Last active
May 7, 2024 08:39
-
-
Save chengkiang/7e1c4899768245570cc49c7d23bc394c to your computer and use it in GitHub Desktop.
SG PayNow QR Code Generator Sample
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
String.prototype.padLeft = function (n, str) { | |
if (n < String(this).length) { | |
return this.toString(); | |
} | |
else { | |
return Array(n - String(this).length + 1).join(str || '0') + this; | |
} | |
} | |
function crc16(s) { | |
var crcTable = [0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, | |
0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b, | |
0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210, | |
0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, | |
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, | |
0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401, | |
0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, | |
0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, | |
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, | |
0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, | |
0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5, | |
0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, | |
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, | |
0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, | |
0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc, | |
0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, | |
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, | |
0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd, | |
0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, | |
0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, | |
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, | |
0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, | |
0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1, | |
0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, | |
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, | |
0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2, | |
0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb, | |
0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, | |
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, | |
0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8, | |
0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, | |
0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, | |
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, | |
0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, | |
0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c, | |
0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, | |
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, | |
0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, | |
0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07, | |
0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, | |
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, | |
0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74, | |
0x2e93, 0x3eb2, 0x0ed1, 0x1ef0]; | |
var crc = 0xFFFF; | |
var j, i; | |
for (i = 0; i < s.length; i++) { | |
c = s.charCodeAt(i); | |
if (c > 255) { | |
throw new RangeError(); | |
} | |
j = (c ^ (crc >> 8)) & 0xFF; | |
crc = crcTable[j] ^ (crc << 8); | |
} | |
return ((crc ^ 0) & 0xFFFF).toString(16).toUpperCase().padStart(4, '0'); | |
} | |
function generatePayNowStr( opts ) { | |
const p = [ | |
{ id: '00', value: '01' }, // ID 00: Payload Format Indicator (Fixed to '01') | |
{ id: '01', value: '12' }, // ID 01: Point of Initiation Method 11: static, 12: dynamic | |
{ | |
id: '26', value: // ID 26: Merchant Account Info Template | |
[{ id: '00', value: 'SG.PAYNOW' }, | |
{ id: '01', value: '2' }, // 0 for mobile, 2 for UEN. 1 is not used. | |
{ id: '02', value: opts.uen }, // PayNow UEN (Company Unique Entity Number) | |
{ id: '03', value: opts.editable.toString() }, // 1 = Payment amount is editable, 0 = Not Editable | |
{ id: '04', value: opts.expiry }] // Expiry date (YYYYMMDD) | |
}, | |
{ id: '52', value: '0000' }, // ID 52: Merchant Category Code (not used) | |
{ id: '53', value: '702' }, // ID 53: Currency. SGD is 702 | |
{ id: '54', value: opts.amount.toString() }, // ID 54: Transaction Amount | |
{ id: '58', value: 'SG' }, // ID 58: 2-letter Country Code (SG) | |
{ id: '59', value: 'COMPANY NAME' }, // ID 59: Company Name | |
{ id: '60', value: 'Singapore' }, // ID 60: Merchant City | |
{ | |
id: '62', value: [{ // ID 62: Additional data fields | |
id: '01', value: opts.refNumber // ID 01: Bill Number | |
}] | |
} | |
] | |
let str = p.reduce((final, current) => { | |
if (Array.isArray(current.value)) { //nest loop | |
current.value = current.value.reduce((f, c) => { | |
f += c.id + c.value.length.toString().padLeft(2) + c.value; | |
return f | |
}, "") | |
} | |
final += current.id + current.value.length.toString().padLeft(2) + current.value; | |
return final | |
}, "") | |
// Here we add "6304" to the previous string | |
// ID 63 (Checksum) 04 (4 characters) | |
// Do a CRC16 of the whole string including the "6304" | |
// then append it to the end. | |
str += '6304' + crc16(str + '6304'); | |
return str; | |
} |
May I know can we limit a qr code for one transaction only? For example, once a user has scanned the QR code and paid, the QR code is expired and doesn't allow transaction anymore.
May I know can we limit a qr code for one transaction only? For example, once a user has scanned the QR code and paid, the QR code is expired and doesn't allow transaction anymore.
You need bank transaction API access for that.. The QR code has no way to know if it was even scanned at all... :)
I see, thank you for the answer.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
I just tested and it works with the following:
If you are using a mobile number instead of a company UEN, you need to change line #80 of the gist to:
and also make sure it's a valid mobile number. If you put in a fake number, it won't work.
By the way, I noticed in your comment that your date is in the year 2023.