Question

I want to save a hash as a packed string in a db, I get the pack part down ok, but I’m having a problem getting the hash back

test hash

my $hash = {

   test_string   => 'apples,bananas,oranges',
   test_subhash  => { like => 'apples' },
   test_subarray => [ red, yellow, orange ]

}

I thought maybe I could use JSON:XS like in this example to convert the hash to a json string, and then packing the JSON string…

Thoughts on this approach?

Answer 1

Storable is capable of storing Perl structures very precisely. If you need to remember that something is a weak reference, etc, you want Storable. Otherwise, I’d avoid it.

JSON (Cpanel::JSON::XS) and YAML are good choices.

• You can have problems if you store something using one version of Storable and try to retrieve it using an earlier version. That means all machines that access the database must have the same version of Storable.
• Cpanel::JSON::XS is faster than Storable.
• A fast YAML module is probably faster than Storable.
• JSON can’t store objects, but YAML and Storable can.
• JSON and YAML are human readable (well, for some humans).
• JSON and YAML are easy to parse and generate in other languages.

Usage:

my $for_the_db = encode_json($hash);
my $hash = decode_json($from_the_db);

I don’t know what you mean by “packing”. The string produces by Cpanel::JSON::XS’s encode_json can be stored as-is into a BLOB field, while the string produced by Cpanel::JSON::XS->new->encode can be stored as-is into a TEXT field.