class flash.net.SharedObject extends EventDispatcher
Available on all platforms
The SharedObject class is used to read and store limited amounts of data on
* a user's computer or on a server. Shared objects offer real-time data
* sharing between multiple client SWF files and objects that are persistent
* on the local computer or remote server. Local shared objects are similar to
* browser cookies and remote shared objects are similar to real-time data
* transfer devices. To use remote shared objects, you need Adobe Flash Media
* Server.
* Use shared objects to do the following:
-
*
- Maintain local persistence. This is the simplest way to use a
* shared object, and does not require Flash Media Server. For example, you
* can call
SharedObject.getLocal()
to create a shared object in * an application, such as a calculator with memory. When the user closes the * calculator, Flash Player saves the last value in a shared object on the * user's computer. The next time the calculator is run, it contains the * values it had previously. Alternatively, if you set the shared object's * properties tonull
before the calculator application is * closed, the next time the application runs, it opens without any values. * Another example of maintaining local persistence is tracking user * preferences or other data for a complex website, such as a record of which * articles a user read on a news site. Tracking this information allows you * to display articles that have already been read differently from new, * unread articles. Storing this information on the user's computer reduces * server load.
* - Store and share data on Flash Media Server. A shared object
* can store data on the server for other clients to retrieve. For example,
* call
SharedObject.getRemote()
to create a remote shared * object, such as a phone list, that is persistent on the server. Whenever a * client makes changes to the shared object, the revised data is available to * all clients currently connected to the object or who later connect to it. * If the object is also persistent locally, and a client changes data while * not connected to the server, the data is copied to the remote shared object * the next time the client connects to the object.
* - Share data in real time. A shared object can share data among * multiple clients in real time. For example, you can open a remote shared * object that stores a list of users connected to a chat room that is visible * to all clients connected to the object. When a user enters or leaves the * chat room, the object is updated and all clients that are connected to the * object see the revised list of chat room users. *
To create a local shared object, call
* SharedObject.getLocal()
. To create a remote shared object,
* call SharedObject.getRemote()
.
When an application closes, shared objects are flushed, or
* written to a disk. You can also call the flush()
method to
* explicitly write data to a disk.
Local disk space considerations. Local shared objects have some * limitations that are important to consider as you design your application. * Sometimes SWF files may not be allowed to write local shared objects, and * sometimes the data stored in local shared objects can be deleted without * your knowledge. Flash Player users can manage the disk space that is * available to individual domains or to all domains. When users decrease the * amount of disk space available, some local shared objects may be deleted. * Flash Player users also have privacy controls that can prevent third-party * domains(domains other than the domain in the current browser address bar) * from reading or writing local shared objects.
*Note: SWF files that are stored and run on a local computer, not * from a remote server, can always write third-party shared objects to disk. * For more information about third-party shared objects, see the <a * href="http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager03.html" * scope="external">Global Storage Settings panel in Flash Player * Help.
*It's a good idea to check for failures related to the amount of disk
* space and to user privacy controls. Perform these checks when you call
* getLocal()
and flush()
:
*
-
*
SharedObject.getLocal()
- Flash Player throws an * exception when a call to this method fails, such as when the user has * disabled third-party shared objects and the domain of your SWF file does * not match the domain in the browser address bar.
* SharedObject.flush()
- Flash Player throws an * exception when a call to this method fails. It returns *SharedObjectFlushStatus.FLUSHED
when it succeeds. It returns *SharedObjectFlushStatus.PENDING
when additional storage space * is needed. Flash Player prompts the user to allow an increase in storage * space for locally saved information. Thereafter, thenetStatus
* event is dispatched with an information object indicating whether the flush * failed or succeeded.
*
If your SWF file attempts to create or modify local shared objects, make
* sure that your SWF file is at least 215 pixels wide and at least 138 pixels
* high(the minimum dimensions for displaying the dialog box that prompts
* users to increase their local shared object storage limit). If your SWF
* file is smaller than these dimensions and an increase in the storage limit
* is required, SharedObject.flush()
fails, returning
* SharedObjectFlushedStatus.PENDING
and dispatching the
* netStatus
event.
