145 lines
4.1 KiB
Python
145 lines
4.1 KiB
Python
from collections import namedtuple
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from typing import Dict
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SMTPMessage = namedtuple(
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typename='SmtpErrorMessage', field_names=['command', 'code', 'text'])
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class Error(Exception):
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'Base class for all exceptions of this module.'
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message = 'Unknown error.'
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def __str__(self):
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return self.message
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class ParameterError(Error):
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"""
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Base class for all exceptions indicating a wrong function parameter.
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"""
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class FromAddressFormatError(ParameterError):
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"""
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Raised when the from email address used for the MX check has an
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invalid format.
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"""
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message = 'Invalid "From:" email address.'
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class EmailValidationError(Error):
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'Base class for all exceptions indicating validation failure.'
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class AddressFormatError(EmailValidationError):
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'Raised when the email address has an invalid format.'
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message = 'Invalid email address.'
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class DomainBlacklistedError(EmailValidationError):
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"""
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Raised when the domain of the email address is blacklisted on
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https://github.com/martenson/disposable-email-domains.
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"""
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message = 'Domain blacklisted.'
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class DNSError(EmailValidationError):
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"""
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Base class of all exceptions that indicate failure to determine a
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valid MX for the domain of email address.
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"""
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class DomainNotFoundError(DNSError):
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'Raised when the domain is not found.'
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message = 'Domain not found.'
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class NoNameserverError(DNSError):
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'Raised when the domain does not resolve by nameservers in time.'
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message = 'No nameserver found for domain.'
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class DNSTimeoutError(DNSError):
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'Raised when the domain lookup times out.'
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message = 'Domain lookup timed out.'
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class DNSConfigurationError(DNSError):
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"""
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Raised when the DNS entries for this domain are falsely configured.
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"""
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message = 'Misconfigurated DNS entries for domain.'
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class NoMXError(DNSError):
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'Raised when the domain has no MX records configured.'
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message = 'No MX record for domain found.'
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class NoValidMXError(DNSError):
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"""
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Raised when the domain has MX records configured, but none of them
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has a valid format.
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"""
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message = 'No valid MX record for domain found.'
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class SMTPError(EmailValidationError):
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"""
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Base class for exceptions raised in the end from unsuccessful SMTP
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communication.
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`error_messages` is a dictionary with a `SMTPMessage` per MX record,
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where the hostname is the key and a tuple of command, error code,
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and error message is the value.
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"""
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def __init__(self, error_messages: Dict[str, SMTPMessage]):
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self.error_messages = error_messages
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def __str__(self) -> str:
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return '\n'.join([self.message] + [
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f'{host}: {message.code} {message.text} '
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f'(in reply to {message.command!r})'
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for host, message in self.error_messages.items()
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])
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class AddressNotDeliverableError(SMTPError):
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"""
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Raised when at least one of the MX sends an SMTP reply which
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unambiguously indicate an invalid (nonexistant, blocked, expired...)
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recipient email address.
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This exception indicates that the email address is clearly invalid.
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"""
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message = 'Email address undeliverable:'
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class SMTPCommunicationError(SMTPError):
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"""
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Raised when the SMTP communication with all MX was unsuccessful for
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other reasons than an invalid recipient email address.
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This exception indicates a configuration issue either on the host
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where this program runs or on the MX. A possible reason is that the
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local host ist blacklisted on the MX.
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"""
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message = 'SMTP communication failure:'
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class SMTPTemporaryError(SMTPError):
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"""
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Raised when the email address cannot be verified because none of the
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MX gave a clear "yes" or "no" about the existence of the address,
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but at least one gave a temporary error reply to the "RCPT TO:"
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command.
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This exception indicates that the validity of the email address
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cannot be verified, either for reasons of MX configuration (like
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greylisting) or due to temporary server issues on the MX.
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"""
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message = 'Temporary error in email address verification:'
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