How to iterate over the "params" of an item ZOO Joomla?

Question

The item of my interest is in the __zoo_item table. My query:

$query
    ->select($db->quoteName(array('params')))
    ->from($db->quoteName('#__zoo_item'));

$db->setQuery($query);
$resultado = $db->loadObjectList();

The contents of params is a JSON like this:

 {
    "metadata.title": "",
    "metadata.description": "",
    "metadata.keywords": "",
    "metadata.robots": "",
    "metadata.author": "",
    "config.enable_comments": "0",
    "config.primary_category": "27"
}

I need to retrieve the value of primary_category. That is, I need retrieve: 27. How do I do that? I try to recover it as follows:

foreach ($resultado as value) {
    if ( is_object($value) ) {
        echo $value->config.primary_category;
    }
}

This is the best way to do this? The browser returns this: primary_category. How to retrieve the value: 27?

Answer 1

ZOO syntax is a bit different. Check this out: http://yootheme.com/zoo/documentation/developers/accessing-element-data

Answer 2

I don't think your code is the canonical way to access ZOO parameter values, but using your method you probably want something like:

$value = json_decode($value);
$primary_category = $value->{'config.primary_category'});

Answer 3

The dot in property name is causing the issue. Multiple ways to solve it:

1. Assign property name to a variable:

   $value = json_decode($value);
   
   $property = 'config.primary_category';
   
   echo $value->$property;
   

2. Enclose property value in curly brackets:

   $value = json_decode($value);
   
   echo $value->{'config.primary_category'};
   

3. Turn params into Registry object (this is the Joomla way):

   use Joomla\Registry\Registry;
   
   $value = new Registry($value);
   
   echo $value->get('config.primary_category');