class QDnsLookup#

The QDnsLookup class represents a DNS lookup. More…

Synopsis#

Properties#

errorᅟ - The type of error that occurred if the DNS lookup failed, or NoError
errorStringᅟ - Human-readable description of the error if the DNS lookup failed
nameᅟ - The name to lookup
nameserverᅟ - The nameserver to use for DNS lookup
nameserverPortᅟ - The port number of nameserver to use for DNS lookup
typeᅟ - The type of DNS lookup

Methods#

def __init__()
def canonicalNameRecords()
def error()
def errorString()
def hostAddressRecords()
def isFinished()
def mailExchangeRecords()
def name()
def nameServerRecords()
def nameserver()
def nameserverPort()
def pointerRecords()
def serviceRecords()
def setName()
def setNameserver()
def setNameserverPort()
def setType()
def textRecords()
def type()

Slots#

def abort()
def lookup()

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description#

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

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:

def lookupServers(self):

    # Create a DNS lookup.
    dns = QDnsLookup(self)
    dns.finished.connect(self.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:

def handleServers(self):

    # Check the lookup succeeded.
    if dns.error() != QDnsLookup.NoError:
        qWarning("DNS lookup failed")
        dns.deleteLater()
        return

    # Handle the results.
    records = dns.serviceRecords()
    for record in 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.

class Error#

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

Constant

Description

QDnsLookup.NoError

no error condition.

QDnsLookup.ResolverError

there was an error initializing the system’s DNS resolver.

QDnsLookup.OperationCancelledError

the lookup was aborted using the abort() method.

QDnsLookup.InvalidRequestError

the requested DNS lookup was invalid.

QDnsLookup.InvalidReplyError

the reply returned by the server was invalid.

QDnsLookup.ServerFailureError

the server encountered an internal failure while processing the request (SERVFAIL).

QDnsLookup.ServerRefusedError

the server refused to process the request for security or policy reasons (REFUSED).

QDnsLookup.NotFoundError

the requested domain name does not exist (NXDOMAIN).

QDnsLookup.TimeoutError

the server was not reached or did not reply in time (since 6.6).

Constant	Description
QDnsLookup.NoError	no error condition.
QDnsLookup.ResolverError	there was an error initializing the system’s DNS resolver.
QDnsLookup.OperationCancelledError	the lookup was aborted using the `abort()` method.
QDnsLookup.InvalidRequestError	the requested DNS lookup was invalid.
QDnsLookup.InvalidReplyError	the reply returned by the server was invalid.
QDnsLookup.ServerFailureError	the server encountered an internal failure while processing the request (SERVFAIL).
QDnsLookup.ServerRefusedError	the server refused to process the request for security or policy reasons (REFUSED).
QDnsLookup.NotFoundError	the requested domain name does not exist (NXDOMAIN).
QDnsLookup.TimeoutError	the server was not reached or did not reply in time (since 6.6).

class Type#

Indicates the type of DNS lookup that was performed.

Constant

Description

QDnsLookup.A

IPv4 address records.

QDnsLookup.AAAA

IPv6 address records.

QDnsLookup.ANY

any records.

QDnsLookup.CNAME

canonical name records.

QDnsLookup.MX

mail exchange records.

QDnsLookup.NS

name server records.

QDnsLookup.PTR

pointer records.

QDnsLookup.SRV

service records.

QDnsLookup.TXT

text records.

Constant	Description
QDnsLookup.A	IPv4 address records.
QDnsLookup.AAAA	IPv6 address records.
QDnsLookup.ANY	any records.
QDnsLookup.CNAME	canonical name records.
QDnsLookup.MX	mail exchange records.
QDnsLookup.NS	name server records.
QDnsLookup.PTR	pointer records.
QDnsLookup.SRV	service records.
QDnsLookup.TXT	text records.

Note

Properties can be used directly when from __feature__ import true_property is used or via accessor functions otherwise.

property errorᅟ: QDnsLookup.Error#

This property holds the type of error that occurred if the DNS lookup failed, or NoError ..

Access functions:

error()
Signal finished()

property errorStringᅟ: str#

This property holds a human-readable description of the error if the DNS lookup failed..

Access functions:

errorString()
Signal finished()

property nameᅟ: str#

This property holds the name to lookup..

If the name to look up is empty, QDnsLookup will attempt to resolve the root domain of DNS. That query is usually performed with type set to NS .

Note

The name will be encoded using IDNA, which means it’s unsuitable for querying SRV records compatible with the DNS-SD specification.

