mx.messaging.channels.HTTPChannel - Adobe® Flex® 4 Language Reference (Flex 4)

Package	mx.messaging.channels
Class	public class HTTPChannel
Inheritance	HTTPChannel PollingChannel Channel EventDispatcher Object
Subclasses	SecureHTTPChannel, StreamingHTTPChannel

Language Version:

ActionScript 3.0

Product Versions:

BlazeDS 4, LiveCycle Data Services 3

Runtime Versions:

Flash Player 9, AIR 1.1

The HTTPChannel class provides the HTTP support for messaging. You can configure this Channel to poll the server at an interval to approximate server push. You can also use this Channel with polling disabled to send RPC messages to remote destinations to invoke their methods.

The HTTPChannel relies on network services native to Flash Player and AIR, and exposed to ActionScript by the URLLoader class. This channel uses URLLoader exclusively, and creates a new URLLoader per request.

Channels are created within the framework using the ServerConfig.getChannel() method. Channels can be constructed directly and assigned to a ChannelSet if desired.

Channels represent a physical connection to a remote endpoint. Channels are shared across destinations by default. This means that a client targetting different destinations may use the same Channel to communicate with these destinations.

When used in polling mode, this Channel polls the server for new messages based on the polling-interval-seconds property in the configuration file, and this can be changed by setting the pollingInterval property. The default value is 3 seconds. To enable polling, the channel must be connected and the polling-enabled property in the configuration file must be set to true, or the pollingEnabled property of the Channel must be set to true.

Public Properties

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	Property		Defined By
		authenticated : Boolean [read-only] Indicates if this channel is authenticated.	Channel
		channelSets : Array [read-only] Provides access to the ChannelSets connected to the Channel.	Channel
		connected : Boolean [read-only] Indicates whether this channel has established a connection to the remote destination.	Channel
		connectTimeout : int Provides access to the connect timeout in seconds for the channel.	Channel
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		endpoint : String [read-only] Provides access to the endpoint for this channel.	Channel
		failoverURIs : Array Provides access to the set of endpoint URIs that this channel can attempt to failover to if the endpoint is clustered.	Channel
		id : String Provides access to the id of this channel.	Channel
		piggybackingEnabled : Boolean Indicates whether this channel will piggyback poll requests along with regular outbound messages when an outstanding poll is not in progress.	HTTPChannel
		polling : Boolean [read-only] Reports whether the channel is actively polling.	HTTPChannel
		pollingEnabled : Boolean Indicates whether this channel is enabled to poll.	HTTPChannel
		pollingInterval : Number Provides access to the polling interval for this Channel.	HTTPChannel
		protocol : String [override] [read-only] Returns the protocol for this channel (http).	HTTPChannel
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object
		reconnecting : Boolean [read-only] Indicates whether this channel is in the process of reconnecting to an alternate endpoint.	Channel
		recordMessageSizes : Boolean [read-only] Channel property determines the level of performance information injection - whether we inject message sizes or not.	Channel
		recordMessageTimes : Boolean [read-only] Channel property determines the level of performance information injection - whether we inject timestamps or not.	Channel
		requestTimeout : int Provides access to the default request timeout in seconds for the channel.	Channel
		uri : String Provides access to the URI used to create the whole endpoint URI for this channel.	Channel

Protected Properties

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	Property		Defined By
		shouldBeConnected : Boolean [read-only] Indicates whether this channel should be connected to its endpoint.	Channel

Public Methods

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	Method		Defined By
		HTTPChannel(id:String = null, uri:String = null) Constructor.	HTTPChannel
		addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.	EventDispatcher
		applySettings(settings:XML):void Subclasses should override this method to apply any settings that may be necessary for an individual channel.	Channel
		connect(channelSet:ChannelSet):void Connects the ChannelSet to the Channel.	Channel
		disablePolling():void Disables polling based on the number of times enablePolling() and disablePolling() have been invoked.	PollingChannel
		disconnect(channelSet:ChannelSet):void Disconnects the ChannelSet from the Channel.	Channel
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	EventDispatcher
		enablePolling():void Enables polling based on the number of times enablePolling() and disablePolling() have been invoked.	PollingChannel
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	EventDispatcher
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		logout(agent:MessageAgent):void Sends a CommandMessage to the server to logout if the Channel is connected.	Channel
		poll():void Initiates a poll operation if there are consumers subscribed to this channel, and polling is enabled for this channel.	PollingChannel
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	EventDispatcher
		send(agent:MessageAgent, message:IMessage):void [override] Sends the specified message to its target destination.	PollingChannel
		setCredentials(credentials:String, agent:MessageAgent = null, charset:String = null):void Sets the credentials to the specified value.	Channel
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns the string representation of the specified object.	Object
		valueOf():Object Returns the primitive value of the specified object.	Object
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	EventDispatcher

