Adobe® Flex® 4 Language Reference
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flash.desktop 
NativeProcess 
Packageflash.desktop
Classpublic class NativeProcess
InheritanceNativeProcess Inheritance EventDispatcher Inheritance Object

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

The NativeProcess class provides command line integration and general launching capabilities. The NativeProcess class lets an AIR application execute native processes on the host operating system. The AIR applcation can monitor the standard input (stdin) and standard output (stdout) stream of the process as well as the process's standard error (stderr) stream.

The NativeProcess class and its capabilities are only available to AIR applications installed with a native installer (extended desktop profile applications). When debugging, you can pass the -profile extendedDesktop argument to ADL to enable the NativeProcess functionality. At runtime, you can check the NativeProcess.isSupported property to to determine whether native process communication is supported.

AIR applications installed with a native installer (extended desktop profile applications) can also use the File.openWithDefaultApplication to open an application. However, the NativeProcess class provides direct access to the standard input, standard output, and standard error pipes.

View the examples



Public Properties
 PropertyDefined By
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
  AIR-only isSupported : Boolean
[static] [read-only] Indicates if running native processes is supported in the current profile.
NativeProcess
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
Object
  AIR-only running : Boolean
[read-only] Indicates if this native process is currently running.
NativeProcess
  AIR-only standardError : IDataInput
[read-only] Provides access to the standard error output from this native process.
NativeProcess
  AIR-only standardInput : IDataOutput
[read-only] Provides access to the standard input of this native process.
NativeProcess
  AIR-only standardOutput : IDataInput
[read-only] Provides access to the standard output pipe of this native process.
NativeProcess
Public Methods
 MethodDefined By
  
Constructs an uninitialized NativeProcess object.
NativeProcess
 Inherited
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
  
Closes the input stream on this process.
NativeProcess
 Inherited
Dispatches an event into the event flow.
EventDispatcher
  
AIR-only exit(force:Boolean = false):void
Attempts to exit the native process.
NativeProcess
 Inherited
Checks whether the EventDispatcher object has any listeners registered for a specific type of event.
EventDispatcher
 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
removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void
Removes a listener from the EventDispatcher object.
EventDispatcher
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
  
Starts the native process identified by the start up info specified.
NativeProcess
 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
 Inherited
Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.
EventDispatcher
Events
 Event Summary Defined By
 Inherited[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.EventDispatcher
 Inherited[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.EventDispatcher
  Signals the native process has exited.NativeProcess
  Signals that the NativeProcess has closed its error stream.NativeProcess
  Signals that the native process has data available to read on the standard error (stderror) stream.NativeProcess
  Signals that reading from the standard error (stderror) stream has failed.NativeProcess
  Signals that the NativeProcess object has closed its input stream by calling the closeInput() method.NativeProcess
  Signals that writing to the standard input (stdin) stream has failed.NativeProcess
  Signals that the NativeProcess has written data to the input stream for the child process.NativeProcess
  Signals that the NativeProcess has closed its output stream.NativeProcess
  Signals that the native process has data available to read on the output stream.NativeProcess
  Signals that reading from the stdout stream has failed.NativeProcess
Property Detail
AIR-only 

isSupported

property
isSupported:Boolean  [read-only]

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Indicates if running native processes is supported in the current profile. This property returns true only when running in the extendedDesktop profile.



Implementation
    public static function get isSupported():Boolean
AIR-only 

running

property 
running:Boolean  [read-only]

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Indicates if this native process is currently running. The process is running if you have called the start() method and the NativeProcess object has not yet dispatched an exit event. A NativeProcess instance corresponds to a single process on the underlying operating system. This property remains true as long as the underlying operating system process is executing (while the native process is starting and until the process returns an exit code to the operating system.)



Implementation
    public function get running():Boolean
AIR-only 

standardError

property 
standardError:IDataInput  [read-only]

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Provides access to the standard error output from this native process. As data becomes available on this pipe, the NativeProcess object dispatches a ProgressEvent object. If you attempt to read data from this stream when no data is available, the NativeProcess object throw an EOFError exception.

The type is IDataInput because data is input from the perspective of the current process, even though it is an output stream of the child process.



Implementation
    public function get standardError():IDataInput

Throws
EOFError — if no data is present and a read operation is attempted.

See also

AIR-only 

standardInput

property 
standardInput:IDataOutput  [read-only]

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Provides access to the standard input of this native process. Use this pipe to send data to this process. Each time data is written to the input property that data is written to the native process's input pipe as soon as possible.

The type is IDataOutput because data is output from the perspective of the current process, even though it is an input stream of the child process.



Implementation
    public function get standardInput():IDataOutput

Throws
IllegalOperationError — when writing to this value when running returns false or when attempting to write data to a closed input stream.

See also

AIR-only 

standardOutput

property 
standardOutput:IDataInput  [read-only]

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Provides access to the standard output pipe of this native process. Use this pipe to read data from the native process's standard output. When data is present on this pipe, the NativeProcess object dispatches a ProgressEvent. If you attempt to read data from this stream when no data is available, the NativeProcess object throws an EOFError.

The type is IDataInput because data is input from the perspective of the current process even though it is an output stream of the child process.



