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Referencia de la Clase QDns

The QDns class provides asynchronous DNS lookups.networkBoth Windows and Unix provide synchronous DNS lookups; Windows provides some asynchronous support too. At the time of writing neither operating system provides asynchronous support for anything other than hostname-to-address mapping. Más...

#include <qdns.h>

Diagrama de herencias de QDns
QObject QObject Qt Qt Qt Qt QDnsUgleHack

Lista de todos los miembros.

Clases

class  MailServer
 The QDns::MailServer class is described in QDns::mailServers(). Más...
class  Server
 The QDns::Server class is described in QDns::servers(). Más...

Tipos públicos

enum  RecordType {
  None, A, Aaaa, Mx,
  Srv, Cname, Ptr, Txt,
  None, A, Aaaa, Mx,
  Srv, Cname, Ptr, Txt
}
enum  RecordType {
  None, A, Aaaa, Mx,
  Srv, Cname, Ptr, Txt,
  None, A, Aaaa, Mx,
  Srv, Cname, Ptr, Txt
}

Señales

void resultsReady ()
void resultsReady ()

Métodos públicos

 QDns ()
 QDns (const QString &label, RecordType rr=A)
 QDns (const QHostAddress &address, RecordType rr=Ptr)
virtual ~QDns ()
virtual void setLabel (const QString &label)
virtual void setLabel (const QHostAddress &address)
QString label () const
virtual void setRecordType (RecordType rr=A)
RecordType recordType () const
bool isWorking () const
QValueList< QHostAddressaddresses () const
QValueList< MailServermailServers () const
QValueList< Serverservers () const
QStringList hostNames () const
QStringList texts () const
QString canonicalName () const
QStringList qualifiedNames () const
 QDns ()
 QDns (const QString &label, RecordType rr=A)
 QDns (const QHostAddress &address, RecordType rr=Ptr)
virtual ~QDns ()
virtual void setLabel (const QString &label)
virtual void setLabel (const QHostAddress &address)
QString label () const
virtual void setRecordType (RecordType rr=A)
RecordType recordType () const
bool isWorking () const
QValueList< QHostAddressaddresses () const
QValueList< MailServermailServers () const
QValueList< Serverservers () const
QStringList hostNames () const
QStringList texts () const
QString canonicalName () const
QStringList qualifiedNames () const

Amigas

class QDnsAnswer
class QDnsManager

Descripción detallada

The QDns class provides asynchronous DNS lookups.

network

Both Windows and Unix provide synchronous DNS lookups; Windows provides some asynchronous support too. At the time of writing neither operating system provides asynchronous support for anything other than hostname-to-address mapping.

QDns rectifies this shortcoming, by providing asynchronous caching lookups for the record types that we expect modern GUI applications to need in the near future.

The class is not straightforward to use (although it is much simpler than the native APIs); QSocket provides much easier to use TCP connection facilities. The aim of QDns is to provide a correct and small API to the DNS and nothing more. (We use "correctness" to mean that the DNS information is correctly cached, and correctly timed out.)

The API comprises a constructor, functions to set the DNS node (the domain in DNS terminology) and record type (setLabel() and setRecordType()), the corresponding get functions, an isWorking() function to determine whether QDns is working or reading, a resultsReady() signal and query functions for the result.

There is one query function for each RecordType, namely addresses(), mailServers(), servers(), hostNames() and texts(). There are also two generic query functions: canonicalName() returns the name you'll presumably end up using (the exact meaning of this depends on the record type) and qualifiedNames() returns a list of the fully qualified names label() maps to.

Ver también:
QSocket

Documentación de las enumeraciones miembro de la clase

This enum type defines the record types QDns can handle. The DNS provides many more; these are the ones we've judged to be in current use, useful for GUI programs and important enough to support right away:

None No information. This exists only so that QDns can have a default.

A IPv4 addresses. By far the most common type.

Aaaa IPv6 addresses. So far mostly unused.

Mx Mail eXchanger names. Used for mail delivery.

Srv SeRVer names. Generic record type for finding servers. So far mostly unused.

Cname Canonical names. Maps from nicknames to the true name (the canonical name) for a host.

Ptr name PoinTeRs. Maps from IPv4 or IPv6 addresses to hostnames.

Txt arbitrary TeXT for domains.

We expect that some support for the RFC-2535 extensions will be added in future versions.

Valores de enumeraciones:
None 
A 
Aaaa 
Mx 
Srv 
Cname 
Ptr 
Txt 
None 
A 
Aaaa 
Mx 
Srv 
Cname 
Ptr 
Txt 
Valores de enumeraciones:
None 
A 
Aaaa 
Mx 
Srv 
Cname 
Ptr 
Txt 
None 
A 
Aaaa 
Mx 
Srv 
Cname 
Ptr 
Txt 

Documentación del constructor y destructor

QDns::QDns ( )

Constructs a DNS query object with invalid settings for both the label and the search type.

QDns::QDns ( const QString label,
RecordType  rr = A 
)

Constructs a DNS query object that will return record type rr information about label.

The DNS lookup is started the next time the application enters the event loop. When the result is found the signal resultsReady() is emitted.

rr defaults to A, IPv4 addresses.

QDns::QDns ( const QHostAddress address,
RecordType  rr = Ptr 
)

Constructs a DNS query object that will return record type rr information about host address address. The label is set to the IN-ADDR.ARPA domain name. This is useful in combination with the Ptr record type (e.g. if you want to look up a hostname for a given address).

