parse data from JSON callback using PHP - php

Question

I receive a callback data from payment site and try to save some values into txt file
Getting an array:
$json = file_get_contents('php://input');
$obj = json_decode($json,true);
Saving all data to txt:
file_put_contents('robot.php', var_export($obj, true) . "\r\n\r\n", FILE_APPEND | LOCK_EX);
The result from txt:
array (
'rrn' => '',
'masked_card' => '444455XXXXXX1111',
'sender_cell_phone' => '',
'response_status' => 'success',
'sender_account' => '',
'fee' => '',
'rectoken_lifetime' => '',
'reversal_amount' => '0',
'settlement_amount' => '0',
'actual_amount' => '370000',
'order_status' => 'approved',
'response_description' => '',
'verification_status' => '',
'order_time' => '04.01.2018 21:53:47',
'actual_currency' => 'JPY',
'order_id' => 1515095627',
'parent_order_id' => '',
'merchant_data' => '[{"name":"custom-field-0","label":"fist_name","value":"john_doe"},{"name":"custom-field-2","label":"phone","value":"07777777777"}]',
'tran_type' => 'purchase',
'eci' => '5',
'settlement_date' => '',
'payment_system' => 'card',
'rectoken' => '',
'approval_code' => '56783909',
'merchant_id' => 14066776208,
'settlement_currency' => '',
'payment_id' => 7487818gg3,
'product_id' => '',
'amount' => '370000',
'sender_email' => 'admin#none.in.ua',
)
How to save in txt separate values from nested array 'merchant_data' - first name and phone?

Answer 1

You can make new array and save it to file:
$json = file_get_contents('php://input');
$obj = json_decode($json,true);
$save = [];
foreach ($obj['merchant_data'] as $data){
$save[] = [
'name' => $data['first_name'],
'phone' => $data['phone'],
];
}
file_put_contents('robot.php', var_export($save, true) . "\r\n\r\n", FILE_APPEND | LOCK_EX);