twisted.mail.relaymanager.MXCalculator : API documentation

Instance Variable	clock	A reactor which will be used to schedule timeouts. (type: `IReactorTime` provider)
Instance Variable	resolver	A resolver. (type: `IResolver`)
Instance Variable	badMXs	A mapping of non-functioning mail exchange hostname to time at which another attempt at contacting it may be made. (type: `dict` mapping `bytes` to `float`)
Instance Variable	timeOutBadMX	Period in seconds between attempts to contact a non-functioning mail exchange host. (type: `int`)
Instance Variable	fallbackToDomain	A flag indicating whether to attempt to use the hostname directly when no mail exchange can be found (`True`) or not (`False`). (type: `bool`)
Method	__init__
Method	markBad	Record that a mail exchange host is not currently functioning.
Method	markGood	Record that a mail exchange host is functioning.
Method	getMX	Find the name of a host that acts as a mail exchange server for a domain.
Method	_filterRecords	Organize the records of a DNS response by record name.
Method	_cbMX	Try to find the mail exchange host for a domain from the given DNS records.
Method	_ebMX	Attempt to use the name of the domain directly when mail exchange lookup fails.

badMXs =

A mapping of non-functioning mail exchange hostname to time at which another attempt at contacting it may be made. (type: dict mapping bytes to float)

fallbackToDomain =

A flag indicating whether to attempt to use the hostname directly when no mail exchange can be found (True) or not (False). (type: bool)

def getMX(self, domain, maximumCanonicalChainLength=3): (source)

Find the name of a host that acts as a mail exchange server for a domain.

Parameters	domain	A domain name. (type: `bytes`)
	maximumCanonicalChainLength	The maximum number of unique canonical name records to follow while looking up the mail exchange host. (type: `int`)
Returns	A deferred which succeeds with the MX record for the mail exchange server for the domain or fails if none can be found. (type: `Deferred` which successfully fires with `Record_MX`)

def _filterRecords(self, records): (source)

Organize the records of a DNS response by record name.

Parameters	records	Answer resource records, authority resource records and additional resource records. (type: 3-`tuple` of (0) `list` of `RRHeader`, (1) `list` of `RRHeader`, (2) `list` of `RRHeader`)
Returns	A mapping of record name to record payload. (type: `dict` mapping `bytes` to `list` of `IRecord` provider)

def _cbMX(self, answers, domain, cnamesLeft): (source)

Try to find the mail exchange host for a domain from the given DNS records.

This will attempt to resolve canonical name record results. It can recognize loops and will give up on non-cyclic chains after a specified number of lookups.

Parameters	answers	A mapping of record name to record payload. (type: `dict` mapping `bytes` to `list` of `IRecord` provider)
	domain	A domain name. (type: `bytes`)
	cnamesLeft	The number of unique canonical name records left to follow while looking up the mail exchange host. (type: `int`)
Returns	An MX record for the mail exchange host or a failure if one cannot be found. (type: `Record_MX` or `Failure`)

def _ebMX(self, failure, domain): (source)

Attempt to use the name of the domain directly when mail exchange lookup fails.

Parameters	failure	The reason for the lookup failure. (type: `Failure`)
	domain	The domain name. (type: `bytes`)
Returns	An MX record for the domain or a failure if the fallback to domain option is not in effect and an error, other than not finding an MX record, occured during lookup. (type: `Record_MX` or `Failure`)
Raises	IOError	When no MX record could be found and the fallback to domain option is not in effect.
	DNSLookupError	When no MX record could be found and the fallback to domain option is in effect but no address for the domain could be found.

Parameters	A resolver.
	clock	A reactor which will be used to schedule timeouts. (type: `IReactorTime` provider or `NoneType`)

t.m.r.MXCalculator : class documentation