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validate_email.py
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validate_email.py
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# This is from validate_email on github and is NOT my work.
# Full credit to the original author on github
# Unfortunately the code base was changed which broke all existing check code
# Hence for stability, i've added here to funclite
# RFC 2822 - style email validation for Python
# (c) 2012 Syrus Akbary <[email protected]>
# Extended from (c) 2011 Noel Bush <[email protected]>
# for support of mx and user check
# This code is made available to you under the GNU LGPL v3.
#
# This module provides a single method, valid_email_address(),
# which returns True or False to indicate whether a given address
# is valid according to the 'addr-spec' part of the specification
# given in RFC 2822. Ideally, we would like to find this
# in some other library, already thoroughly tested and well-
# maintained. The standard Python library email.utils
# contains a parse_addr() function, but it is not sufficient
# to detect many malformed addresses.
#
# This implementation aims to be faithful to the RFC, with the
# exception of a circular definition (see comments below), and
# with the omission of the pattern components marked as "obsolete".
import re
import smtplib
import logging
import socket
try:
raw_input # noqa
except NameError:
def raw_input(prompt=''):
return input(prompt)
try:
import DNS # noqa
ServerError = DNS.ServerError
DNS.DiscoverNameServers()
except (ImportError, AttributeError):
DNS = None
class ServerError(Exception):
pass
# All we are really doing is comparing the input string to one
# gigantic regular expression. But building that regexp, and
# ensuring its correctness, is made much easier by assembling it
# from the "tokens" defined by the RFC. Each of these tokens is
# tested in the accompanying unit test file.
#
# The section of RFC 2822 from which each pattern component is
# derived is given in an accompanying comment.
#
# (To make things simple, every string below is given as 'raw',
# even when it's not strictly necessary. This way we don't forget
# when it is necessary.)
#
WSP = r'[ \t]' # see 2.2.2. Structured Header Field Bodies
CRLF = r'(?:\r\n)' # see 2.2.3. Long Header Fields
NO_WS_CTL = r'\x01-\x08\x0b\x0c\x0f-\x1f\x7f' # see 3.2.1. Primitive Tokens
QUOTED_PAIR = r'(?:\\.)' # see 3.2.2. Quoted characters
FWS = r'(?:(?:' + WSP + r'*' + CRLF + r')?' + \
WSP + r'+)' # see 3.2.3. Folding white space and comments
CTEXT = r'[' + NO_WS_CTL + \
r'\x21-\x27\x2a-\x5b\x5d-\x7e]' # see 3.2.3
CCONTENT = r'(?:' + CTEXT + r'|' + \
QUOTED_PAIR + r')' # see 3.2.3 (NB: The RFC includes COMMENT here
# as well, but that would be circular.)
COMMENT = r'\((?:' + FWS + r'?' + CCONTENT + \
r')*' + FWS + r'?\)' # see 3.2.3
CFWS = r'(?:' + FWS + r'?' + COMMENT + ')*(?:' + \
FWS + '?' + COMMENT + '|' + FWS + ')' # see 3.2.3
ATEXT = r'[\w!#$%&\'\*\+\-/=\?\^`\{\|\}~]' # see 3.2.4. Atom
ATOM = CFWS + r'?' + ATEXT + r'+' + CFWS + r'?' # see 3.2.4
DOT_ATOM_TEXT = ATEXT + r'+(?:\.' + ATEXT + r'+)*' # see 3.2.4
DOT_ATOM = CFWS + r'?' + DOT_ATOM_TEXT + CFWS + r'?' # see 3.2.4
QTEXT = r'[' + NO_WS_CTL + \
r'\x21\x23-\x5b\x5d-\x7e]' # see 3.2.5. Quoted strings
QCONTENT = r'(?:' + QTEXT + r'|' + \
QUOTED_PAIR + r')' # see 3.2.5
QUOTED_STRING = CFWS + r'?' + r'"(?:' + FWS + \
r'?' + QCONTENT + r')*' + FWS + \
r'?' + r'"' + CFWS + r'?'
LOCAL_PART = r'(?:' + DOT_ATOM + r'|' + \
QUOTED_STRING + r')' # see 3.4.1. Addr-spec specification
DTEXT = r'[' + NO_WS_CTL + r'\x21-\x5a\x5e-\x7e]' # see 3.4.1
DCONTENT = r'(?:' + DTEXT + r'|' + \
QUOTED_PAIR + r')' # see 3.4.1
DOMAIN_LITERAL = CFWS + r'?' + r'\[' + \
r'(?:' + FWS + r'?' + DCONTENT + \
r')*' + FWS + r'?\]' + CFWS + r'?' # see 3.4.1
DOMAIN = r'(?:' + DOT_ATOM + r'|' + \
DOMAIN_LITERAL + r')' # see 3.4.1
ADDR_SPEC = LOCAL_PART + r'@' + DOMAIN # see 3.4.1
# A valid address will match exactly the 3.4.1 addr-spec.
VALID_ADDRESS_REGEXP = '^' + ADDR_SPEC + '$'
MX_DNS_CACHE = {}
MX_CHECK_CACHE = {}
def get_mx_ip(hostname):
if hostname not in MX_DNS_CACHE:
try:
MX_DNS_CACHE[hostname] = DNS.mxlookup(hostname) # noqa
except ServerError as e:
if e.rcode == 3: # NXDOMAIN (Non-Existent Domain)
MX_DNS_CACHE[hostname] = None
else:
raise
return MX_DNS_CACHE[hostname]
def validate_email(email, check_mx=False, verify=False, debug=False, smtp_timeout=10):
"""Indicate whether the given string is a valid email address
according to the 'addr-spec' portion of RFC 2822 (see section
3.4.1). Parts of the spec that are marked obsolete are *not*
included in this test, and certain arcane constructions that
depend on circular definitions in the spec may not pass, but in
general this should correctly identify any email address likely
to be in use as of 2011."""
if debug:
logger = logging.getLogger('validate_email')
logger.setLevel(logging.DEBUG)
else:
logger = None
try:
assert re.match(VALID_ADDRESS_REGEXP, email) is not None
check_mx |= verify
if check_mx:
if not DNS:
raise Exception('For check the mx records or check if the email exists you must '
'have installed pyDNS python package')
hostname = email[email.find('@') + 1:]
mx_hosts = get_mx_ip(hostname)
if mx_hosts is None:
return False
for mx in mx_hosts:
try:
if not verify and mx[1] in MX_CHECK_CACHE:
return MX_CHECK_CACHE[mx[1]]
smtp = smtplib.SMTP(timeout=smtp_timeout)
smtp.connect(mx[1])
MX_CHECK_CACHE[mx[1]] = True
if not verify:
try:
smtp.quit()
except smtplib.SMTPServerDisconnected:
pass
return True
status, _ = smtp.helo()
if status != 250:
smtp.quit()
if debug:
logger.debug(u'%s answer: %s - %s', mx[1], status, _)
continue
smtp.mail('')
status, _ = smtp.rcpt(email)
if status == 250:
smtp.quit()
return True
if debug:
logger.debug(u'%s answer: %s - %s', mx[1], status, _)
smtp.quit()
except smtplib.SMTPServerDisconnected: # Server not permits verify user
if debug:
logger.debug(u'%s disconected.', mx[1])
except smtplib.SMTPConnectError:
if debug:
logger.debug(u'Unable to connect to %s.', mx[1])
return None
except AssertionError:
return False
except (ServerError, socket.error) as e:
if debug:
logger.debug('ServerError or socket.error exception raised (%s).', e)
return None
return True
if __name__ == '__main__':
validate_email('[email protected]')
pass