<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/src/network/qdns.cpp:1597 --> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>TQDns Class</title> <style type="text/css"><!-- fn { margin-left: 1cm; text-indent: -1cm; } a:link { color: #004faf; text-decoration: none } a:visited { color: #672967; text-decoration: none } body { background: #ffffff; color: black; } --></style> </head> <body> <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr bgcolor="#E5E5E5"> <td valign=center> <a href="index.html"> <font color="#004faf">Home</font></a> | <a href="classes.html"> <font color="#004faf">All Classes</font></a> | <a href="mainclasses.html"> <font color="#004faf">Main Classes</font></a> | <a href="annotated.html"> <font color="#004faf">Annotated</font></a> | <a href="groups.html"> <font color="#004faf">Grouped Classes</font></a> | <a href="functions.html"> <font color="#004faf">Functions</font></a> </td> <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="ntqobject.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="ntqvaluelist.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="ntqvaluelist.html">TQValueList</a><TQHostAddress> list = myDns.addresses(); TQValueList<TQHostAddress>::Iterator it = list.<a href="ntqvaluelist.html#begin">begin</a>(); while( it != list.<a href="ntqvaluelist.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="ntqvaluelist.html#begin">begin</a>(); while( it != list.<a href="ntqvaluelist.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="ntqvaluelist.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> Q_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="ntqvaluelist.html">TQValueList</a><TQDns::MailServer> list = myDns.mailServers(); TQValueList<TQDns::MailServer>::Iterator it = list.<a href="ntqvaluelist.html#begin">begin</a>(); while( it != list.<a href="ntqvaluelist.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="ntqvaluelist.html#begin">begin</a>(); while( it != list.<a href="ntqvaluelist.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="ntqvaluelist.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> Q_UINT16 TQDns::Server::priority <li> Q_UINT16 TQDns::Server::weight <li> Q_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="ntqvaluelist.html">TQValueList</a><TQDns::Server> list = myDns.servers(); TQValueList<TQDns::Server>::Iterator it = list.<a href="ntqvaluelist.html#begin">begin</a>(); while( it != list.<a href="ntqvaluelist.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="ntqvaluelist.html#begin">begin</a>(); while( it != list.<a href="ntqvaluelist.html#end">end</a>() ) { myProcessing( *it ); ++it; } </pre> <!-- eof --> <hr><p> This file is part of the <a href="index.html">TQt toolkit</a>. Copyright © 1995-2007 <a href="http://www.trolltech.com/">Trolltech</a>. 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