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< td align = "right" valign = "center" > < img src = "logo32.png" align = "right" width = "64" height = "32" border = "0" > < / td > < / tr > < / table > < h1 align = center > TQDns Class Reference< br > < small > [< a href = "network.html" > network module< / a > ]< / small > < / h1 >
< p > The TQDns class provides asynchronous DNS lookups.
< a href = "#details" > More...< / a >
< p > < tt > #include < < a href = "qdns-h.html" > ntqdns.h< / a > > < / tt >
< p > Inherits < a href = "tqobject.html" > TQObject< / a > .
< p > < a href = "qdns-members.html" > List of all member functions.< / a >
< h2 > Public Members< / h2 >
< ul >
< li class = fn > enum < a href = "#RecordType-enum" > < b > RecordType< / b > < / a > { None, A, Aaaa, Mx, Srv, Cname, Ptr, Txt }< / li >
< li class = fn > < a href = "#TQDns" > < b > TQDns< / b > < / a > ()< / li >
< li class = fn > < a href = "#TQDns-2" > < b > TQDns< / b > < / a > ( const TQString & label, RecordType rr = A )< / li >
< li class = fn > < a href = "#TQDns-3" > < b > TQDns< / b > < / a > ( const TQHostAddress & address, RecordType rr = Ptr )< / li >
< li class = fn > virtual < a href = "#~TQDns" > < b > ~TQDns< / b > < / a > ()< / li >
< li class = fn > virtual void < a href = "#setLabel" > < b > setLabel< / b > < / a > ( const TQString & label )< / li >
< li class = fn > virtual void < a href = "#setLabel-2" > < b > setLabel< / b > < / a > ( const TQHostAddress & address )< / li >
< li class = fn > TQString < a href = "#label" > < b > label< / b > < / a > () const< / li >
< li class = fn > virtual void < a href = "#setRecordType" > < b > setRecordType< / b > < / a > ( RecordType rr = A )< / li >
< li class = fn > RecordType < a href = "#recordType" > < b > recordType< / b > < / a > () const< / li >
< li class = fn > bool < a href = "#isWorking" > < b > isWorking< / b > < / a > () const< / li >
< li class = fn > TQValueList< TQHostAddress> < a href = "#addresses" > < b > addresses< / b > < / a > () const< / li >
< li class = fn > TQValueList< MailServer> < a href = "#mailServers" > < b > mailServers< / b > < / a > () const< / li >
< li class = fn > TQValueList< Server> < a href = "#servers" > < b > servers< / b > < / a > () const< / li >
< li class = fn > TQStringList < a href = "#hostNames" > < b > hostNames< / b > < / a > () const< / li >
< li class = fn > TQStringList < a href = "#texts" > < b > texts< / b > < / a > () const< / li >
< li class = fn > TQString < a href = "#canonicalName" > < b > canonicalName< / b > < / a > () const< / li >
< li class = fn > TQStringList < a href = "#qualifiedNames" > < b > qualifiedNames< / b > < / a > () const< / li >
< / ul >
< h2 > Signals< / h2 >
< ul >
< li class = fn > void < a href = "#resultsReady" > < b > resultsReady< / b > < / a > ()< / li >
< / ul >
< hr > < a name = "details" > < / a > < h2 > Detailed Description< / h2 >
The TQDns class provides asynchronous DNS lookups.
< p >
< p > 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.
< p > TQDns rectifies this shortcoming, by providing asynchronous caching
lookups for the record types that we expect modern GUI
applications to need in the near future.
< p > The class is < em > not< / em > straightforward to use (although it is much
simpler than the native APIs); < a href = "ntqsocket.html" > TQSocket< / a > provides much easier to use
TCP connection facilities. The aim of TQDns 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.)
< p > The API comprises a constructor, functions to set the DNS node
(the domain in DNS terminology) and record type (< a href = "#setLabel" > setLabel< / a > () and
< a href = "#setRecordType" > setRecordType< / a > ()), the corresponding get functions, an < a href = "#isWorking" > isWorking< / a > ()
function to determine whether TQDns is working or reading, a
< a href = "#resultsReady" > resultsReady< / a > () signal and query functions for the result.
< p > There is one query function for each RecordType, namely
< a href = "#addresses" > addresses< / a > (), < a href = "#mailServers" > mailServers< / a > (), < a href = "#servers" > servers< / a > (), < a href = "#hostNames" > hostNames< / a > () and < a href = "#texts" > texts< / a > ().
