Windows NT/2000/XP printer spool file
application/octet-stream
Magic Bytes
Offset: 0
00 00 01
The Windows NT/2000/XP printer spool file is a temporary data format developed by Microsoft for managing document queues within the Windows Print Spooler service. It stores raw printer commands or graphical data, enabling the operating system to process print jobs in the background while users continue working in other applications. Now considered a legacy format, these files are generally safe but may contain sensitive information from the documents they were originally intended to print.
Validation Code
How to validate .spl files in Python
Python
def is_spl(file_path: str) -> bool:
"""Check if file is a valid SPL by magic bytes."""
signature = bytes([0x00, 0x00, 0x01])
with open(file_path, "rb") as f:
return f.read(3) == signatureHow to validate .spl files in Node.js
Node.js
function isSPL(buffer: Buffer): boolean {
const signature = Buffer.from([0x00, 0x00, 0x01]);
return buffer.subarray(0, 3).equals(signature);
}
Go
func IsSPL(data []byte) bool {
signature := []byte{0x00, 0x00, 0x01}
if len(data) < 3 {
return false
}
return bytes.Equal(data[:3], signature)
}API Endpoint
GET
/api/v1/spl
curl https://filesignature.org/api/v1/spl