Remote shared objects. With Flash Media Server, you can create * and use remote shared objects, that are shared in real-time by all clients * connected to your application. When one client changes a property of a * remote shared object, the property is changed for all connected clients. * You can use remote shared objects to synchronize clients, for example, * users in a multi-player game.
* Each remote shared object has a data
property which is an
* Object with properties that store data. Call setProperty()
to
* change an property of the data object. The server updates the properties,
* dispatches a sync
event, and sends the properties back to the
* connected clients.
You can choose to make remote shared objects persistent on the client, * the server, or both. By default, Flash Player saves locally persistent * remote shared objects up to 100K in size. When you try to save a larger * object, Flash Player displays the Local Storage dialog box, which lets the * user allow or deny local storage for the shared object. Make sure your * Stage size is at least 215 by 138 pixels; this is the minimum size Flash * requires to display the dialog box.
* If the user selects Allow, the server saves the shared object and
* dispatches a netStatus
event with a code
property
* of SharedObject.Flush.Success
. If the user select Deny, the
* server does not save the shared object and dispatches a
* netStatus
event with a code
property of
* SharedObject.Flush.Failed
.
netStatus
* event contains an info
property, which is an
* information object that contains specific information
* about the event, such as whether a connection attempt
* succeeded or whether the shared object was successfully
* written to the local disk.
* @event sync Dispatched when a remote shared object has been updated
* by the server.Class Fields
static var defaultObjectEncoding:UInt
The default object encoding(AMF version) for all local shared objects
* created in the SWF file. When local shared objects are written to disk,
* the For more information about object encoding, including the difference
* between encoding in local and remote shared objects, see the description
* of the SharedObject.defaultObjectEncoding
property indicates
* which Action Message Format version should be used: the ActionScript 3.0
* format(AMF3) or the ActionScript 1.0 or 2.0 format(AMF0).
* objectEncoding
property.
The default value of SharedObject.defaultObjectEncoding
is
* set to use the ActionScript 3.0 format, AMF3. If you need to write local
* shared objects that ActionScript 2.0 or 1.0 SWF files can read, set
* SharedObject.defaultObjectEncoding
to use the ActionScript
* 1.0 or ActionScript 2.0 format,
* flash.net.ObjectEncoding.AMF0
, at the beginning of your
* script, before you create any local shared objects. All local shared
* objects created thereafter will use AMF0 encoding and can interact with
* older content. You cannot change the objectEncoding
value of
* existing local shared objects by setting
* SharedObject.defaultObjectEncoding
after the local shared
* objects have been created.
To set the object encoding on a per-object basis, rather than for all
* shared objects created by the SWF file, set the
* objectEncoding
property of the local shared object
* instead.
static function getLocal(name:String, ?localPath:String, ?secure:Bool):SharedObject
Returns a reference to a locally persistent shared object that is only
* available to the current client. If the shared object does not already
* exist, this method creates one. If any values passed to
* The following code shows how you assign the returned shared object
* reference to a variable:getLocal()
are invalid or if the call fails, Flash Player
* throws an exception.
*
var so:SharedObject =
* SharedObject.getLocal("savedData");
Note: If the user has chosen to never allow local storage for
* this domain, the object is not saved locally, even if a value for
* localPath
is specified. The exception to this rule is local
* content. Local content can always write shared objects from third-party
* domains(domains other than the domain in the current browser address bar)
* to disk, even if writing of third-party shared objects to disk is
* disallowed.
To avoid name conflicts, Flash looks at the location of the SWF file
* creating the shared object. For example, if a SWF file at
* www.myCompany.com/apps/stockwatcher.swf creates a shared object named
* portfolio
, that shared object does not conflict with another
* object named portfolio
that was created by a SWF file at
* www.yourCompany.com/photoshoot.swf because the SWF files originate from
* different directories.
