolMethod","id":"1234"}

See the value of being pretty?