KNetwork::KResolver Class Reference

#include <kresolver.h>

Inherits TQObject.

Public Types
enum	SocketFamilies {   UnknownFamily = 0x0001 , UnixFamily = 0x0002 , LocalFamily = UnixFamily , IPv4Family = 0x0004 ,   IPv6Family = 0x0008 , InternetFamily = IPv4Family | IPv6Family , InetFamily = InternetFamily , KnownFamily = ~UnknownFamily ,   AnyFamily = KnownFamily | UnknownFamily }
enum	Flags {   Passive = 0x01 , CanonName = 0x02 , NoResolve = 0x04 , NoSrv = 0x08 ,   Multiport = 0x10 , UseSrv = 0x20 }
enum	ErrorCodes {   NoError = 0 , AddrFamily = -1 , TryAgain = -2 , NonRecoverable = -3 ,   BadFlags = -4 , Memory = -5 , NoName = -6 , UnsupportedFamily = -7 ,   UnsupportedService = -8 , UnsupportedSocketType = -9 , UnknownError = -10 , SystemError = -11 ,   Canceled = -100 }
enum	StatusCodes {   Idle = 0 , Queued = 1 , InProgress = 5 , PostProcessing = 6 ,   Success = 10 , Failed = -101 }

Signals
void	finished (KResolverResults results)

Public Member Functions
	KResolver (TQObject *=0L, const char *=0L)
	KResolver (const TQString &nodename, const TQString &servicename=TQString::null, TQObject *=0L, const char *=0L)
virtual	~KResolver ()
int	status () const
int	error () const
int	systemError () const
TQString	errorString () const
bool	isRunning () const
TQString	nodeName () const
TQString	serviceName () const
void	setNodeName (const TQString &nodename)
void	setServiceName (const TQString &service)
void	setAddress (const TQString &node, const TQString &service)
int	flags () const
int	setFlags (int flags)
void	setFamily (int families)
void	setSocketType (int type)
void	setProtocol (int protonum, const char *name=0L)
bool	start ()
bool	wait (int msec=0)
void	cancel (bool emitSignal=true)
KResolverResults	results () const
virtual bool	event (TQEvent *)

Static Public Member Functions
static TQString	errorString (int errorcode, int syserror=0)
static KResolverResults	resolve (const TQString &host, const TQString &service, int flags=0, int families=KResolver::InternetFamily)
static bool	resolveAsync (TQObject *userObj, const char *userSlot, const TQString &host, const TQString &service, int flags=0, int families=KResolver::InternetFamily)
static TQCString	domainToAscii (const TQString &unicodeDomain)
static TQString	domainToUnicode (const TQCString &asciiDomain)
static TQString	domainToUnicode (const TQString &asciiDomain)
static TQString	normalizeDomain (const TQString &domain)
static TQStrList	protocolName (int protonum)
static TQStrList	protocolName (const char *protoname)
static int	protocolNumber (const char *protoname)
static int	servicePort (const char *servname, const char *protoname)
static TQStrList	serviceName (const char *servname, const char *protoname)
static TQStrList	serviceName (int port, const char *protoname)
static TQString	localHostName ()

Protected Member Functions
void	setError (int errorcode, int systemerror=0)
virtual void	virtual_hook (int id, void *data)

Friends
class	KResolverResults
class	::KNetwork::Internal::KResolverManager

Detailed Description

Name and service resolution class.

This class provides support for doing name-to-binary resolution for nodenames and service ports. You should use this class if you need specific resolution techniques when creating a socket or if you want to inspect the results before calling the socket functions.

You can either create an object and set the options you want in it or you can simply call the static member functions, which will create standard Resolver objects and dispatch the resolution for you. Normally, the static functions will be used, except in cases where specific options must be set.

A Resolver object defaults to the following:

• address family: any address family
• socket type: streaming socket
• protocol: implementation-defined. Generally, TCP
• host and service: unset

Author

Thiago Macieira thiag.nosp@m.o.ma.nosp@m.cieir.nosp@m.a@kd.nosp@m.email.nosp@m..net

Definition at line 295 of file kresolver.h.

Member Enumeration Documentation

ErrorCodes

enum KNetwork::KResolver::ErrorCodes

Error codes.

These are the possible error values that objects of this class may return. See errorString() for getting a string representation for these errors.