Although the localPath
parameter is optional, you should
* give some thought to its use, especially if other SWF files need to access
* the shared object. If the data in the shared object is specific to one SWF
* file that will not be moved to another location, then use of the default
* value makes sense. If other SWF files need access to the shared object, or
* if the SWF file that creates the shared object will later be moved, then
* the value of this parameter affects how accessible the shared object will
* be. For example, if you create a shared object with localPath
* set to the default value of the full path to the SWF file, no other SWF
* file can access that shared object. If you later move the original SWF
* file to another location, not even that SWF file can access the data
* already stored in the shared object.
To avoid inadvertently restricting access to a shared object, use the
* localpath
parameter. The most permissive approach is to set
* localPath
to /
(slash), which makes the shared
* object available to all SWF files in the domain, but increases the
* likelihood of name conflicts with other shared objects in the domain. A
* more restrictive approach is to append localPath
with folder
* names that are in the full path to the SWF file. For example, for a
* portfolio
shared object created by the SWF file at
* www.myCompany.com/apps/stockwatcher.swf, you could set the
* localPath
parameter to /
, /apps
, or
* /apps/stockwatcher.swf
. You must determine which approach
* provides optimal flexibility for your application.
When using this method, consider the following security model: *
-
*
- You cannot access shared objects across sandbox boundaries. *
- Users can restrict shared object access by using the Flash Player * Settings dialog box or the Settings Manager. By default, an application * can create shared objects of up 100 KB of data per domain. Administrators * and users can also place restrictions on the ability to write to the file * system. *
Suppose you publish SWF file content to be played back as local files * (either locally installed SWF files or EXE files), and you need to access * a specific shared object from more than one local SWF file. In this * situation, be aware that for local files, two different locations might be * used to store shared objects. The domain that is used depends on the * security permissions granted to the local file that created the shared * object. Local files can have three different levels of permissions: *
-
*
- Access to the local filesystem only. *
- Access to the network only. *
- Access to both the network and the local filesystem. *
Local files with access to the local filesystem(level 1 or 3) store * their shared objects in one location. Local files without access to the * local filesystem(level 2) store their shared objects in another * location.
*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.
For more information, see the Flash Player Developer Center Topic: <a * href="http://www.adobe.com/go/devnetsecurityen" * scope="external">Security.
* *name | The name of the object. The name can include forward
* slashes( ~ % & \ * ; : " ' , < > ? #* |
localPath | The full or partial path to the SWF file that created the shared object, and that determines where the shared object will be stored locally. If you do not specify this parameter, the full path is used. |
secure | Determines whether access to this shared object is * restricted to SWF files that are delivered over an HTTPS * connection. If your SWF file is delivered over HTTPS, * this parameter's value has the following effects: *
If your SWF file is delivered over a non-HTTPS
* connection and you try to set this parameter to
* The following diagram shows the use of the
* |
returns | A reference to a shared object that is persistent locally and is
available only to the current client. If Flash Player can't create
or find the shared object(for example, if |
static function getRemote(name:String, ?remotePath:String, ?persistence:Dynamic, ?secure:Bool):SharedObject
Returns a reference to a shared object on Flash Media Server that multiple
* clients can access. If the remote shared object does not already exist,
* this method creates one.
* To create a remote shared object, call getRemote()
the
* call connect()
to connect the remote shared object to the
* server, as in the following:
To confirm that the local and remote copies of the shared object are
* synchronized, listen for and handle the sync
event. All
* clients that want to share this object must pass the same values for the
* name
and remotePath
parameters.
To create a shared object that is available only to the current client,
* use SharedObject.getLocal()
.
name | The name of the remote shared object. The name can * include forward slashes(/); for example, * work/addresses is a legal name. Spaces are not allowed * in a shared object name, nor are the following * characters: ~ % & \ ; : " ' * , > ? ? #* |
remotePath | The URI of the server on which the shared object will
* be stored. This URI must be identical to the URI of the
* NetConnection object passed to the
* |
persistence | Specifies whether the attributes of the shared object's
data property are persistent locally, remotely, or
both. This parameter can also specify where the shared
object will be stored locally. Acceptable values are as
follows:
false specifies that the
shared object is not persistent on the client or
server.true specifies that the
Note: If the user has chosen to never allow local storage for this domain, the object will not be saved locally, even if a local path is specified for persistence. For more information, see the class description. * |
secure | Determines whether access to this shared object is
* restricted to SWF files that are delivered over an
* HTTPS connection. For more information, see the
* description of the |
returns | A reference to an object that can be shared across multiple clients. |
Instance Fields
Indicates the object on which callback methods are invoked. The default
* object is this
. You can set the client property to another
* object, and callback methods will be invoked on that other object.
