micropython-samples/ntptime/ntptime.py

42 wiersze
1.5 KiB
Python

# Adapted from official ntptime by Peter Hinch July 2022
# The main aim is portability:
# Detects host device's epoch and returns time relative to that.
# Basic approach to local time: add offset in hours relative to UTC.
# Timeouts return a time of 0. These happen: caller should check for this.
# Replace socket timeout with select.poll as per docs:
# http://docs.micropython.org/en/latest/library/socket.html#socket.socket.settimeout
import socket
import struct
import select
from time import gmtime
# (date(2000, 1, 1) - date(1900, 1, 1)).days * 24*60*60
# (date(1970, 1, 1) - date(1900, 1, 1)).days * 24*60*60
NTP_DELTA = 3155673600 if gmtime(0)[0] == 2000 else 2208988800
# The NTP host can be configured at runtime by doing: ntptime.host = 'myhost.org'
host = "pool.ntp.org"
def time(hrs_offset=0): # Local time offset in hrs relative to UTC
NTP_QUERY = bytearray(48)
NTP_QUERY[0] = 0x1B
try:
addr = socket.getaddrinfo(host, 123)[0][-1]
except OSError:
return 0
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
poller = select.poll()
poller.register(s, select.POLLIN)
try:
s.sendto(NTP_QUERY, addr)
if poller.poll(1000): # time in milliseconds
msg = s.recv(48)
val = struct.unpack("!I", msg[40:44])[0] # Can return 0
return max(val - NTP_DELTA + hrs_offset * 3600, 0)
except OSError:
pass # LAN error
finally:
s.close()
return 0 # Timeout or LAN error occurred