forked from karolyi/py3-validate-email
66 lines
2.2 KiB
Python
66 lines
2.2 KiB
Python
from dns.exception import Timeout
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from dns.rdatatype import MX as rdtype_mx
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from dns.rdtypes.ANY.MX import MX
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from dns.resolver import (
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NXDOMAIN, YXDOMAIN, Answer, NoAnswer, NoNameservers, resolve)
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from .constants import HOST_REGEX
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from .email_address import EmailAddress
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from .exceptions import (
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DNSConfigurationError, DNSTimeoutError, DomainNotFoundError, NoMXError,
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NoNameserverError, NoValidMXError)
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def _get_mx_records(domain: str, timeout: float) -> Answer:
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'Return the DNS response for checking, optionally raise exceptions.'
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try:
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return resolve(
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qname=domain, rdtype=rdtype_mx, lifetime=timeout,
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search=True)
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except NXDOMAIN:
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raise DomainNotFoundError
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except NoNameservers:
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raise NoNameserverError
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except Timeout:
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raise DNSTimeoutError
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except YXDOMAIN:
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raise DNSConfigurationError
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except NoAnswer:
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raise NoMXError
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def _get_cleaned_mx_records(domain: str, timeout: float) -> list:
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"""
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Return a list of hostnames in the MX record, raise an exception on
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any issues.
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"""
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answer = _get_mx_records(domain=domain, timeout=timeout)
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to_check = list()
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host_set = set()
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for record in answer.rrset.processing_order(): # type: MX
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dns_str = record.exchange.to_text().rstrip('.') # type: str
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if dns_str in host_set:
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continue
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to_check.append(dns_str)
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host_set.add(dns_str)
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result = [x for x in to_check if HOST_REGEX.search(string=x)]
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if not result:
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raise NoValidMXError
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return result
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def dns_check(email_address: EmailAddress, timeout: float = 10) -> list:
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"""
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Check whether there are any responsible SMTP servers for the email
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address by looking up the DNS MX records.
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In case no responsible SMTP servers can be determined, a variety of
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exceptions is raised depending on the exact issue, all derived from
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`MXError`. Otherwise, return the list of MX hostnames.
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"""
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if email_address.domain_literal_ip:
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return [email_address.domain_literal_ip]
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else:
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return _get_cleaned_mx_records(
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domain=email_address.domain, timeout=timeout)
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