cti-python-stix2/stix2/utils.py

33 lines
894 B
Python

"""Utility functions and classes for the stix2 library."""
import datetime as dt
import pytz
# Sentinel value for fields that should be set to the current time.
# We can't use the standard 'default' approach, since if there are multiple
# timestamps in a single object, the timestamps will vary by a few microseconds.
NOW = object()
def get_timestamp():
return dt.datetime.now(tz=pytz.UTC)
def format_datetime(dttm):
# 1. Convert to timezone-aware
# 2. Convert to UTC
# 3. Format in ISO format
# 4. Add subsecond value if non-zero
# 5. Add "Z"
try:
zoned = dttm.astimezone(pytz.utc)
except ValueError:
# dttm is timezone-naive; assume UTC
pytz.utc.localize(dttm)
ts = zoned.strftime("%Y-%m-%dT%H:%M:%S")
if zoned.microsecond > 0:
ms = zoned.strftime("%f")
ts = ts + '.' + ms.rstrip("0")
return ts + "Z"