Access functions:

name()
setName()
Signal nameChanged()

property nameserverᅟ: QHostAddress#

This property holds the nameserver to use for DNS lookup..

Access functions:

nameserver()
setNameserver()
Signal nameserverChanged()

property nameserverPortᅟ: int#

This property holds the port number of nameserver to use for DNS lookup..

Note

Setting the port number to any value other than the default (53) can cause the name resolution to fail, depending on the operating system limitations and firewalls. Notably, the Windows API used by QDnsLookup is unable to handle alternate port numbers.

Access functions:

nameserverPort()
setNameserverPort()
Signal nameserverPortChanged()

property typeᅟ: QDnsLookup.Type#

This property holds the type of DNS lookup..

Access functions:

type()
setType()
Signal typeChanged()

__init__(type, name, nameserver[, parent=None])#

Parameters:

type – Type
name – str
nameserver – QHostAddress
parent – QObject

Constructs a QDnsLookup object to issue a query for name of record type type, using the DNS server nameserver running on the default DNS port, and sets parent as the parent object.

__init__(type, name, nameserver, port[, parent=None])

Parameters:

type – Type
name – str
nameserver – QHostAddress
port – int
parent – QObject

Constructs a QDnsLookup object to issue a query for name of record type type, using the DNS server nameserver running on port port, and sets parent as the parent object.

Note

__init__([parent=None])

Parameters:: parent – QObject

Constructs a QDnsLookup object and sets parent as the parent object.

The type property will default to A .

__init__(type, name[, parent=None])

Parameters:

type – Type
name – str
parent – QObject

Constructs a QDnsLookup object for the given type and name and sets parent as the parent object.

abort()#

Aborts the DNS lookup operation.

If the lookup is already finished, does nothing.

canonicalNameRecords()#

Return type:: .list of QDnsDomainNameRecord

Returns the list of canonical name records associated with this lookup.

error()#

Return type:: Error

Getter of property errorᅟ .

errorString()#

Return type:: str

Getter of property errorStringᅟ .

finished()#

This signal is emitted when the reply has finished processing.

Notification signal of property errorᅟ .

hostAddressRecords()#

Return type:: .list of QDnsHostAddressRecord

Returns the list of host address records associated with this lookup.

isFinished()#

Return type:: bool

Returns whether the reply has finished or was aborted.

lookup()#

Performs the DNS lookup.

The finished() signal is emitted upon completion.

mailExchangeRecords()#

Return type:: .list of 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()#

Return type:: str

See also

setName()

Getter of property nameᅟ .

nameChanged(name)#

Parameters:: name – str

This signal is emitted when the lookup name changes. name is the new lookup name.

Notification signal of property nameᅟ .

nameServerRecords()#

Return type:: .list of QDnsDomainNameRecord

Returns the list of name server records associated with this lookup.

nameserver()#

Return type:: QHostAddress

See also

setNameserver()

Getter of property nameserverᅟ .

nameserverChanged(nameserver)#

Parameters:: nameserver – QHostAddress

Notification signal of property nameserverᅟ .

nameserverPort()#

Return type:: int

See also

setNameserverPort()

Getter of property nameserverPortᅟ .

nameserverPortChanged(port)#

Parameters:: port – int

Notification signal of property nameserverPortᅟ .

pointerRecords()#

Return type:: .list of QDnsDomainNameRecord

Returns the list of pointer records associated with this lookup.

serviceRecords()#

Return type:: .list of 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(name)#

Parameters:: name – str

See also

name()

Setter of property nameᅟ .

setNameserver(nameserver)#

Parameters:: nameserver – QHostAddress

See also

nameserver()

Setter of property nameserverᅟ .

setNameserver(nameserver, port)

Parameters:

nameserver – QHostAddress
port – int

Sets the nameserver to nameserver and the port to port.

Note

See also

nameserver nameserverPort

setNameserverPort(port)#

Parameters:: port – int

See also

nameserverPort()

Setter of property nameserverPortᅟ .

setType(arg__1)#

Parameters:: arg__1 – Type

See also

type()

Setter of property typeᅟ .

textRecords()#

Return type:: .list of QDnsTextRecord

Returns the list of text records associated with this lookup.

type()#

Return type:: Type

See also

setType()

Getter of property typeᅟ .

typeChanged(type)#

Parameters:: type – Type

This signal is emitted when the lookup type changes. type is the new lookup type.

Notification signal of property typeᅟ .