• AddrFamily: Address family for the given nodename is not supported.
• TryAgain: Temporary failure in name resolution. You should try again.
• NonRecoverable: Non-recoverable failure in name resolution.
• BadFlags: Invalid flags were given.
• Memory: Memory allocation failure.
• NoName: The specified name or service doesn't exist.
• UnsupportedFamily: The requested socket family is not supported.
• UnsupportedService: The requested service is not supported for this socket type (i.e., a datagram service in a streaming socket).
• UnsupportedSocketType: The requested socket type is not supported.
• UnknownError: An unknown, unexpected error occurred.
• SystemError: A system error occurred. See systemError.
• Canceled: This request was cancelled by the user.

Definition at line 383 of file kresolver.h.

Flags

enum KNetwork::KResolver::Flags

Flags for the resolution.

These flags are used for setting the resolution behaviour for this object:

• Passive: resolve to a passive socket (i.e., one that can be used for binding to a local interface)
• CanonName: request that the canonical name for the given nodename be found and recorded
• NoResolve: request that no external resolution be performed. The given nodename and servicename will be resolved locally only.
• NoSrv: don't try to use SRV-based name-resolution. (deprecated)
• UseSrv: use SRV-based name resolution.
• Multiport: the port/service argument is a list of port numbers and ranges. (future extension)

Note

SRV-based lookup and Multiport are not implemented yet.

Definition at line 352 of file kresolver.h.

SocketFamilies

enum KNetwork::KResolver::SocketFamilies

Address family selection types.

These values can be OR-ed together to form a composite family selection.

• UnknownFamily: a family that is unknown to the current implementation
• KnownFamily: a family that is known to the implementation (the exact opposite of UnknownFamily)
• AnyFamilies: any address family is acceptable
• InternetFamily: an address for connecting to the Internet
• InetFamily: alias for InternetFamily
• IPv6Family: an IPv6 address only
• IPv4Family: an IPv4 address only
• UnixFamily: an address for the local Unix namespace (i.e., Unix sockets)
• LocalFamily: alias for UnixFamily

Definition at line 318 of file kresolver.h.

StatusCodes

enum KNetwork::KResolver::StatusCodes

Status codes.

These are the possible status for a Resolver object. A value greater than zero indicates normal behaviour, while negative values either indicate failure or error.

• Idle: resolution has not yet been started.
• Queued: resolution is queued but not yet in progress.
• InProgress: resolution is in progress.
• PostProcessing: resolution is in progress.
• Success: resolution is done; you can retrieve the results.
• Canceled: request cancelled by the user.
• Failed: resolution is done, but failed.

Note: the status Canceled and the error code Canceled are the same.

Note 2: the status Queued and InProgress might not be distinguishable. Some implementations might not differentiate one from the other.

Definition at line 421 of file kresolver.h.

Constructor & Destructor Documentation

KResolver() [1/2]

KResolver::KResolver	(	TQObject *	parent = 0L,
		const char *	name = 0L
	)

Default constructor.

Creates an empty Resolver object. You should set the wanted names and flags using the member functions before starting the name resolution.

Definition at line 296 of file kresolver.cpp.

KResolver() [2/2]

KResolver::KResolver	(	const TQString &	nodename,
		const TQString &	servicename = TQString::null,
		TQObject *	parent = 0L,
		const char *	name = 0L
	)

Constructor with host and service names.

Creates a Resolver object with the given host and service names. Flags are initialised to 0 and any address family will be accepted.

Parameters

nodename	The host name we want resolved.
servicename	The service name associated, like "http".

Definition at line 302 of file kresolver.cpp.

~KResolver()

KResolver::~KResolver ( )

virtual

Destructor.

When this object is deleted, it'll destroy all associated resources. If the resolution is still in progress, it will be cancelled and the signal will not be emitted.

Definition at line 309 of file kresolver.cpp.

Member Function Documentation

cancel()

void KResolver::cancel

(

bool

emitSignal = true

)

Cancels a running request.

This function will cancel a running request. If the request is not currently running or queued, this function does nothing.

Note: if you tell the signal to be emitted, be aware that it might or might not be emitted before this function returns.

Parameters

emitSignal

whether to emit the finished signal or not

Definition at line 512 of file kresolver.cpp.

domainToAscii()

TQCString KResolver::domainToAscii ( const TQString &  unicodeDomain )

static

Returns the domain name in an ASCII Compatible Encoding form, suitable for DNS lookups.

This is the base for International Domain Name support over the Internet.

Note this function may fail, in which case it'll return a null TQCString. Reasons for failure include use of unknown code points (Unicode characters).

Note that the encoding is illegible and, thus, should not be presented to the user, except if requested.

Parameters

unicodeDomain

the domain name to be encoded

Returns

the ACE-encoded suitable for DNS queries if successful, a null TQCString if failure.

