Adobe® Flex® 4 Language Reference
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flash.net 
URLRequestHeader 
Packageflash.net
Classpublic final class URLRequestHeader
InheritanceURLRequestHeader Inheritance Object

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

A URLRequestHeader object encapsulates a single HTTP request header and consists of a name/value pair. URLRequestHeader objects are used in the requestHeaders property of the URLRequest class.

In Adobe® AIR®, content in the application security sandbox (such as content installed with the AIR application) can use any request headers, without error. However, for content running in Adobe AIR that is in a different security sandbox, or for content running in Flash® Player, using following request headers cause a runtime error to be thrown, and the restricted terms are not case-sensitive (for example, Get, get, and GET are each not allowed):

In Flash Player and in Adobe AIR content outside of the application security sandbox, the following request headers cannot be used, and the restricted terms are not case-sensitive (for example, Get, get, and GET are all not allowed). Also, hyphenated terms apply if an underscore character is used (for example, both Content-Length and Content_Length are not allowed):

Accept-Charset, Accept-Encoding, Accept-Ranges, Age, Allow, Allowed, Authorization, Charge-To, Connect, Connection, Content-Length, Content-Location, Content-Range, Cookie, Date, Delete, ETag, Expect, Get, Head, Host, If-Modified-Since, Keep-Alive, Last-Modified, Location, Max-Forwards, Options, Origin, Post, Proxy-Authenticate, Proxy-Authorization, Proxy-Connection, Public, Put, Range, Referer, Request-Range, Retry-After, Server, TE, Trace, Trailer, Transfer-Encoding, Upgrade, URI, User-Agent, Vary, Via, Warning, WWW-Authenticate, x-flash-version.

URLRequestHeader objects are restricted in length. If the cumulative length of a URLRequestHeader object (the length of the name property plus the value property) or an array of URLRequestHeader objects used in the URLRequest.requestHeaders property exceeds the acceptable length, an exception is thrown.

Content running in Adobe AIR sets the ACCEPT header to the following, unless you specify a setting for the ACCEPT header in the requestHeaders property of the URLRequest class:

text/xml, application/xml, application/xhtml+xml, text/html;q=0.9, text/plain;q=0.8, image/png, application/x-shockwave-flash, video/mp4;q=0.9, flv-application/octet-stream;q=0.8, video/x-flv;q=0.7, audio/mp4, */*;q=0.5

Not all methods that accept URLRequest parameters support the requestHeaders property, consult the documentation for the method you are calling. For example, the FileReference.upload() and FileReference.download() methods do not support the URLRequest.requestHeaders property.

Due to browser limitations, custom HTTP request headers are only supported for POST requests, not for GET requests.

View the examples

See also



Public Properties
 PropertyDefined By
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
  name : String
An HTTP request header name (such as Content-Type or SOAPAction).
URLRequestHeader
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
Object
  value : String
The value associated with the name property (such as text/plain).
URLRequestHeader
Public Methods
 MethodDefined By
  
URLRequestHeader(name:String = "", value:String = "")
Creates a new URLRequestHeader object that encapsulates a single HTTP request header.
URLRequestHeader
 Inherited
Indicates whether an object has a specified property defined.
Object
 Inherited
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
 Inherited
Indicates whether the specified property exists and is enumerable.
Object
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
Returns the string representation of the specified object.
Object
 Inherited
Returns the primitive value of the specified object.
Object
Property Detail

name

property
public var name:String

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

An HTTP request header name (such as Content-Type or SOAPAction).

value

property 
public var value:String

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The value associated with the name property (such as text/plain).

Constructor Detail

URLRequestHeader

()Constructor
public function URLRequestHeader(name:String = "", value:String = "")

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

Creates a new URLRequestHeader object that encapsulates a single HTTP request header. URLRequestHeader objects are used in the requestHeaders property of the URLRequest class.

Parameters
name:String (default = "") — An HTTP request header name (such as Content-Type or SOAPAction).
 
value:String (default = "") — The value associated with the name property (such as text/plain).
URLRequestHeaderExample.as

The following example adds a single HTTP request header header to the array for the requestHeaders property. The header indicates that the application should forward the request to the origin server even if it has a cached copy of what is being requested.
package {
    import flash.display.Sprite;
    import flash.events.*;
    import flash.net.URLLoader;
    import flash.net.URLRequest;
    import flash.net.URLRequestHeader;
    import flash.net.URLRequestMethod;
    import flash.net.URLVariables;

    public class URLRequestHeaderExample extends Sprite {
        public function URLRequestHeaderExample() {
            var loader:URLLoader = new URLLoader();
            configureListeners(loader);

            var header:URLRequestHeader = new URLRequestHeader("pragma", "no-cache");
            var request:URLRequest = new URLRequest("http://www.[yourdomain].com/greeting.cfm");
            request.data = new URLVariables("name=John+Doe");
            request.method = URLRequestMethod.POST;
            request.requestHeaders.push(header);
            try {
                loader.load(request);
            } catch (error:Error) {
                trace("Unable to load requested document.");
            }
        }

        private function configureListeners(dispatcher:IEventDispatcher):void {
            dispatcher.addEventListener(Event.COMPLETE, completeHandler);
            dispatcher.addEventListener(Event.OPEN, openHandler);
            dispatcher.addEventListener(ProgressEvent.PROGRESS, progressHandler);
            dispatcher.addEventListener(SecurityErrorEvent.SECURITY_ERROR, securityErrorHandler);
            dispatcher.addEventListener(HTTPStatusEvent.HTTP_STATUS, httpStatusHandler);
            dispatcher.addEventListener(IOErrorEvent.IO_ERROR, ioErrorHandler);
        }

        private function completeHandler(event:Event):void {
            var loader:URLLoader = URLLoader(event.target);
            trace("completeHandler: " + loader.data);
        }

        private function openHandler(event:Event):void {
            trace("openHandler: " + event);
        }

        private function progressHandler(event:ProgressEvent):void {
            trace("progressHandler loaded:" + event.bytesLoaded + " total: " + event.bytesTotal);
        }

        private function securityErrorHandler(event:SecurityErrorEvent):void {
            trace("securityErrorHandler: " + event);
        }

        private function httpStatusHandler(event:HTTPStatusEvent):void {
            trace("httpStatusHandler: " + event);
        }

        private function ioErrorHandler(event:IOErrorEvent):void {
            trace("ioErrorHandler: " + event);
        }
    }
}