View source

class DNSResolver

package openfl.net.dns

extends EventDispatcher

Available on AIR, Android, HashLink, Linux, Neko, Windows, iOS, macOS

The DNSResolver class lets you lookup Domain Name System (DNS) resource records.

You can test for support at run time using the DNSResolver.isSupported property.

OpenFL target support: Not currently supported, except when targeting AIR.

Adobe AIR profile support: This feature is supported on all desktop operating systems, but is not supported on mobile devices. It is partially supported on AIR for TV devices.See AIR Profile Support for more information regarding API support across multiple profiles.

You can look up the following types of resource records:

  • ARecord: IPv4 address for a host.
  • AAAARecord: IPv6 address for a host.
  • MXRecord: mail exchange record for a host.
  • PTRRecord: host name for an IP address.
  • SRVRecord: service record for a service

The following table indicates DNS lookup support on AIR for TV devices. Unsupported requests result in the DNSResolver object dispatching an flash.events.ErrorEvent object.

Record type specified in DNSResolver.lookup()Support
ARecordFull support
AAAARecordFull support
MXRecordNot supported
PTRRecordSupported only for IPv4 addresses, not for IPv6 addresses
SRVRecordNot supported

Static variables

staticread onlyisSupported:Bool

Indicates whether DNS lookups are supported on the client system.

Constructor

new()

Creates a DNSResolver object.

Methods

lookup(host:String, recordType:Class<ResourceRecord>):Void

Looks up a DNS resource record based on a query string.

The lookup() method performs a DNS lookup asynchronously. Listen for the lookup event to get the results of the lookup. Listen for the error event to receive errors. Results are dispatched in a DNSResolverEvent object.

To specify the type of resource record to look up, pass the corresponding class in the recordType parameter. (Pass the class name itself and not a string containing the class name.)

The content of the query string passed to the method depends on the type of resource record being looked up. The following list illustrates the query string to use for each record type.

Record typeQuery stringExample
ARecordhost name"example.com"
AAAARecordhost name"example.com"
MXRecordhost name"example.com"
PTRRecordIP address"208.77.188.166"
SRVRecord_service._protocol.host."_sip._tcp.example.com."

Inherited Variables

Inherited Methods

Defined by EventDispatcher

@:value({ useWeakReference : false, priority : 0, useCapture : false })addEventListener<T>(type:EventType<T>, listener:T ‑> Void, useCapture:Bool = false, priority:Int = 0, useWeakReference:Bool = false):Void

Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event. You can register event listeners on all nodes in the display list for a specific type of event, phase, and priority.

After you successfully register an event listener, you cannot change its priority through additional calls to addEventListener(). To change a listener's priority, you must first call removeListener(). Then you can register the listener again with the new priority level.

Keep in mind that after the listener is registered, subsequent calls to addEventListener() with a different type or useCapture value result in the creation of a separate listener registration. For example, if you first register a listener with useCapture set to true, it listens only during the capture phase. If you call addEventListener() again using the same listener object, but with useCapture set to false, you have two separate listeners: one that listens during the capture phase and another that listens during the target and bubbling phases.

You cannot register an event listener for only the target phase or the bubbling phase. Those phases are coupled during registration because bubbling applies only to the ancestors of the target node.

If you no longer need an event listener, remove it by calling removeEventListener(), or memory problems could result. Event listeners are not automatically removed from memory because the garbage collector does not remove the listener as long as the dispatching object exists(unless the useWeakReference parameter is set to true).

Copying an EventDispatcher instance does not copy the event listeners attached to it.(If your newly created node needs an event listener, you must attach the listener after creating the node.) However, if you move an EventDispatcher instance, the event listeners attached to it move along with it.

If the event listener is being registered on a node while an event is being processed on this node, the event listener is not triggered during the current phase but can be triggered during a later phase in the event flow, such as the bubbling phase.

If an event listener is removed from a node while an event is being processed on the node, it is still triggered by the current actions. After it is removed, the event listener is never invoked again(unless registered again for future processing).

Parameters:

type

The type of event.

useCapture

Determines whether the listener works in the capture phase or the target and bubbling phases. If useCapture is set to true, the listener processes the event only during the capture phase and not in the target or bubbling phase. If useCapture is false, the listener processes the event only during the target or bubbling phase. To listen for the event in all three phases, call addEventListener twice, once with useCapture set to true, then again with useCapture set to false.

priority

The priority level of the event listener. The priority is designated by a signed 32-bit integer. The higher the number, the higher the priority. All listeners with priority n are processed before listeners of priority n-1. If two or more listeners share the same priority, they are processed in the order in which they were added. The default priority is 0.

useWeakReference

Determines whether the reference to the listener is strong or weak. A strong reference(the default) prevents your listener from being garbage-collected. A weak reference does not.

Class-level member functions are not subject to garbage collection, so you can set useWeakReference to true for class-level member functions without subjecting them to garbage collection. If you set useWeakReference to true for a listener that is a nested inner function, the function will be garbage-collected and no longer persistent. If you create references to the inner function (save it in another variable) then it is not garbage-collected and stays persistent.

Weak references are supported on some OpenFL targets only, including html5, cpp, and flash/air. On other targets, this parameter is ignored, and the reference will be strong instead.

Throws:

ArgumentError

The listener specified is not a function.

dispatchEvent(event:Event):Bool

Dispatches an event into the event flow. The event target is the EventDispatcher object upon which the dispatchEvent() method is called.

Parameters:

event

The Event object that is dispatched into the event flow. If the event is being redispatched, a clone of the event is created automatically. After an event is dispatched, its target property cannot be changed, so you must create a new copy of the event for redispatching to work.

Returns:

A value of true if the event was successfully dispatched. A value of false indicates failure or that preventDefault() was called on the event.

Throws:

Error

The event dispatch recursion limit has been reached.

hasEventListener(type:String):Bool

Checks whether the EventDispatcher object has any listeners registered for a specific type of event. This allows you to determine where an EventDispatcher object has altered handling of an event type in the event flow hierarchy. To determine whether a specific event type actually triggers an event listener, use willTrigger().

The difference between hasEventListener() and willTrigger() is that hasEventListener() examines only the object to which it belongs, whereas willTrigger() examines the entire event flow for the event specified by the type parameter.

When hasEventListener() is called from a LoaderInfo object, only the listeners that the caller can access are considered.

Parameters:

type

The type of event.

Returns:

A value of true if a listener of the specified type is registered; false otherwise.

@:value({ useCapture : false })removeEventListener<T>(type:EventType<T>, listener:T ‑> Void, useCapture:Bool = false):Void

Removes a listener from the EventDispatcher object. If there is no matching listener registered with the EventDispatcher object, a call to this method has no effect.

Parameters:

type

The type of event.

useCapture

Specifies whether the listener was registered for the capture phase or the target and bubbling phases. If the listener was registered for both the capture phase and the target and bubbling phases, two calls to removeEventListener() are required to remove both, one call with useCapture() set to true, and another call with useCapture() set to false.

toString():String

willTrigger(type:String):Bool

Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type. This method returns true if an event listener is triggered during any phase of the event flow when an event of the specified type is dispatched to this EventDispatcher object or any of its descendants.

The difference between the hasEventListener() and the willTrigger() methods is that hasEventListener() examines only the object to which it belongs, whereas the willTrigger() method examines the entire event flow for the event specified by the type parameter.

When willTrigger() is called from a LoaderInfo object, only the listeners that the caller can access are considered.

Parameters:

type

The type of event.

Returns:

A value of true if a listener of the specified type will be triggered; false otherwise.