The DNS lookup is started the next time the application enters the event loop. When the result is found the signal resultsReady() is emitted.

rr defaults to Ptr, that maps addresses to hostnames.

QDns::~QDns ( ) [virtual]

Destroys the DNS query object and frees its allocated resources.

QDns::QDns ( )
QDns::QDns ( const QString label,
RecordType  rr = A 
)
QDns::QDns ( const QHostAddress address,
RecordType  rr = Ptr 
)
virtual QDns::~QDns ( ) [virtual]

Documentación de las funciones miembro

QValueList< QHostAddress > QDns::addresses ( ) const

Returns a list of the addresses for this name if this QDns object has a recordType() of QDns::A or QDns::Aaaa and the answer is available; otherwise returns an empty list.

As a special case, if label() is a valid numeric IP address, this function returns that address.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QValueList<QHostAddress> list = myDns.addresses();
    QValueList<QHostAddress>::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }
QValueList<QHostAddress> QDns::addresses ( ) const
QString QDns::canonicalName ( ) const

Returns the canonical name for this DNS node. (This works regardless of what recordType() is set to.)

If the canonical name isn't known, this function returns a null string.

The canonical name of a DNS node is its full name, or the full name of the target of its CNAME. For example, if l.trolltech.com is a CNAME to lillian.troll.no, and the search path for QDns is "trolltech.com", then the canonical name for all of "lillian", "l", "lillian.troll.no." and "l.trolltech.com" is "lillian.troll.no.".

QString QDns::canonicalName ( ) const
QStringList QDns::hostNames ( ) const

Returns a list of host names if the record type is Ptr.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QStringList list = myDns.hostNames();
    QStringList::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }
QStringList QDns::hostNames ( ) const
bool QDns::isWorking ( ) const
bool QDns::isWorking ( ) const

Returns TRUE if QDns is doing a lookup for this object (i.e. if it does not already have the necessary information); otherwise returns FALSE.

QDns emits the resultsReady() signal when the status changes to FALSE.

QString QDns::label ( ) const [inline]
QString QDns::label ( ) const [inline]

Returns the domain name for which this object returns information.

Ver también:
setLabel()
QValueList< QDns::MailServer > QDns::mailServers ( ) const

Returns a list of mail servers if the record type is Mx. The class QDns::MailServer contains the following public variables: QString QDns::MailServer::name Q_UINT16 QDns::MailServer::priority

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QValueList<QDns::MailServer> list = myDns.mailServers();
    QValueList<QDns::MailServer>::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }
QValueList<MailServer> QDns::mailServers ( ) const
QStringList QDns::qualifiedNames ( ) const [inline]

Returns a list of the fully qualified names label() maps to.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QStringList list = myDns.qualifiedNames();
    QStringList::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }
QStringList QDns::qualifiedNames ( ) const [inline]
QDns::RecordType QDns::recordType ( ) const [inline]

Returns the record type of this DNS query object.

Ver también:
setRecordType() RecordType
RecordType QDns::recordType ( ) const [inline]
void QDns::resultsReady ( ) [signal]
void QDns::resultsReady ( ) [signal]

This signal is emitted when results are available for one of the qualifiedNames().

QValueList<Server> QDns::servers ( ) const
QValueList< QDns::Server > QDns::servers ( ) const

Returns a list of servers if the record type is Srv. The class QDns::Server contains the following public variables: QString QDns::Server::name Q_UINT16 QDns::Server::priority Q_UINT16 QDns::Server::weight Q_UINT16 QDns::Server::port

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QValueList<QDns::Server> list = myDns.servers();
    QValueList<QDns::Server>::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }
void QDns::setLabel ( const QHostAddress address) [virtual]

Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Sets this DNS query object to query for information about the host address address. The label is set to the IN-ADDR.ARPA domain name. This is useful in combination with the Ptr record type (e.g. if you want to look up a hostname for a given address).

void QDns::setLabel ( const QString label) [virtual]

Sets this DNS query object to query for information about label.

This does not change the recordType(), but its isWorking() status will probably change as a result.

The DNS lookup is started the next time the application enters the event loop. When the result is found the signal resultsReady() is emitted.

virtual void QDns::setLabel ( const QString label) [virtual]
virtual void QDns::setLabel ( const QHostAddress address) [virtual]
virtual void QDns::setRecordType ( RecordType  rr = A) [virtual]
void QDns::setRecordType ( RecordType  rr = A) [virtual]

Sets this object to query for record type rr records.

The DNS lookup is started the next time the application enters the event loop. When the result is found the signal resultsReady() is emitted.

Ver también:
RecordType
QStringList QDns::texts ( ) const

Returns a list of texts if the record type is Txt.

Note that if you want to iterate over the list, you should iterate over a copy, e.g.

    QStringList list = myDns.texts();
    QStringList::Iterator it = list.begin();
    while( it != list.end() ) {
        myProcessing( *it );
        ++it;
    }
QStringList QDns::texts ( ) const

Documentación de las funciones relacionadas y clases amigas

QDnsAnswer [friend]
QDnsManager [friend]

La documentación para esta clase fue generada a partir de los siguientes ficheros:
 Todo Clases Namespaces Archivos Funciones Variables 'typedefs' Enumeraciones Valores de enumeraciones Propiedades Amigas 'defines'