Definition at line 1035 of file kresolver.cpp.

domainToUnicode() [1/2]

TQString KResolver::domainToUnicode ( const TQCString &  asciiDomain )

static

Does the inverse of domainToAscii and return an Unicode domain name from the given ACE-encoded domain.

This function may fail if the given domain cannot be successfully converted back to Unicode. Reasons for failure include a malformed domain name or good ones whose reencoding back to ACE don't match the form given here (e.g., ACE-encoding of an already ASCII-compatible domain).

It is, however, guaranteed that domains returned by domainToAscii will work.

Parameters

asciiDomain

the ACE-encoded domain name to be decoded

Returns

the Unicode representation of the given domain name if successful, the original string if not

Note

ACE = ASCII-Compatible Encoding, i.e., 7-bit

Definition at line 1073 of file kresolver.cpp.

domainToUnicode() [2/2]

TQString KResolver::domainToUnicode ( const TQString &  asciiDomain )

static

The same as above, but taking a TQString argument.

Parameters

asciiDomain

the ACE-encoded domain name to be decoded

Returns

the Unicode representation of the given domain name if successful, TQString::null if not.

Definition at line 1079 of file kresolver.cpp.

error()

int KResolver::error

(

)

const

Retrieve the error code in this object.

This function will return NoError if we are not in an error condition. See status and StatusCodes to find out what the current status is.

See also

errorString for getting a textual representation of this error

Definition at line 322 of file kresolver.cpp.

errorString() [1/2]

TQString KNetwork::KResolver::errorString ( ) const

inline

Returns the textual representation of the error in this object.

Definition at line 494 of file kresolver.h.

errorString() [2/2]

TQString KResolver::errorString ( int  errorcode, int  syserror = 0  )

static

Returns the string representation of this error code.

Parameters

errorcode	the error code. See ErrorCodes.
syserror	the system error code associated.

Returns

the string representation. This is already i18n'ed.

Definition at line 556 of file kresolver.cpp.

event()

bool KResolver::event ( TQEvent *  e )

virtual

Handles events.

Reimplemented from TQObject.

This function handles the events generated by the manager indicating that this object has finished processing.

Do not post events to this object.

Definition at line 532 of file kresolver.cpp.

finished

void KNetwork::KResolver::finished ( KResolverResults  results )

signal

This signal is emitted whenever the resolution is finished, one way or another (success or failure).

The results parameter will contain the resolved data.

Note: if you are doing multiple resolutions, you can use the TQObject::sender() function to distinguish one Resolver object from another.

Parameters

results

the resolved data; might be empty if the resolution failed

See also

results for information on what the results are

Note

This signal is always delivered in the GUI event thread, even for resolutions that were started in secondary threads.

flags()

int KResolver::flags

(

)

const

Retrieves the flags set for the resolution.

See also

Flags for an explanation on what flags are possible

Definition at line 383 of file kresolver.cpp.

isRunning()

bool KResolver::isRunning

(

)

const

Returns true if this object is currently running.

Definition at line 334 of file kresolver.cpp.

localHostName()

TQString KResolver::localHostName ( )

static

Returns this machine's local hostname.

Returns

this machine's local hostname

Since

3.5

Definition at line 969 of file kresolver.cpp.

nodeName()

TQString KResolver::nodeName

(

)

const

The nodename to which the resolution was/is to be performed.

Definition at line 340 of file kresolver.cpp.

normalizeDomain()

TQString KResolver::normalizeDomain ( const TQString &  domain )

static

Normalise a domain name.

In order to prevent simple mistakes in International Domain Names (IDN), it has been decided that certain code points (characters in Unicode) would be instead converted to others. This includes turning them all to lower case, as well certain other specific operations, as specified in the documents.

For instance, the German 'ß' will be changed into 'ss', while the micro symbol 'µ' will be changed to the Greek mu 'μ'.

Two equivalent domains have the same normalised form. And the normalised form of a normalised domain is itself (i.e., if d is normalised, the following is true: d == normalizeDomain(d) )

This operation is equivalent to encoding and the decoding a Unicode hostname.

Parameters

domain

a domain to be normalised

Returns

the normalised domain, or TQString::null if the domain is invalid.

Definition at line 1119 of file kresolver.cpp.

protocolName() [1/2]

TQStrList KResolver::protocolName ( const char *  protoname )

static

Finds all aliases for a given protocol name.

Parameters

protoname

the protocol name to be looked for

Returns

all the protocol names in a list. The first is the "proper" name.

Definition at line 675 of file kresolver.cpp.

protocolName() [2/2]

TQStrList KResolver::protocolName ( int  protonum )

static

Resolves a protocol number to its names.

Note: the returned TQStrList operates on deep-copies.