*
*
The collection of attributes assigned to the data
property of
* the object; these attributes can be shared and stored. Each attribute can
* be an object of any ActionScript or JavaScript type - Array, Number,
* Boolean, ByteArray, XML, and so on. For example, the following lines
* assign values to various aspects of a shared object:
*
*
For remote shared objects used with a server, all attributes of the
* data
property are available to all clients connected to the
* shared object, and all attributes are saved if the object is persistent.
* If one client changes the value of an attribute, all clients now see the
* new value.
Specifies the number of times per second that a client's changes to a
* shared object are sent to the server.
* Use this method when you want to control the amount of traffic between
* the client and the server. For example, if the connection between the
* client and server is relatively slow, you may want to set fps
* to a relatively low value. Conversely, if the client is connected to a
* multiuser application in which timing is important, you may want to set
* fps
to a relatively high value.
Setting fps
will trigger a sync
event and
* update all changes to the server. If you only want to update the server
* manually, set fps
to 0.
Changes are not sent to the server until the sync
event
* has been dispatched. That is, if the response time from the server is
* slow, updates may be sent to the server less frequently than the value
* specified in this property.
var objectEncoding:UInt
The object encoding(AMF version) for this shared object. When a local
* shared object is written to disk, the Object encoding is handled differently depending if the shared object
* is local or remote.objectEncoding
property
* indicates which Action Message Format version should be used: the
* ActionScript 3.0 format(AMF3) or the ActionScript 1.0 or 2.0 format
* (AMF0).
*
-
*
- Local shared objects. You can get or set the value of the
*
objectEncoding
property for local shared objects. The value * ofobjectEncoding
affects what formatting is used for * writing this local shared object. If this local shared object must * be readable by ActionScript 2.0 or 1.0 SWF files, set *objectEncoding
toObjectEncoding.AMF0
. Even if * object encoding is set to write AMF3, Flash Player can still read AMF0 * local shared objects. That is, if you use the default value of this * property,ObjectEncoding.AMF3
, your SWF file can still read * shared objects created by ActionScript 2.0 or 1.0 SWF files.
* - Remote shared objects. When connected to the server, a remote
* shared object inherits its
objectEncoding
setting from the * associated NetConnection instance(the instance used to connect to the * remote shared object). When not connected to the server, a remote shared * object inherits thedefaultObjectEncoding
setting from the * associated NetConnection instance. Because the value of a remote shared * object'sobjectEncoding
property is determined by the * NetConnection instance, this property is read-only for remote shared * objects.
*
The current size of the shared object, in bytes. * *
Flash calculates the size of a shared object by stepping through all of * its data properties; the more data properties the object has, the longer * it takes to estimate its size. Estimating object size can take significant * processing time, so you may want to avoid using this method unless you * have a specific need for it.
For local shared objects, purges all of the data and deletes the shared * object from the disk. The reference to the shared object is still active, * but its data properties are deleted. * *
For remote shared objects used with Flash Media Server,
* clear()
disconnects the object and purges all of the data. If
* the shared object is locally persistent, this method also deletes the
* shared object from the disk. The reference to the shared object is still
* active, but its data properties are deleted.
Closes the connection between a remote shared object and the server. If a * remote shared object is locally persistent, the user can make changes to * the local copy of the object after this method is called. Any changes made * to the local object are sent to the server the next time the user connects * to the remote shared object.
function connect(myConnection:NetConnection, ?params:String):Void
Connects to a remote shared object on a server through a specified
* NetConnection object. Use this method after calling
* Before attempting to work with a remote shared object, first check for
* any errors using a getRemote()
. When a connection is successful, the
* sync
event is dispatched.
* try..catch..finally
statement. Then,
* listen for and handle the sync
event before you make changes
* to the shared object. Any changes made locally - before the
* sync
event is dispatched - might be lost.
