Class Answer

dns/resolver.py:247–314

DNS stub resolver answer. Instances of this class bundle up the result of a successful DNS resolution. For convenience, the answer object implements much of the sequence protocol, forwarding to its ``rrset`` attribute. E.g. ``for a in answer`` is equivalent to ``for a in answe

class Answer:
    """DNS stub resolver answer.

    Instances of this class bundle up the result of a successful DNS
    resolution.

    For convenience, the answer object implements much of the sequence
    protocol, forwarding to its ``rrset`` attribute.  E.g.
    ``for a in answer`` is equivalent to ``for a in answer.rrset``.
    ``answer[i]`` is equivalent to ``answer.rrset[i]``, and
    ``answer[i:j]`` is equivalent to ``answer.rrset[i:j]``.

    Note that CNAMEs or DNAMEs in the response may mean that answer
    RRset's name might not be the query name.
    """

    def __init__(
        self,
        qname: dns.name.Name,
        rdtype: dns.rdatatype.RdataType,
        rdclass: dns.rdataclass.RdataClass,
        response: dns.message.QueryMessage,
        nameserver: str | None = None,
        port: int | None = None,
    ) -> None:
        self.qname = qname
        self.rdtype = rdtype
        self.rdclass = rdclass
        self.response = response
        self.nameserver = nameserver
        self.port = port
        self.chaining_result = response.resolve_chaining()
        # Copy some attributes out of chaining_result for backwards
        # compatibility and convenience.
        self.canonical_name = self.chaining_result.canonical_name
        self.rrset = self.chaining_result.answer
        self.expiration = time.time() + self.chaining_result.minimum_ttl

    def __getattr__(self, attr):  # pragma: no cover
        if self.rrset is not None:
            if attr == "name":
                return self.rrset.name
            elif attr == "ttl":
                return self.rrset.ttl
            elif attr == "covers":
                return self.rrset.covers
            elif attr == "rdclass":
                return self.rrset.rdclass
            elif attr == "rdtype":
                return self.rrset.rdtype
        else:
            raise AttributeError(attr)

    def __len__(self) -> int:
        return self.rrset is not None and len(self.rrset) or 0

    def __iter__(self) -> Iterator[Any]:
        return self.rrset is not None and iter(self.rrset) or iter(tuple())