在PHP对象中显示键/值

In PHP, how can I make this data:

{
   "items": {
     "item": [{
           "id": "59",
           "type": "Domain",
           "relid": "27",
           "description": "Sample Monthly Product(01\ / 01\ / 2016 - 31\ / 01\ / 2016)",
           "amount": "180.00",
           "taxed": "0"
      }]
   }
}

Have this format:

{
  "items[item][0][id]": "59",
  "items[item][0][type]": "Domain",
  "items[item][0][relid]": "27",
  "items[item][0][description]": "Sample Monthly Product (01\/01\/2016 - 31\/01\/2016)",
  "items[item][0][amount]": "180.00",
  "items[item][0][taxed]": "0"
}

Reason: Setting up a Zap (via Zapier) using email parser to import invoices from WHMCS, and it seems to work with parsing data when 2nd format (items[item][0][id]) to read the line descriptions but not when using the 1st. In the WHMCS API ref it shows it outputting as the 2nd format but can't see why mine looks like 1st (developers.whmcs.com/api-reference/getinvoice)

I think this might work with your current setup:

<?php

//assuming your current dataset isn't in JSON, you can ignore this part
$json = '{
   "items": {
     "item": [{
           "id": "59",
           "type": "Domain",
           "relid": "27",
           "description": "Sample Monthly Product",
           "amount": "180.00",
           "taxed": "0"
      },
      {
           "id": "203",
           "type": "Server",
           "relid": "86",
           "description": "Sample Yearly Product",
           "amount": "290.00",
           "taxed": "1"
      }]
   }
}';

$json = json_decode($json, true);

$parsed = array();

foreach ($json['items']['item'] as $index => $item)
    foreach ($item as $attr => $val)
        $parsed['items[item][' . $index . '][' . $attr . ']'] = $val;

echo json_encode($parsed);

Output:

{
    "items[item][0][id]": "59",
    "items[item][0][type]": "Domain",
    "items[item][0][relid]": "27",
    "items[item][0][description]": "Sample Monthly Product",
    "items[item][0][amount]": "180.00",
    "items[item][0][taxed]": "0",
    "items[item][1][id]": "203",
    "items[item][1][type]": "Server",
    "items[item][1][relid]": "86",
    "items[item][1][description]": "Sample Yearly Product",
    "items[item][1][amount]": "290.00",
    "items[item][1][taxed]": "1"
}