SharedObject object

Availability

Flash Player 6.

Note: The SharedObject object is available only in the expert mode of the Actions panel.

Shared objects are quite powerful: they offer real-time data sharing between objects that are persistent on the local machine. You can think of local shared objects as "cookies."

You can use local shared objects to maintain local persistence. This is the simplest way to use a shared object. For example, you can call SharedObject.getLocal() to create a shared object, such as a calculator with memory, in the player. Because the shared object is locally persistent, Flash saves its data attributes on the user's machine when the movie ends. The next time the movie runs, the calculator contains the values it had when the movie ended. Alternatively, if you set the shared object's properties to null before the movie ends, the calculator opens without any prior values the next time the movie runs.

To create a local shared object, use the following syntax:

// Create a local shared object 
so = SharedObject.getLocal("foo");

Local disk space considerations

Local shared objects are always persistent on the client, up to available memory and disk space.

By default, Flash can save locally persistent remote shared objects up to 100K in size. When you try to save a larger object, the Flash Player displays the Local Storage dialog box, which lets the user allow or deny local storage for the domain that is requesting access. Make sure your Stage size is at least 215 x 138 pixels; this is the minimum size Flash requires to display the dialog box.

If the user clicks Allow, the object is saved and SharedObject.onStatus() is invoked with a code property of SharedObject.Flush.Success; if the user clicks Deny, the object is not saved and SharedObject.onStatus() is invoked with a code property of SharedObject.Flush.Failed.

The user can also specify permanent local storage settings for a particular domain by right-clicking (Windows) or Control-clicking (Macintosh) while a movie is playing, choosing Settings, and then opening the Local Storage panel.

The following list summarizes how the user's disk space choices interact with shared objects:

Additionally, if the user selects a value that is less than the amount of disk space currently being used for locally persistent data, the player warns the user that any locally saved shared objects will be deleted.

Note: There is no size limit in the Flash Player that runs from the authoring environment; the limit applies only to the stand-alone player.

Method summary for the SharedObject object

Method Description
SharedObject.clear() Purges all of the data from the shared object and deletes the shared object from the disk.
SharedObject.flush() Immediately writes a locally persistent shared object to a local file.
SharedObject.getLocal() Returns a reference to a locally persistent shared object that is available only to the current client.
SharedObject.getSize() Gets the current size of the shared object, in bytes.

Property summary for the SharedObject object

Property (read-only) Description
SharedObject.data The collection of attributes assigned to the data property of the object; these attributes can be shared and/or stored.

Event handler summary for the SharedObject object

Event handler Description
SharedObject.onStatus() Invoked every time an error, warning, or informational note is posted for a shared object.

Constructor for the SharedObject object

For information on creating local shared objects, see SharedObject.getLocal().

SharedObject information objects

The SharedObject object provides an onStatus event handler that uses an information object for providing information, status, or error messages. To respond to this event handler, you must create a function to process the information object, and you must know the format and contents of the information object returned.

In addition to the specific onStatus method, Flash also provides a "super" function called system.onStatus. If onStatus is invoked for a particular object and there is no function assigned to respond to it, Flash processes a function assigned to system.onStatus if it exists.

The following example illustrates how you can create functions to process information objects sent by the onStatus method.

//	 Create generic function
system.onStatus = function(genericError)
{
	// Your script would do something more meaningful here
	trace("An error has occurred. Please try again.");
};

By default, every information object has a code property containing a string that describes the result of the onStatus method, and a class property containing a string that is either "status", "warning", or "error". Some information objects have additional default properties, which provide more information about the reason onStatus was invoked, as displayed in the following table:

Code property Class property Meaning
SharedObject.Flush.Failed Error A SharedObject.flush() command that returned "pending" has failed (the user did not allot additional disk space for the shared object).
SharedObject.Flush.Success Status A SharedObject.flush() command that returned "pending" has been successfully completed (the user allotted additional disk space for the shared object).