There are also two generic query functions: < a href = "#canonicalName" > canonicalName< / a > ()
returns the name you'll presumably end up using (the exact meaning
of this depends on the record type) and < a href = "#qualifiedNames" > qualifiedNames< / a > () returns a
list of the fully qualified names < a href = "#label" > label< / a > () maps to.
< p > < p > See also < a href = "ntqsocket.html" > TQSocket< / a > and < a href = "io.html" > Input/Output and Networking< / a > .
< hr > < h2 > Member Type Documentation< / h2 >
< h3 class = fn > < a name = "RecordType-enum" > < / a > TQDns::RecordType< / h3 >
< p > This enum type defines the record types TQDns 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:
< ul >
< li > < tt > TQDns::None< / tt > - No information. This exists only so that TQDns can
have a default.
< li > < tt > TQDns::A< / tt > - IPv4 addresses. By far the most common type.
< li > < tt > TQDns::Aaaa< / tt > - IPv6 addresses. So far mostly unused.
< li > < tt > TQDns::Mx< / tt > - Mail eXchanger names. Used for mail delivery.
< li > < tt > TQDns::Srv< / tt > - SeRVer names. Generic record type for finding
servers. So far mostly unused.
< li > < tt > TQDns::Cname< / tt > - Canonical names. Maps from nicknames to the true
name (the canonical name) for a host.
< li > < tt > TQDns::Ptr< / tt > - name PoinTeRs. Maps from IPv4 or IPv6 addresses to hostnames.
< li > < tt > TQDns::Txt< / tt > - arbitrary TeXT for domains.
< / ul > < p > We expect that some support for the
< a href = "http://www.dns.net/dnsrd/rfc/rfc2535.html" > RFC-2535< / a >
extensions will be added in future versions.
< hr > < h2 > Member Function Documentation< / h2 >
< h3 class = fn > < a name = "TQDns" > < / a > TQDns::TQDns ()
< / h3 >
Constructs a DNS query object with invalid settings for both the
label and the search type.
< h3 class = fn > < a name = "TQDns-2" > < / a > TQDns::TQDns ( const < a href = "ntqstring.html" > TQString< / a > & label, < a href = "ntqdns.html#RecordType-enum" > RecordType< / a > rr = A )
< / h3 >
Constructs a DNS query object that will return record type < em > rr< / em >
information about < em > label< / em > .
< p > The DNS lookup is started the next time the application enters the
event loop. When the result is found the signal < a href = "#resultsReady" > resultsReady< / a > () is
emitted.
< p > < em > rr< / em > defaults to < a href = "#RecordType-enum" > A< / a > , IPv4 addresses.
< h3 class = fn > < a name = "TQDns-3" > < / a > TQDns::TQDns ( const < a href = "ntqhostaddress.html" > TQHostAddress< / a > & address, < a href = "ntqdns.html#RecordType-enum" > RecordType< / a > rr = Ptr )
< / h3 >
Constructs a DNS query object that will return record type < em > rr< / em >
information about host address < em > address< / em > . The label is set to the
IN-ADDR.ARPA domain name. This is useful in combination with the
< a href = "#RecordType-enum" > Ptr< / a > record type (e.g. if you want to look up a hostname for a
given address).
< p > The DNS lookup is started the next time the application enters the
event loop. When the result is found the signal < a href = "#resultsReady" > resultsReady< / a > () is
emitted.
< p > < em > rr< / em > defaults to < a href = "#RecordType-enum" > Ptr< / a > , that maps addresses to hostnames.
< h3 class = fn > < a name = "~TQDns" > < / a > TQDns::~TQDns ()< tt > [virtual]< / tt >
< / h3 >
Destroys the DNS query object and frees its allocated resources.
< h3 class = fn > < a href = "tqvaluelist.html" > TQValueList< / a > < TQHostAddress> < a name = "addresses" > < / a > TQDns::addresses () const
< / h3 >
Returns a list of the addresses for this name if this TQDns object
has a < a href = "#recordType" > recordType< / a > () of < a href = "#RecordType-enum" > TQDns::A< / a > or < a href = "#RecordType-enum" > TQDns::Aaaa< / a > and the answer
is available; otherwise returns an empty list.
< p > As a special case, if < a href = "#label" > label< / a > () is a valid numeric IP address, this
function returns that address.