Parameters

protonum

the protocol number to be looked for

Returns

all the protocol names in a list. The first is the "proper" name.

Definition at line 614 of file kresolver.cpp.

protocolNumber()

int KResolver::protocolNumber ( const char *  protoname )

static

Resolves a protocol name to its number.

Parameters

protoname

the protocol name to be looked for

Returns

the protocol number or -1 if we couldn't locate it

Definition at line 736 of file kresolver.cpp.

resolve()

KResolverResults KResolver::resolve ( const TQString &  host, const TQString &  service, int  flags = 0, int  families = KResolver::InternetFamily  )

static

Resolve the nodename and service name synchronously.

This static function is provided as convenience for simplifying name resolution. It resolves the given host and service names synchronously and returns the results it found. It is equivalent to the following code:

KResolver qres(host, service);
qres.setFlags(flags);
qres.setFamily(families)
qres.start();
qres.wait();
return qres.results();

Parameters

host	the nodename to resolve
service	the service to resolve
flags	flags to be used
families	the families to be searched

Returns

a KResolverResults object containing the results

See also

KResolverResults for information on how to obtain the error code

Definition at line 591 of file kresolver.cpp.

resolveAsync()

bool KResolver::resolveAsync ( TQObject *  userObj, const char *  userSlot, const TQString &  host, const TQString &  service, int  flags = 0, int  families = KResolver::InternetFamily  )

static

Start an asynchronous name resolution.

This function is provided as a convenience to simplify the resolution process. It creates an internal KResolver object, connects the finished signal to the given slot and starts the resolution asynchronously. It is more or less equivalent to the following code:

Note: this function may trigger the signal before it returns, so your code must be prepared for this situation.

KResolver* qres = new KResolver(host, service);
TQObject::connect(qres, TQ_SIGNAL(finished(KResolverResults)),
        userObj, userSlot);
qres->setFlags(flags);
qres->setFamily(families);
return qres->start();

You should use it like this in your code:

KResolver::resolveAsync(myObj, TQ_SLOT(mySlot(KResolverResults)), host, service);

Parameters

userObj	the object whose slot userSlot we will connect
userSlot	the slot to which we'll connect
host	the nodename to resolve
service	the service to resolve
flags	flags to be used
families	families to be searcheed

Returns

true if the queueing was successful, false if not

See also

KResolverResults for information on how to obtain the error code

Definition at line 602 of file kresolver.cpp.

results()

KResolverResults KResolver::results

(

)

const

Retrieves the results of this resolution.

Use this function to retrieve the results of the resolution. If no data was resolved (yet) or if we failed, this function will return an empty object.

Returns

the resolved data

See also

status for information on finding out if the resolution was successful

Definition at line 520 of file kresolver.cpp.

serviceName() [1/3]

TQString KResolver::serviceName

(

)

const

The service name to which the resolution was/is to be performed.

Definition at line 346 of file kresolver.cpp.

serviceName() [2/3]

TQStrList KResolver::serviceName ( const char *  servname, const char *  protoname  )

static

Finds all the aliases for a given service name.

Note: the returned TQStrList operates on deep-copies.

Parameters

servname	the service alias to be looked for
protoname	the protocol it is associated with

Returns

all the service names in a list. The first is the "proper" name.

Definition at line 849 of file kresolver.cpp.

serviceName() [3/3]

TQStrList KResolver::serviceName ( int  port, const char *  protoname  )

static

Resolves a port number to its names.

Note: the returned TQStrList operates on deep copies.

Parameters

port	the port number, in host byte-order
protoname	the protocol it is associated with

Returns

all the service names in a list. The first is the "proper" name.

Definition at line 909 of file kresolver.cpp.

servicePort()

int KResolver::servicePort ( const char *  servname, const char *  protoname  )

static

Resolves a service name to its port number.

Parameters

servname	the service name to be looked for
protoname	the protocol it is associated with

Returns

the port number in host byte-order or -1 in case of error

Definition at line 793 of file kresolver.cpp.

setAddress()

void KResolver::setAddress	(	const TQString &	node,
		const TQString &	service
	)

Sets both the host and the service names.

Setting either value to TQString::null will unset them.

Parameters

node	The nodename
service	The service name

Definition at line 376 of file kresolver.cpp.

setError()

void KNetwork::KResolver::setError ( int  errorcode, int  systemerror = 0  )

protected

Sets the error codes.

setFamily()

void KResolver::setFamily

(

int

families

)

Sets the allowed socket families.