Implementation
    public function get standardOutput():IDataInput

Throws
EOFError — if no data is present and a read operation is attempted.

See also

Constructor Detail
AIR-only 

NativeProcess

()Constructor
public function NativeProcess()

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Constructs an uninitialized NativeProcess object. Call the start() method to start the process.

See also

Method Detail

AIR-only closeInput

()method
public function closeInput():void

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Closes the input stream on this process. Some command line applications wait until the input stream is closed to start some operations. Once the stream is closed it cannot be re-opened until the process exits and is started again.


Events
ioErrorStandardInput:IOErrorEvent — There is a problem closing the input stream to the process
 
standardInputClose:Event — The input stream has been closed.

AIR-only exit

()method 
public function exit(force:Boolean = false):void

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Attempts to exit the native process.

Parameters

force:Boolean (default = false) — Whether the application should attempt to forcibly exit the native process, if necessary.

If the force parameter is set to false, this method attempts to gracefully exit the native process. This method "asks" the native process to exit. This request may be ignored by the native process, and as a result this method is not guaranteed to actually cause the native process to exit. The NativeProcess object only dispatches a NativeProcessExitEvent event if the native process exits.

If the force parameter is set to true, this method attempts to forcibly exit the native process. Calling this method with the force parameter is set to true should be a last resort. Calling this method with the force parameter is set to true may have adverse affects on the state of system resources associated with the native process. For example, opened files may be left in an inconsistent state. The runtime will make its best effort to try to force the native process to exit. However, it is not guaranteed that the native process will exit. The NativeProcess object only dispatches a NativeProcessExitEvent event if the native process exits.

If the NativeProcess does successfully exit, it dispatches a NativeProcessExitEvent event.

AIR-only start

()method 
public function start(info:NativeProcessStartupInfo):void

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Starts the native process identified by the start up info specified. Once the process starts, all of the input and output streams will be opened. This method returns immediately after the request to start the specified process has been made to the operating system. The NativeProcess object throws an IllegalOperationError exception if the process is currently running. The process is running if the running property of the NativeProcess object returns true. If the operating system is unable to start the process, an Error is thrown.

A NativeProcess instance corresponds to a single process on the underlying operating system. If you want to execute more than one instance of the same operating system process concurrently, you can create one NativeProcess instance per child process.

You can call this method whenever the running property of the NativeProcess object returns false. This means that the NativeProcess object can be reused. In other words you can construct a NativeProcess instance, call the start() method, wait for the exit event, and then call the start() method again. You may use a different NativeProcessStartupInfo object as the info parameter value in the subsequent call to the start() method.

The NativeProcess class and its capabilities are only available to AIR applications installed with a native installer. When debugging, you can pass the -profile extendedDesktop argument to ADL to enable the NativeProcess functionality. Check the NativeProcess.isSupported property to to determine whether native process communication is supported.

Important security considerations:

The native process API can run any executable on the user's system. Take extreme care when constructing and executing commands. If any part of a command to be executed originates from an external source, carefully validate that the command is safe to execute. Likewise, your AIR application should validate data passed to a running process.

However, validating input can be difficult. To avoid such difficulties, it is best to write a native application (such as an EXE file on Windows) that has specific APIs. These APIs should process only those commands specifically required by the AIR application. For example, the native application may accept only a limited set of instructions via the standard input stream.

AIR on Windows does not allow you to run .bat files directly. Windows .bat files are executed by the command interpreter application (cmd.exe). When you invoke a .bat file, this command application can interpret arguments passed to the command as additional applications to launch. A malicious injection of extra characters in the argument string could cause cmd.exe to execute a harmful or insecure application. For example, without proper data validation, your AIR application may call myBat.bat myArguments c:/evil.exe. The command application would launch the evil.exe application in addition to running your batch file.

If you call the start() method with a .bat file, the NativeProcess object throws an exception. The message property of the Error object contains the string "Error #3219: The NativeProcess could not be started."

Parameters

info:NativeProcessStartupInfo — NativeProcessStartupInfo Defines information about how to start the native process.


Throws
IllegalOperationError — if the NativeProcess is currently running.
 
ArgumentError — if the nativePath property of the NativeProcessStartupInfo does not exist.
 
Error — if the NativeProcess did not start successfully.

See also

Event Detail
AIR-only 

exit

Event
Event Object Type: flash.events.NativeProcessExitEvent
property NativeProcessExitEvent.type = flash.events.NativeProcessExitEvent

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals the native process has exited. The exitCode property contains the value the process returns to the host operating system on exit. If the AIR application terminates the process by calling the exit() method of the NativeProcess object, the exitCode property is set to NaN.

AIR-only 

standardErrorClose

Event  
Event Object Type: flash.events.Event
property Event.type = flash.events.Event

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that the NativeProcess has closed its error stream.

AIR-only 

standardErrorData

Event  
Event Object Type: flash.events.ProgressEvent
property ProgressEvent.type = flash.events.ProgressEvent

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that the native process has data available to read on the standard error (stderror) stream. The NativeProcess object dispatches this event when the child process flushes its standard error stream or when the internal buffer used to communicate between the processes is full. Do not write code that depend on the size of this internal buffer; it varies between versions and operating systems.

