<?php

    // Generate nonce string
    $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $nonce = '';
    for($i=1; $i <= 32; $i++)
    {
        $pos = mt_rand(0, strlen($chars) - 1);
        $char = $chars[$pos];
        $nonce .= $char;
    }
    $ch = curl_init();
    $timestamp = round(microtime(true) * 1000);
    // Request body
     $request = array(
       "env" => array(
             "terminalType" => "APP"
          ),
       "merchantTradeNo" => mt_rand(982538,9825382937292),
       "orderAmount" => 25.17,
       "currency" => "BUSD",
       "goods" => array(
                "goodsType" => "01",
                "goodsCategory" => "D000",
                "referenceGoodsId" => "7876763A3B",
                "goodsName" => "Ice Cream",
                "goodsDetail" => "Greentea ice cream cone"
             )
    );

    $json_request = json_encode($request);
...................................................................
......................................
.....................