QDnsLookup¶

PyQt5.QtNetwork.QDnsLookup: Inherits from QObject.

Description¶

The QDnsLookup class represents a DNS lookup.

QDnsLookup uses the mechanisms provided by the operating system to perform DNS lookups. To perform a lookup you need to specify a name() and type() then invoke the lookup() slot. The finished signal will be emitted upon completion.

For example, you can determine which servers an XMPP chat client should connect to for a given domain with:

# void MyObject::lookupServers()
# {
#     // Create a DNS lookup.
#     dns = new QDnsLookup(this);
#     connect(dns, SIGNAL(finished()),
#             this, SLOT(handleServers()));

#     // Find the XMPP servers for gmail.com
#     dns->setType(QDnsLookup::SRV);
#     dns->setName("_xmpp-client._tcp.gmail.com");
#     dns->lookup();
# }

Once the request finishes you can handle the results with:

# void MyObject::handleServers()
# {
#     // Check the lookup succeeded.
#     if (dns->error() != QDnsLookup::NoError) {
#         qWarning("DNS lookup failed");
#         dns->deleteLater();
#         return;
#     }

#     // Handle the results.
#     const auto records = dns->serviceRecords();
#     for (const QDnsServiceRecord &record : records) {
#         ...
#     }
#     dns->deleteLater();
# }

Note: If you simply want to find the IP address(es) associated with a host name, or the host name associated with an IP address you should use QHostInfo instead.

Enums¶

Error

Indicates all possible error conditions found during the processing of the DNS lookup.

Member	Value	Description
InvalidReplyError	4	the reply returned by the server was invalid.
InvalidRequestError	3	the requested DNS lookup was invalid.
NoError	0	no error condition.
NotFoundError	7	the requested domain name does not exist (NXDOMAIN).
OperationCancelledError	2	the lookup was aborted using the abort() method.
ResolverError	1	there was an error initializing the system’s DNS resolver.
ServerFailureError	5	the server encountered an internal failure while processing the request (SERVFAIL).
ServerRefusedError	6	the server refused to process the request for security or policy reasons (REFUSED).

Type

TODO

Member	Value	Description
A	TODO	TODO
AAAA	TODO	TODO
ANY	TODO	TODO
CNAME	TODO	TODO
MX	TODO	TODO
NS	TODO	TODO
PTR	TODO	TODO
SRV	TODO	TODO
TXT	TODO	TODO

Methods¶

__init__(parent: QObject = None): TODO

__init__(Type, str, parent: QObject = None): TODO

__init__(Type, str, Union[QHostAddress, SpecialAddress], parent: QObject = None): TODO

abort()

Aborts the DNS lookup operation.

If the lookup is already finished, does nothing.

canonicalNameRecords() → List[QDnsDomainNameRecord]: Returns the list of canonical name records associated with this lookup.

error() → Error: TODO

errorString() → str: TODO

hostAddressRecords() → List[QDnsHostAddressRecord]: Returns the list of host address records associated with this lookup.

isFinished() → bool: Returns whether the reply has finished or was aborted.

lookup()

Performs the DNS lookup.

The finished signal is emitted upon completion.

mailExchangeRecords() → List[QDnsMailExchangeRecord]

Returns the list of mail exchange records associated with this lookup.

The records are sorted according to RFC 5321, so if you use them to connect to servers, you should try them in the order they are listed.

name() → str: See also

setName().

nameserver() → QHostAddress: See also

setNameserver().

nameServerRecords() → List[QDnsDomainNameRecord]: Returns the list of name server records associated with this lookup.

pointerRecords() → List[QDnsDomainNameRecord]: Returns the list of pointer records associated with this lookup.

serviceRecords() → List[QDnsServiceRecord]

Returns the list of service records associated with this lookup.

The records are sorted according to RFC 2782, so if you use them to connect to servers, you should try them in the order they are listed.

setName(str): See also

name().

setNameserver(Union[QHostAddress, SpecialAddress]): See also

nameserver().

setType(Type): TODO

textRecords() → List[QDnsTextRecord]: Returns the list of text records associated with this lookup.

type() → Type: See also

setType().

Signals¶

finished(): TODO

nameChanged(str): TODO

nameserverChanged(Union[QHostAddress, SpecialAddress]): TODO

typeChanged(Type): TODO