firebase-admin-python/firebase_admin/_rfc3339.py at ssrc-update · inlined/firebase-admin-python · GitHub

History

87 lines (72 loc) · 3.11 KB

Raw

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

# http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""Parse RFC3339 date strings"""

from datetime import datetime, timezone

import re

def parse_to_epoch(datestr):

"""Parse an RFC3339 date string and return the number of seconds since the

epoch (as a float).

In particular, this method is meant to parse the strings returned by the

JSON mapping of protobuf google.protobuf.timestamp.Timestamp instances:

https://github.com/protocolbuffers/protobuf/blob/4cf5bfee9546101d98754d23ff378ff718ba8438/src/google/protobuf/timestamp.proto#L99

This method has microsecond precision; nanoseconds will be truncated.

Args:

datestr: A string in RFC3339 format.

Returns:

Float: The number of seconds since the Unix epoch.

Raises:

ValueError: Raised if the `datestr` is not a valid RFC3339 date string.

"""

return _parse_to_datetime(datestr).timestamp()

def _parse_to_datetime(datestr):

"""Parse an RFC3339 date string and return a python datetime instance.

Args:

datestr: A string in RFC3339 format.

Returns:

datetime: The corresponding `datetime` (with timezone information).

Raises:

ValueError: Raised if the `datestr` is not a valid RFC3339 date string.

"""

# If more than 6 digits appear in the fractional seconds position, truncate

# to just the most significant 6. (i.e. we only have microsecond precision;

# nanos are truncated.)

datestr_modified = re.sub(r'(\.\d{6})\d*', r'\1', datestr)

# This format is the one we actually expect to occur from our backend. The

# others are only present because the spec says we *should* accept them.

try:

return datetime.strptime(

datestr_modified, '%Y-%m-%dT%H:%M:%S.%fZ'

).replace(tzinfo=timezone.utc)

except ValueError:

pass

try:

return datetime.strptime(

datestr_modified, '%Y-%m-%dT%H:%M:%SZ'

).replace(tzinfo=timezone.utc)

except ValueError:

pass

# Note: %z parses timezone offsets, but requires the timezone offset *not*

# include a separating ':'. As of python 3.7, this was relaxed.

# TODO(rsgowman): Once python3.7 becomes our floor, we can drop the regex

# replacement.

datestr_modified = re.sub(r'(\d\d):(\d\d)$', r'\1\2', datestr_modified)

try:

return datetime.strptime(datestr_modified, '%Y-%m-%dT%H:%M:%S.%f%z')

except ValueError:

pass

try:

return datetime.strptime(datestr_modified, '%Y-%m-%dT%H:%M:%S%z')

except ValueError:

pass

raise ValueError('time data {0} does not match RFC3339 format'.format(datestr))

firebase-admin-python/firebase_admin/_rfc3339.py at ssrc-update · inlined/firebase-admin-python · GitHub

Expand file tree

Breadcrumbs

_rfc3339.py

Latest commit

History

Breadcrumbs

_rfc3339.py

File metadata and controls