AIR-only 

standardErrorIoError

Event  
Event Object Type: flash.events.IOErrorEvent
property IOErrorEvent.type = flash.events.IOErrorEvent

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that reading from the standard error (stderror) stream has failed. The NativeProcess object can dispatch this event when the runtime cannot read data from the native process's standard error pipe.

AIR-only 

standardInputClose

Event  
Event Object Type: flash.events.Event
property Event.type = flash.events.Event

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that the NativeProcess object has closed its input stream by calling the closeInput() method. The NativeProcess object does not dispatch this event when the actual native process itself closes the input stream.

AIR-only 

standardInputIoError

Event  
Event Object Type: flash.events.IOErrorEvent
property IOErrorEvent.type = flash.events.IOErrorEvent

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that writing to the standard input (stdin) stream has failed. The NativeProcess object dispatches this event when the closeInput() method fails or when the runtime cannot write data to the native process's standard input pipe.

AIR-only 

standardInputProgress

Event  
Event Object Type: flash.events.ProgressEvent
property ProgressEvent.type = flash.events.ProgressEvent

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that the NativeProcess has written data to the input stream for the child process. The NativeProcess object dispatches this event when data is written to the stream. This event does not indicate whether or not the child process has read any of the data.

AIR-only 

standardOutputClose

Event  
Event Object Type: flash.events.Event
property Event.type = flash.events.Event

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that the NativeProcess has closed its output stream.

AIR-only 

standardOutputData

Event  
Event Object Type: flash.events.ProgressEvent
property ProgressEvent.type = flash.events.ProgressEvent

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that the native process has data available to read on the output stream. The NativeProcess object dispatches this event when the child process flushes its stdout stream or when the internal buffer used to communicate between the processes is full. Do not write code that depend on the size of this internal buffer; it varies between versions and operating systems.

AIR-only 

standardOutputIoError

Event  
Event Object Type: flash.events.IOErrorEvent
property IOErrorEvent.type = flash.events.IOErrorEvent

Language Version: ActionScript 3.0
Runtime Versions: AIR 2

Signals that reading from the stdout stream has failed. The NativeProcess object can dispatch this event when the runtime cannot read data from the native process's standard output pipe.

NativeProcessExample.as

The following example checks to see if native process communication is supported on the machine. If it is, the application sets up event listeners for the native process and launches the test.py file in the main application directory). :
package
{
    import flash.display.Sprite;
    import flash.desktop.NativeProcess;
    import flash.desktop.NativeProcessStartupInfo;
    import flash.events.Event;
    import flash.events.ProgressEvent;
    import flash.events.IOErrorEvent;
    import flash.events.NativeProcessExitEvent;
    import flash.filesystem.File;
    
    public class NativeProcessExample extends Sprite
    {
        public var process:NativeProcess;

        public function NativeProcessExample()
        {
            if(NativeProcess.isSupported)
            {
                setupAndLaunch();
            }
            else
            {
                trace("NativeProcess not supported.");
            }
        }
        
        public function setupAndLaunch():void
        {     
            var nativeProcessStartupInfo:NativeProcessStartupInfo = new NativeProcessStartupInfo();
            var file:File = File.applicationDirectory.resolvePath("test.py");
            nativeProcessStartupInfo.executable = file;

            var processArgs:Vector.<String> = new Vector.<String>();
            processArgs[0] = "foo";
            nativeProcessStartupInfo.arguments = processArgs;

            process = new NativeProcess();
            process.start(nativeProcessStartupInfo);
            process.addEventListener(ProgressEvent.STANDARD_OUTPUT_DATA, onOutputData);
            process.addEventListener(ProgressEvent.STANDARD_ERROR_DATA, onErrorData);
            process.addEventListener(NativeProcessExitEvent.EXIT, onExit);
            process.addEventListener(IOErrorEvent.STANDARD_OUTPUT_IO_ERROR, onIOError);
            process.addEventListener(IOErrorEvent.STANDARD_ERROR_IO_ERROR, onIOError);

        public function onOutputData(event:ProgressEvent):void
        {
            trace("Got: ", process.standardOutput.readUTFBytes(process.standardOutput.bytesAvailable)); 
        }
        
        public function onErrorData(event:ProgressEvent):void
        {
            trace("ERROR -", process.standardError.readUTFBytes(process.standardError.bytesAvailable)); 
        }
        
        public function onExit(event:NativeProcessExitEvent):void
        {
            trace("Process exited with ", event.exitCode);
        }
        
        public function onIOError(event:IOErrorEvent):void
        {
             trace(event.toString());
        }
    }
}
Add the following Python script to a file named test.py in your application directory (and the ensure that Python is installed):
 #!/usr/bin/python
 # ------------------------------------------------------------------------------
 # Sample Python script
 # ------------------------------------------------------------------------------
 
 import sys
 
 for word in sys.argv: #echo the command line arguments
     print word
 
 print "HI FROM PYTHON"
 print "Enter user name" 
 line = sys.stdin.readline()
 
 sys.stdout.write("hello," + line)