Protected Methods

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	Method		Defined By
		applyClientLoadBalancingSettings(props:XML):void Applies the client load balancing urls if they exists.	Channel
		connectFailed(event:ChannelFaultEvent):void Processes a failed internal connect and dispatches the FAULT event for the channel.	Channel
		connectSuccess():void Processes a successful internal connect and dispatches the CONNECT event for the Channel.	Channel
		connectTimeoutHandler(event:flash.events:TimerEvent):void Handles a connect timeout by dispatching a ChannelFaultEvent.	Channel
		disconnectFailed(event:ChannelFaultEvent):void Processes a failed internal disconnect and dispatches the FAULT event for the channel.	Channel
		disconnectSuccess(rejected:Boolean = false):void Processes a successful internal disconnect and dispatches the DISCONNECT event for the Channel.	Channel
		flexClientWaitHandler(event:PropertyChangeEvent):void Handles a change to the guard condition for managing initial Channel connect for the application.	Channel
		getMessageResponder(agent:MessageAgent, message:IMessage):MessageResponder Returns the appropriate MessageResponder for the Channel's send() method.	Channel
		internalConnect():void Connects the Channel to its endpoint.	Channel
		internalDisconnect(rejected:Boolean = false):void Disconnects the Channel from its endpoint.	Channel
		internalSend(messageResponder:MessageResponder):void Sends the Message out over the Channel and routes the response to the responder.	Channel

Events

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	Summary	Defined By
activate	[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.	EventDispatcher
channelConnect	Dispatched after the channel has connected to its endpoint.	Channel
channelDisconnect	Dispatched after the channel has disconnected from its endpoint.	Channel
channelFault	Dispatched after the channel has faulted.	Channel
deactivate	[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.	EventDispatcher
message	Dispatched when a channel receives a message from its endpoint.	Channel
propertyChange	Dispatched when a property of the channel changes.	Channel

Property Detail

piggybackingEnabled

property

piggybackingEnabled:Boolean

Language Version:

ActionScript 3.0

Product Versions:

BlazeDS 4, LiveCycle Data Services 3

Runtime Versions:

Flash Player 9, AIR 1.1

Indicates whether this channel will piggyback poll requests along with regular outbound messages when an outstanding poll is not in progress. This allows the server to piggyback data for the client along with its response to client's message.

Implementation
public function get piggybackingEnabled():Boolean
public function set piggybackingEnabled(value:Boolean):void

polling

property

polling:Boolean [read-only]

Language Version:

ActionScript 3.0

Product Versions:

BlazeDS 4, LiveCycle Data Services 3

Runtime Versions:

Flash Player 9, AIR 1.1

Reports whether the channel is actively polling.

Implementation
public function get polling():Boolean

pollingEnabled

property

pollingEnabled:Boolean

Language Version:

ActionScript 3.0

Product Versions:

BlazeDS 4, LiveCycle Data Services 3

Runtime Versions:

Flash Player 9, AIR 1.1

Indicates whether this channel is enabled to poll.

Implementation
public function get pollingEnabled():Boolean
public function set pollingEnabled(value:Boolean):void

pollingInterval

property

pollingInterval:Number

Language Version:

ActionScript 3.0

Product Versions:

BlazeDS 4, LiveCycle Data Services 3

Runtime Versions:

Flash Player 9, AIR 1.1

Provides access to the polling interval for this Channel. The value is in milliseconds. This value determines how often this Channel requests messages from the server, to approximate server push.

Implementation
public function get pollingInterval():Number
public function set pollingInterval(value:Number):void

Throws

ArgumentError — If the pollingInterval is assigned a value of 0 or less.

protocol

property

protocol:String [read-only] [override]

Language Version:

ActionScript 3.0

Product Versions:

BlazeDS 4, LiveCycle Data Services 3

Runtime Versions:

Flash Player 9, AIR 1.1

Returns the protocol for this channel (http).

Implementation
override public function get protocol():String

Constructor Detail

HTTPChannel

()

Constructor

public function HTTPChannel(id:String = null, uri:String = null)

Language Version:

ActionScript 3.0

Product Versions:

BlazeDS 4, LiveCycle Data Services 3

Runtime Versions:

Flash Player 9, AIR 1.1

Constructor.

Parameters

	`id:String` (default = `null`) — The id of this Channel.

	`uri:String` (default = `null`) — The uri for this Channel.