Call the connect()
method to connect to a remote shared
* object, for example:
myConnection | A NetConnection object that uses the Real-Time Messaging Protocol(RTMP), such as a NetConnection object used to communicate with Flash Media Server. * |
params | A string defining a message to pass to the remote * shared object on the server. Cannot be used with Flash * Media Server. * |
function flush(?minDiskSpace:Int):String
Immediately writes a locally persistent shared object to a local file. If
* you don't use this method, Flash Player writes the shared object to a file
* when the shared object session ends - that is, when the SWF file is
* closed, when the shared object is garbage-collected because it no longer
* has any references to it, or when you call
* If this method returns SharedObject.clear()
or SharedObject.close()
.
* SharedObjectFlushStatus.PENDING
,
* Flash Player displays a dialog box asking the user to increase the amount
* of disk space available to objects from this domain. To allow space for
* the shared object to grow when it is saved in the future, which avoids
* return values of PENDING
, pass a value for
* minDiskSpace
. When Flash Player tries to write the file, it
* looks for the number of bytes passed to minDiskSpace
, instead
* of looking for enough space to save the shared object at its current size.
*
For example, if you expect a shared object to grow to a maximum size of
* 500 bytes, even though it might start out much smaller, pass 500 for
* minDiskSpace
. If Flash asks the user to allot disk space for
* the shared object, it asks for 500 bytes. After the user allots the
* requested amount of space, Flash won't have to ask for more space on
* future attempts to flush the object(as long as its size doesn't exceed
* 500 bytes).
After the user responds to the dialog box, this method is called again.
* A netStatus
event is dispatched with a code
* property of SharedObject.Flush.Success
or
* SharedObject.Flush.Failed
.
minDiskSpace | The minimum disk space, in bytes, that must be allotted for this object. |
returns | Either of the following values:
SharedObjectFlushStatus.PENDING : The user has
permitted local information storage for objects from this domain,
but the amount of space allotted is not sufficient to store the
object. Flash Player prompts the user to allow more space. To
allow space for the shared object to grow when it is saved, thus
avoiding a SharedObjectFlushStatus.PENDING return
value, pass a value for minDiskSpace . SharedObjectFlushStatus.FLUSHED : The shared
|
function send(?p1:Dynamic, ?p2:Dynamic, ?p3:Dynamic, ?p4:Dynamic, ?p5:Dynamic):Void
Broadcasts a message to all clients connected to a remote shared object, * including the client that sent the message. To process and respond to the * message, create a callback function attached to the shared object.
function setDirty(propertyName:String):Void
Indicates to the server that the value of a property in the shared object
* has changed. This method marks properties as dirty, which means
* changed.
* Call the SharedObject.setProperty()
to create properties
* for a shared object.
The SharedObject.setProperty()
method implements
* setDirty()
. In most cases, such as when the value of a
* property is a primitive type like String or Number, you can call
* setProperty()
instead of calling setDirty()
.
* However, when the value of a property is an object that contains its own
* properties, call setDirty()
to indicate when a value within
* the object has changed.
propertyName | The name of the property that has changed. |
function setProperty(propertyName:String, ?value:Object):Void
Updates the value of a property in a shared object and indicates to the
* server that the value of the property has changed. The
* For more information about remote shared objects see the <a
* href="http://www.adobe.com/go/learnfmsdocs_en"> Flash Media Server
* documentation.setProperty()
method explicitly marks properties as changed,
* or dirty.
*
Note: The SharedObject.setProperty()
method
* implements the setDirty()
method. In most cases, such as when
* the value of a property is a primitive type like String or Number, you
* would use setProperty()
instead of setDirty
.
* However, when the value of a property is an object that contains its own
* properties, use setDirty()
to indicate when a value within
* the object has changed. In general, it is a good idea to call
* setProperty()
rather than setDirty()
, because
* setProperty()
updates a property value only when that value
* has changed, whereas setDirty()
forces synchronization on all
* subscribed clients.
propertyName | The name of the property in the shared object. * |
value | The value of the property(an ActionScript object), or
* |