upsert-item-catalog.php

<?php
$api_instance = new SquareConnect\Api\CatalogApi();
$body = array(
  'idempotency_key'=>uniqid(),
  'object'=>array(
    'type'=>'ITEM',
    'id'=>'#temp-item-id',
    'item_data'=>array(
      'name'=>'Brass Tube',
      'description'=>'Great for models',
      'variations'=>array(
        array(
          'type'=>'ITEM_VARIATION',
          'id'=>'#var0',
          'item_variation_data'=>array(
            'item_id'=>'#temp-item-id',
            'name'=>'15 cm',
            'pricing_type'=>'VARIABLE_PRICING'
          )
        ),
        array(
          'type'=>'ITEM_VARIATION',
          'id'=>'#var1',
          'item_variation_data'=>array(
            'item_id'=>'#temp-item-id',
            'name'=>'30 cm',
            'pricing_type'=>'VARIABLE_PRICING'
          )
        )
      )
    )
  )
);

$result = $api_instance->upsertCatalogObject($body);