URLStream  - AS3

Returns the number of bytes of data available for reading in the input buffer. Your code must call the bytesAvailable property to ensure that sufficient data is available before you try to read it with one of the read methods.

Indicates whether this URLStream object is currently connected. A call to this property returns a value of true if the URLStream object is connected, or false otherwise.

Indicates the byte order for the data. Possible values are Endian.BIG_ENDIAN or Endian.LITTLE_ENDIAN.

The default value is Endian.BIG_ENDIAN.

Related API Elements

Controls the version of Action Message Format (AMF) used when writing or reading an object.

Related API Elements

Immediately closes the stream and cancels the download operation. No data can be read from the stream after the close() method is called.

Begins downloading the URL specified in the request parameter.

Note: If a file being loaded contains non-ASCII characters (as found in many non-English languages), it is recommended that you save the file with UTF-8 or UTF-16 encoding, as opposed to a non-Unicode format like ASCII.

If the loading operation fails immediately, an IOError or SecurityError (including the local file security error) exception is thrown describing the failure. Otherwise, an open event is dispatched if the URL download starts downloading successfully, or an error event is dispatched if an error occurs.

By default, the calling SWF file and the URL you load must be in exactly the same domain. For example, a SWF file at www.adobe.com can load data only from sources that are also at www.adobe.com. To load data from a different domain, place a URL policy file on the server hosting the data.

In Flash Player, you cannot connect to commonly reserved ports. For a complete list of blocked ports, see "Restricting Networking APIs" in the ActionScript 3.0 Developer's Guide.

In Flash Player, you can prevent a SWF file from using this method by setting the allowNetworking parameter of the the object and embed tags in the HTML page that contains the SWF content.

In Flash Player 10 and later, and in AIR 1.5 and later, if you use a multipart Content-Type (for example "multipart/form-data") that contains an upload (indicated by a "filename" parameter in a "content-disposition" header within the POST body), the POST operation is subject to the security rules applied to uploads:

• The POST operation must be performed in response to a user-initiated action, such as a mouse click or key press.
• If the POST operation is cross-domain (the POST target is not on the same server as the SWF file that is sending the POST request), the target server must provide a URL policy file that permits cross-domain access.

Also, for any multipart Content-Type, the syntax must be valid (according to the RFC2046 standards). If the syntax appears to be invalid, the POST operation is subject to the security rules applied to uploads.

These rules also apply to AIR content in non-application sandboxes. However, in Adobe AIR, content in the application sandbox (content installed with the AIR application) are not restricted by these security limitations.

For more information related to security, see The Flash Player Developer Center Topic: Security.

In AIR, a URLRequest object can register for the httpResponse status event. Unlike the httpStatus event, the httpResponseStatus event is delivered before any response data. Also, the httpResponseStatus event includes values for the responseHeaders and responseURL properties (which are undefined for an httpStatus event. Note that the httpResponseStatus event (if any) will be sent before (and in addition to) any complete or error event.

If there is an httpResponseStatus event listener, the body of the response message is always sent; and HTTP status code responses always results in a complete event. This is true in spite of whether the HTTP response status code indicates a success or an error.

In AIR, if there is no httpResponseStatus event listener, the behavior differs based on the SWF version:

• For SWF 9 content, the body of the HTTP response message is sent only if the HTTP response status code indicates success. Otherwise (if there is an error), no body is sent and the URLRequest object dispatches an IOError event.
• For SWF 10 content, the body of the HTTP response message is always sent. If there is an error, the URLRequest object dispatches an IOError event.

Parameters

Reads a Boolean value from the stream. A single byte is read, and true is returned if the byte is nonzero, false otherwise.

Reads a signed byte from the stream.

The returned value is in the range -128...127.

Reads length bytes of data from the stream. The bytes are read into the ByteArray object specified by bytes, starting offset bytes into the ByteArray object.

Parameters

Reads an IEEE 754 double-precision floating-point number from the stream.

Reads an IEEE 754 single-precision floating-point number from the stream.

Reads a signed 32-bit integer from the stream.

The returned value is in the range -2147483648...2147483647.

Reads a multibyte string of specified length from the byte stream using the specified character set.

Parameters

Reads an object from the socket, encoded in Action Message Format (AMF).

Related API Elements

Reads a signed 16-bit integer from the stream.

The returned value is in the range -32768...32767.

Reads an unsigned byte from the stream.

The returned value is in the range 0...255.

Reads an unsigned 32-bit integer from the stream.

The returned value is in the range 0...4294967295.

Reads an unsigned 16-bit integer from the stream.

The returned value is in the range 0...65535.

Reads a UTF-8 string from the stream. The string is assumed to be prefixed with an unsigned short indicating the length in bytes.

Reads a sequence of length UTF-8 bytes from the stream, and returns a string.

Parameters

Dispatched when data has loaded successfully.

This event has the following properties:

Dispatched if a call to the URLStream.load() method attempts to access data over HTTP and Adobe AIR is able to detect and return the status code for the request.

If a URLStream object registers for an httpStatusEvent event, error responses are delivered as though they are content. So instead of dispatching an ioError event, the URLStream dispatches progress and complete events as the error data is loaded into the URLStream.

The HTTPStatusEvent.HTTP_RESPONSE_STATUS constant defines the value of the type property of a httpResponseStatus event object.

This event has the following properties:

Related API Elements

Dispatched if a call to URLStream.load() attempts to access data over HTTP, and Flash Player or Adobe AIR is able to detect and return the status code for the request. (Some browser environments may not be able to provide this information.) Note that the httpStatus (if any) will be sent before (and in addition to) any complete or error event.

This event has the following properties:

Related API Elements

Dispatched when an input/output error occurs that causes a load operation to fail.

This event has the following properties:

Related API Elements

Dispatched when a load operation starts.

This event has the following properties:

Related API Elements

Dispatched when data is received as the download operation progresses. Data that has been received can be read immediately using the methods of the URLStream class.

This event has the following properties:

Related API Elements

Dispatched if a call to URLStream.load() attempts to load data from a server outside the security sandbox.

This event has the following properties:

Related API Elements

To run the example, place a file named URLStreamExample.swf in the same directory as your SWF file.

package {
    import flash.display.Sprite;
    import flash.errors.*;
    import flash.events.*;
    import flash.net.URLRequest;
    import flash.net.URLStream;

    public class URLStreamExample extends Sprite {
        private static const ZLIB_CODE:String = "CWS";
        private var stream:URLStream;

        public function URLStreamExample() {
            stream = new URLStream();
            var request:URLRequest = new URLRequest("URLStreamExample.swf");
            configureListeners(stream);
            try {
                stream.load(request);
            } catch (error:Error) {
                trace("Unable to load requested URL.");
            }
        }

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

        private function parseHeader():void {
            trace("parseHeader");
            trace("isCompressed: " + isCompressed());
            trace("version: " + stream.readByte());
        }

        private function isCompressed():Boolean {
            return (stream.readUTFBytes(3) == ZLIB_CODE);
        }

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

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

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

        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);
        }
    }
}