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# Copyright 2018 New Vector Ltd
#
# 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.
import logging
import re
import typing
if typing.TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
# it's unclear what the maximum length of an email address is. RFC3696 (as corrected
# by errata) says:
# the upper limit on address lengths should normally be considered to be 254.
#
# In practice, mail servers appear to be more tolerant and allow 400 characters
# or so. Let's allow 500, which should be plenty for everyone.
#
MAX_EMAIL_ADDRESS_LENGTH = 500
def check_3pid_allowed(hs: "HomeServer", medium: str, address: str) -> bool:
"""Checks whether a given format of 3PID is allowed to be used on this HS
Args:
hs: server
medium: 3pid medium - e.g. email, msisdn
address: address within that medium (e.g. "wotan@matrix.org")
msisdns need to first have been canonicalised
Returns:
bool: whether the 3PID medium/address is allowed to be added to this HS
"""
if hs.config.allowed_local_3pids:
for constraint in hs.config.allowed_local_3pids:
logger.debug(
"Checking 3PID %s (%s) against %s (%s)",
address,
medium,
constraint["pattern"],
constraint["medium"],
)
if medium == constraint["medium"] and re.match(
constraint["pattern"], address
):
return True
else:
return True
return False
def canonicalise_email(address: str) -> str:
"""'Canonicalise' email address
Case folding of local part of email address and lowercase domain part
See MSC2265, https://github.com/matrix-org/matrix-doc/pull/2265
Args:
address: email address to be canonicalised
Returns:
The canonical form of the email address
Raises:
ValueError if the address could not be parsed.
"""
address = address.strip()
parts = address.split("@")
if len(parts) != 2:
logger.debug("Couldn't parse email address %s", address)
raise ValueError("Unable to parse email address")
return parts[0].casefold() + "@" + parts[1].lower()
def validate_email(address: str) -> str:
"""Does some basic validation on an email address.
Returns the canonicalised email, as returned by `canonicalise_email`.
Raises a ValueError if the email is invalid.
"""
# First we try canonicalising in case that fails
address = canonicalise_email(address)
# Email addresses have to be at least 3 characters.
if len(address) < 3:
raise ValueError("Unable to parse email address")
if len(address) > MAX_EMAIL_ADDRESS_LENGTH:
raise ValueError("Unable to parse email address")
return address
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