Is there a way to encode object constructors with the JSON Perl Module?

Question

All,

I'm using the JSON Perl module to encode JSON.

I'd like the resulting JSON to include lines like this:

{
   "startDate": new Date(2010,11,15,0,0),
   "aString"  : "String Data",
   "aNumber"  : 1234
}

In order to create that, I have a Perl HASHREF like this:

{
   startDate => SEE BELOW,
   aString   => "String Data",
   aNumber   => 1234,
}

Here's my problem: I can't figure out how to coerce the JSON module into printing unquoted strings, so that I can include my new Date(...) instantiation call. I've tried creating a Perl module with a TO_JSON method, but the output still gets quoted.

Does anybody out there have any suggestions on how I can encourage JSON to print unquoted strings?

score 7 · Accepted Answer · answered Nov 15 '10 at 20:06

7

JSON is not meant to encode objects like that. It encodes simple data structures like arrays and hashes. If you then want to use that deserialized data to populate a blessed object, you need to add another layer on top.

For Moose objects, the plugin MooseX::Storage is built for expressly this purpose.

answered Nov 15 '10 at 20:06

Ether

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@Bipedal: MooseX::Storage is set up to use JSON; if you're asking about something else, hop on to irc.perl.org #moose and we can help you find a solution. – Ether Nov 16 '10 at 01:13

score 3 · Answer 2 · answered Nov 15 '10 at 20:12

3

What you want is invalid in JSON. See http://www.json.org/ for what is an valid value in JSON. I'd return the date as an array and then use that in you js handler to create the Date object.

answered Nov 15 '10 at 20:12

jira

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Thanks. I'm using the Simile Timeline at [http://code.google.com/p/simile-widgets/wiki/Timeline_EventSourceJSON_jsDate]. When I reread it, I noticed the 'invalid JSON' comment... I'll rethink my approach. Thanks – Dancrumb Nov 15 '10 at 20:16

score 2 · Answer 3 · answered Nov 15 '10 at 20:08

Perhaps you should rethink your approach to this problem, say, by leaving the JSON module alone but post-processing its output? For example, come up with some convention to show that the receiver should do something special with the input:

{
   "startDate": "EVAL:new Date(2010,11,15,0,0)",
   "aString"  : "String Data",
   "aNumber"  : 1234
}

Let the receiver (Perl? JavaScript?) look for hash values that start with the keyword "EVAL:" and perform further processing on that value.

Is there a way to encode object constructors with the JSON Perl Module?

3 Answers3