Parameters

families

the families that we want/accept

See also

SocketFamilies for possible values

Definition at line 401 of file kresolver.cpp.

setFlags()

int KResolver::setFlags

(

int

flags

)

Sets the flags.

Parameters

flags

the new flags

Returns

the old flags

See also

Flags for an explanation on the flags

Definition at line 389 of file kresolver.cpp.

setNodeName()

void KResolver::setNodeName

(

const TQString &

nodename

)

Sets the nodename for the resolution.

Set the nodename to TQString::null to unset it.

Parameters

nodename

The nodename to be resolved.

Definition at line 352 of file kresolver.cpp.

setProtocol()

void KResolver::setProtocol	(	int	protonum,
		const char *	name = 0L
	)

Sets the protocol we want.

Protocols are dependant on the selected address family, so you should know what you are doing if you use this function. Besides, protocols generally are either stream-based or datagram-based, so the value of the socket type is also important. The resolution will fail if these values don't match.

When using an Internet socket, the values for the protocol are the IPPROTO_* constants, defined in <netinet/in.h>.

You may choose to set the protocol either by its number or by its name, or by both. If you set:

• the number and the name: both values will be stored internally; you may set the name to an empty value, if wanted
• the number only (name = NULL): the name will be searched in the protocols database
• the name only (number = 0): the number will be searched in the database
• neither name nor number: reset to default behaviour

Parameters

protonum	the protocol number we want
name	the protocol name

Definition at line 421 of file kresolver.cpp.

setServiceName()

void KResolver::setServiceName

(

const TQString &

service

)

Sets the service name to be resolved.

Set it to TQString::null to unset it.

Parameters

service

The service to be resolved.

Definition at line 364 of file kresolver.cpp.

setSocketType()

void KResolver::setSocketType

(

int

type

)

Sets the socket type we want.

The values for the type parameter are the SOCK_* constants, defined in <sys/socket.h>. The most common values are:

• SOCK_STREAM streaming socket (= reliable, sequenced, connection-based)
• SOCK_DGRAM datagram socket (= unreliable, connectionless)
• SOCK_RAW raw socket, with direct access to the container protocol (such as IP)

These three are the only values to which it is guaranteed that resolution will work. Some systems may define other constants (such as SOCK_RDM for reliable datagrams), but support is implementation-defined.

Parameters

type	the wanted socket type (SOCK_* constants). Set 0 to use the default.

Definition at line 411 of file kresolver.cpp.

start()

bool KResolver::start

(

)

Starts the name resolution asynchronously.

This function will queue this object for resolution and will return immediately. The status upon exit will either be Queued or InProgress or Failed.

This function does nothing if the object is already queued. But if it had already succeeded or failed, this function will re-start it.

Note: if both the nodename and the servicename are unset, this function will not queue, but will set a success state and emit the signal. Also note that in this case and maybe others, the signal finished might be emitted before this function returns.

Returns

true if this request was successfully queued for asynchronous resolution

Definition at line 442 of file kresolver.cpp.

status()

int KResolver::status

(

)

const

Retrieve the current status of this object.

See also

StatusCodes for the possible status codes.

Definition at line 316 of file kresolver.cpp.

systemError()

int KResolver::systemError

(

)

const

Retrieve the associated system error code in this object.

Many resolution operations may generate an extra error code as given by the C errno variable. That value is stored in the object and can be retrieved by this function.

Definition at line 328 of file kresolver.cpp.

virtual_hook()

void KResolver::virtual_hook ( int  id, void *  data  )

protectedvirtual

Definition at line 1124 of file kresolver.cpp.

wait()

bool KResolver::wait

(

int

msec = 0

)

Waits for a request to finish resolving.

This function will wait on a running request for its termination. The status upon exit will either be Success or Failed or Canceled.

This function may be called from any thread, even one that is not the GUI thread or the one that started the resolution process. But note this function is not thread-safe nor reentrant: i.e., only one thread can be waiting on one given object.

Also note that this function ensures that the finished signal is emitted before it returns. That means that, as a side-effect, whenever wait() is called, the signal is emitted on the thread calling wait().

Parameters

msec	the time to wait, in milliseconds or 0 to wait forever

Returns

true if the resolution has finished processing, even when it failed or was canceled. False means the wait timed out and the resolution is still running.

Definition at line 461 of file kresolver.cpp.

Friends And Related Function Documentation

::KNetwork::Internal::KResolverManager

friend class ::KNetwork::Internal::KResolverManager

friend

Definition at line 939 of file kresolver.h.

KResolverResults

friend class KResolverResults

friend

Definition at line 938 of file kresolver.h.

---

The documentation for this class was generated from the following files:

• kresolver.h
• kresolver.cpp