KDNSSD 5.109.0
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Browses for network services advertised over DNS-SD. More...
#include <KDNSSD/ServiceBrowser>
Public Types | |
enum | State { Working , Stopped , Unsupported } |
Availability of DNS-SD services. More... | |
Signals | |
void | finished () |
Emitted when the list of published services has settled. | |
void | serviceAdded (KDNSSD::RemoteService::Ptr service) |
Emitted when new service is discovered. | |
void | serviceRemoved (KDNSSD::RemoteService::Ptr service) |
Emitted when a service is no longer published over DNS-SD. | |
Public Member Functions | |
ServiceBrowser (const QString &type, bool autoResolve=false, const QString &domain=QString(), const QString &subtype=QString()) | |
Create a ServiceBrowser for a particular service type. | |
bool | isAutoResolving () const |
Whether discovered services are resolved before being reported. | |
QList< RemoteService::Ptr > | services () const |
The currently known services of the specified type. | |
virtual void | startBrowse () |
Starts browsing for services. | |
Static Public Member Functions | |
static QString | getLocalHostName () |
The mDNS hostname of the local machine. | |
static State | isAvailable () |
Checks availability of DNS-SD services. | |
static QHostAddress | resolveHostName (const QString &hostname) |
Resolves an mDNS hostname into an IP address. | |
Protected Member Functions | |
virtual void | virtual_hook (int, void *) |
Browses for network services advertised over DNS-SD.
This is the central class in the KDNSSD library for applications that want to discover services on network.
Suppose that you need list of web servers running. Then you might do something like
In above example addService() will be called for every web server already running and for every web service that subsequently appears on the network and delService() will be called when a server previously advertised is stopped.
Because no domain was passed to constructor, the default domain will be searched. To find other domains to browse for services on, use DomainBrowser.
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explicit |
Create a ServiceBrowser for a particular service type.
DomainBrowser can be used to find other domains to browse on. If no domain is given, the default domain is used.
The service type is the high-level protocol type, followed by a dot, followed by the transport protocol type (_tcp
or _udp
). The DNS-SD website maintains a full list of service types.
The subtype
parameter allows you to do more fine-grained filtering on the services you are interested in. So you might request only FTP servers that allow anonymous access by passing "_ftp._tcp" as the type
and "_anon" as the subtype
. Subtypes are particularly important for types like _soap and _upnp, which are far too generic for most applications. In these cases, the subtype can be used to specify the particular SOAP or UPnP protocol they want.
autoResolve
will increase network usage by resolving all services, so this feature should be used only when necessary.type | service types to browse for (example: "_http._tcp") |
autoResolve | discovered services will be resolved before being reported with the serviceAdded() signal |
domain | a domain to search on instead of the default one |
subtype | only browse for a specific subtype |
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signal |
Emitted when the list of published services has settled.
This signal is emitted once after startBrowse() is called when all the services of the requested type that are currently published have been reported (even if none are available or the DNS-SD service is not available). It is emitted again when a new batch of services become available or disappear.
For example, if a new host is connected to network and announces some services watched for by this ServiceBrowser, they will be reported by one or more serviceAdded() signals and the whole batch will be concluded by finished().
This signal can be used by applications that just want to get a list of the currently available services (similar to a directory listing) and do not care about adding or removing services that appear or disappear later.
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static |
The mDNS hostname of the local machine.
Usually this will return the same as QHostInfo::localHostName(), but it may be changed to something different in the Avahi configuration file (if using the Avahi backend).
bool KDNSSD::ServiceBrowser::isAutoResolving | ( | ) | const |
Whether discovered services are resolved before being reported.
autoResolve
parameter passed to the constructor
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static |
Checks availability of DNS-SD services.
Although this method is part of ServiceBrowser, none of the classes in this library will be able to perform their intended function if this method does not return Working.
If this method does not return Working, it is still safe to call any of the methods in this library. However, no services will be found or published and no domains will be found.
If you use this function to report an error to the user, below is a suggestion on how to word the errors when publishing a service. The first line of each error message can also be used for reporting errors when browsing for services.
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static |
Resolves an mDNS hostname into an IP address.
This function is very rarely useful, since a properly configured system is able to resolve an mDNS-based host name using the system resolver (ie: you can just pass the mDNS hostname to KIO or other library).
hostname | the hostname to be resolved |
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signal |
Emitted when new service is discovered.
If isAutoResolving() returns true
, this will not be emitted until the service has been resolved.
service | a RemoteService object describing the service |
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signal |
Emitted when a service is no longer published over DNS-SD.
The RemoteService object is removed from the services() list and deleted immediately after this signal returns.
service | a RemoteService object describing the service |
QList< RemoteService::Ptr > KDNSSD::ServiceBrowser::services | ( | ) | const |
The currently known services of the specified type.
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virtual |
Starts browsing for services.
Only the first call to this function will have any effect.
Browsing stops when the ServiceBrowser object is destroyed.