< p > Note that if you want to iterate over the list, you should iterate
over a copy, e.g.
< pre >
< a href = "tqvaluelist.html" > TQValueList< / a > < TQHostAddress> list = myDns.addresses();
TQValueList< TQHostAddress> ::Iterator it = list.< a href = "tqvaluelist.html#begin" > begin< / a > ();
while( it != list.< a href = "tqvaluelist.html#end" > end< / a > () ) {
myProcessing( *it );
++it;
}
< / pre >
< p >
< h3 class = fn > < a href = "ntqstring.html" > TQString< / a > < a name = "canonicalName" > < / a > TQDns::canonicalName () const
< / h3 >
Returns the canonical name for this DNS node. (This works
regardless of what < a href = "#recordType" > recordType< / a > () is set to.)
< p > If the canonical name isn't known, this function returns a null
string.
< p > 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 TQDns is
"trolltech.com", then the canonical name for all of "lillian",
"l", "lillian.troll.no." and "l.trolltech.com" is
"lillian.troll.no.".
< h3 class = fn > < a href = "ntqstringlist.html" > TQStringList< / a > < a name = "hostNames" > < / a > TQDns::hostNames () const
< / h3 >
Returns a list of host names if the record type is < a href = "#RecordType-enum" > Ptr< / a > .
< p > Note that if you want to iterate over the list, you should iterate
over a copy, e.g.
< pre >
< a href = "ntqstringlist.html" > TQStringList< / a > list = myDns.hostNames();
TQStringList::Iterator it = list.< a href = "tqvaluelist.html#begin" > begin< / a > ();
while( it != list.< a href = "tqvaluelist.html#end" > end< / a > () ) {
myProcessing( *it );
++it;
}
< / pre >
< p >
< h3 class = fn > bool < a name = "isWorking" > < / a > TQDns::isWorking () const
< / h3 >
Returns TRUE if TQDns is doing a lookup for this object (i.e. if it
does not already have the necessary information); otherwise
returns FALSE.
< p > TQDns emits the < a href = "#resultsReady" > resultsReady< / a > () signal when the status changes to FALSE.
< p > Example: < a href = "mail-example.html#x705" > network/mail/smtp.cpp< / a > .
< h3 class = fn > < a href = "ntqstring.html" > TQString< / a > < a name = "label" > < / a > TQDns::label () const
< / h3 >
< p > Returns the domain name for which this object returns information.
< p > < p > See also < a href = "#setLabel" > setLabel< / a > ().
< h3 class = fn > < a href = "tqvaluelist.html" > TQValueList< / a > < MailServer> < a name = "mailServers" > < / a > TQDns::mailServers () const
< / h3 >
Returns a list of mail servers if the record type is < a href = "#RecordType-enum" > Mx< / a > . The
class < tt > TQDns::MailServer< / tt > contains the following public variables:
< ul >
< li > < a href = "ntqstring.html" > TQString< / a > TQDns::MailServer::name
< li > TQ_UINT16 TQDns::MailServer::priority
< / ul >
< p > Note that if you want to iterate over the list, you should iterate
over a copy, e.g.
< pre >
< a href = "tqvaluelist.html" > TQValueList< / a > < TQDns::MailServer> list = myDns.mailServers();
TQValueList< TQDns::MailServer> ::Iterator it = list.< a href = "tqvaluelist.html#begin" > begin< / a > ();
while( it != list.< a href = "tqvaluelist.html#end" > end< / a > () ) {
myProcessing( *it );
++it;
}
< / pre >
< p >
< p > Example: < a href = "mail-example.html#x706" > network/mail/smtp.cpp< / a > .
< h3 class = fn > < a href = "ntqstringlist.html" > TQStringList< / a > < a name = "qualifiedNames" > < / a > TQDns::qualifiedNames () const
< / h3 >
< p > Returns a list of the fully qualified names < a href = "#label" > label< / a > () maps to.
< p > Note that if you want to iterate over the list, you should iterate
over a copy, e.g.
< pre >
< a href = "ntqstringlist.html" > TQStringList< / a > list = myDns.qualifiedNames();
TQStringList::Iterator it = list.< a href = "tqvaluelist.html#begin" > begin< / a > ();
while( it != list.< a href = "tqvaluelist.html#end" > end< / a > () ) {
myProcessing( *it );
++it;
}
< / pre >
< p >
< h3 class = fn > < a href = "ntqdns.html#RecordType-enum" > RecordType< / a > < a name = "recordType" > < / a > TQDns::recordType () const
< / h3 >
< p > Returns the record type of this DNS query object.
