Build/Extract PromptPay QR Code Payload in PHP for convenience payment.

PromptPay_QR_Payload.class.php

<?php

class PromptPay_QR_Payload {
	public function Generate ($ewallet_id, $amount = null, $one_time = false) {
		switch (strlen($ewallet_id)) {
			case 10:
				$ewallet_type = "01"; // Phone Number
				$ewallet_id = "0066".substr($ewallet_id, 1, 9);
				break;
			case 13:
				$ewallet_type = "02"; // ID Card
				break;
			default:
				$ewallet_type = "03"; // e-Wallet
				break;
		}
		$data = array(
			"01" => $one_time ? "12" : "11", // Point of Initiation
			"29" => array( // Merchant Account Information
				"00" => "A000000677010111", // Globally Unique Identifier
				$ewallet_type => $ewallet_id // Payment network specific
			),
			"53" => "764", // Transaction Currency
			"54" => number_format($amount, 2, ".", ""), // Transaction Amount
			"58" => "TH", // Country Code
		);
		if (is_null($amount)) unset($data["54"]);
		return self::Build($data);
	}

	public function Build ($data, $object = false) {
		if (!$object) $data = array("00" => "01") + $data + array("63" => str_repeat(" ", 4));
		$payload = "";
		foreach ($data as $key => $value) {
			if (is_array($value)) {
				$value = self::Build($value, true);
			}
			$payload .= $key;
			$payload .= sprintf("%02d", strlen($value));
			$payload .= $value;
		}
		if (!$object) $payload = trim($payload).self::GetCRC(trim($payload));
		return $payload;
	}

	public function Extract ($payload, $object = false) {
		$data = array();
		$pointer = 0;
		while ($pointer < strlen($payload)) {
			$key = substr($payload, $pointer, 2);
			$value = substr($payload, $pointer + 4, intval(substr($payload, $pointer + 2, 2)));
			if (!$object && intval($key) >= 26 && intval($key) <= 51) {
				$value = self::Extract($value, true);
			}
			$data[$key] = $value;
			$pointer += 4 + intval(substr($payload, $pointer + 2, 2));
		}
		return $data;
	}

	public function GetCRC ($data) {
		$crc = 0xFFFF;
		for ($i = 0; $i < strlen($data); $i++) {
			$x = (($crc >> 8) ^ ord($data[$i])) & 0xFF;
			$x ^= $x >> 4;
			$crc = (($crc << 8) ^ ($x << 12) ^ ($x << 5) ^ $x) & 0xFFFF;
		}
		return strtoupper(dechex($crc));
	}
}

?>