< p > < p > See also < a href = "#setRecordType" > setRecordType< / a > () and < a href = "#RecordType-enum" > RecordType< / a > .
< h3 class = fn > void < a name = "resultsReady" > < / a > TQDns::resultsReady ()< tt > [signal]< / tt >
< / h3 >
< p > This signal is emitted when results are available for one of the
< a href = "#qualifiedNames" > qualifiedNames< / a > ().
< p > Example: < a href = "mail-example.html#x707" > network/mail/smtp.cpp< / a > .
< h3 class = fn > < a href = "tqvaluelist.html" > TQValueList< / a > < Server> < a name = "servers" > < / a > TQDns::servers () const
< / h3 >
Returns a list of servers if the record type is < a href = "#RecordType-enum" > Srv< / a > . The class
< tt > TQDns::Server< / tt > contains the following public variables:
< ul >
< li > < a href = "ntqstring.html" > TQString< / a > TQDns::Server::name
< li > TQ_UINT16 TQDns::Server::priority
< li > TQ_UINT16 TQDns::Server::weight
< li > TQ_UINT16 TQDns::Server::port
< / ul >
< p > Note that if you want to iterate over the list, you should iterate
over a copy, e.g.
< pre >
< a href = "tqvaluelist.html" > TQValueList< / a > < TQDns::Server> list = myDns.servers();
TQValueList< TQDns::Server> ::Iterator it = list.< a href = "tqvaluelist.html#begin" > begin< / a > ();
while( it != list.< a href = "tqvaluelist.html#end" > end< / a > () ) {
myProcessing( *it );
++it;
}
< / pre >
< h3 class = fn > void < a name = "setLabel" > < / a > TQDns::setLabel ( const < a href = "ntqstring.html" > TQString< / a > & label )< tt > [virtual]< / tt >
< / h3 >
Sets this DNS query object to query for information about < em > label< / em > .
< p > This does not change the < a href = "#recordType" > recordType< / a > (), but its < a href = "#isWorking" > isWorking< / a > () status
will probably change as a result.
< p > The DNS lookup is started the next time the application enters the
event loop. When the result is found the signal < a href = "#resultsReady" > resultsReady< / a > () is
emitted.
< h3 class = fn > void < a name = "setLabel-2" > < / a > TQDns::setLabel ( const < a href = "ntqhostaddress.html" > TQHostAddress< / a > & address )< tt > [virtual]< / tt >
< / h3 >
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
< p > Sets this DNS query object to query for information about the host
address < em > address< / em > . The label is set to the IN-ADDR.ARPA domain
name. This is useful in combination with the < a href = "#RecordType-enum" > Ptr< / a > record type
(e.g. if you want to look up a hostname for a given address).
< h3 class = fn > void < a name = "setRecordType" > < / a > TQDns::setRecordType ( < a href = "ntqdns.html#RecordType-enum" > RecordType< / a > rr = A )< tt > [virtual]< / tt >
< / h3 >
Sets this object to query for record type < em > rr< / em > records.
< p > The DNS lookup is started the next time the application enters the
event loop. When the result is found the signal < a href = "#resultsReady" > resultsReady< / a > () is
emitted.
< p > < p > See also < a href = "#RecordType-enum" > RecordType< / a > .
< h3 class = fn > < a href = "ntqstringlist.html" > TQStringList< / a > < a name = "texts" > < / a > TQDns::texts () const
< / h3 >
Returns a list of texts if the record type is < a href = "#RecordType-enum" > Txt< / a > .
< p > Note that if you want to iterate over the list, you should iterate
over a copy, e.g.
< pre >
< a href = "ntqstringlist.html" > TQStringList< / a > list = myDns.texts();
TQStringList::Iterator it = list.< a href = "tqvaluelist.html#begin" > begin< / a > ();
while( it != list.< a href = "tqvaluelist.html#end" > end< / a > () ) {
myProcessing( *it );
++it;
}
< / pre >
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< a href = "troll.html" > Trolltech< / a > < td align = center > < a href = "trademarks.html" > Trademarks< / a >
< td align = right > < div align = right > TQt 3.3.8< / div >
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