About application instances

Applications are run by creating application instances. When a client connects to an application, the client is actually connected to an application instance. For example, a client connects to an application named chat_app, as the following example shows:

nc.connect("rtmp://myDomain.com/chat_app");

In this example, the client is actually connected to the default instance of the application, named _defInst_, because no instance is specified.

Clients can also connect to specific application instances that the instanceName value in the NetConnection.connect command defines, as the following example shows:

nc.connect("rtmp://myDomain.com/chat_app/instance1");

In this example, the client is connected to the application instance named instance1.

You might want to use application instances for specific purposes. For example, you may want to give different groups of people access to the same application without having the groups interact with each other, such as in a chat application with "rooms" for different topics. To do this, you can have multiple instances of the chat application at the same time, as follows:

my_nc.connect("rtmp://myServer.myDomain.com/chatApp/room_01")
my_nc.connect("rtmp://myServer.myDomain.com/chatApp/room_02")

Each application instance is uniquely named. Unlike the parent application, an instance does not require that its own directory be defined on the server. However, application resources, such as streams and shared objects, are independent for each instance and are stored in their own directories under the streams and sharedObjects storage directories configured for the application.

Another reason to use application instances is to avoid collision of recorded streams or shared objects that are created by the application. In the preceding example, for instance, any streams or shared objects that room_01 creates are distinct from those that room_02 creates, and the reverse, even though both instances are running the same application, chat_App.

For example, although the support application in the following code creates two shared objects named CustomerInfo, each instance of the support application has access only to its own CustomerInfo object. Also, the data in CustomerInfo used by session1 is different from the data in CustomerInfo used by session2, as the following example shows:

// One instance of application "support"
first_nc = new NetConnection();
first_nc.connect("myserver.mydomain.com/support/session1");
first_so = SharedObject.getRemote("CustomerInfo", first_nc.URI, false);
first_so.connect(first_nc.URI);

// Another instance of application "support"
second_nc = new NetConnection();
second_nc.connect("myserver.mydomain.com/support/session2");
second_so = SharedObject.getRemote("CustomerInfo", second_nc.URI, false);
second_so.connect(second_nc.URI);

Instance name room_01 is frequently used, but you can use any string for an instance name that makes sense in your application.

You can configure several settings related to application instances. In the Application.xml file, you can configure the maximum idle time before the server unloads an instance. In the Vhost.xml file, you can configure the number of clients that can connect to the virtual host hosting an application and the number of instances that the virtual host can load.

For more information on using instance names, see the NetStream.publish() entry in the Client-Side ActionScript Language Reference for Flash Media Server 2.

For information on making remote shared objects available to multiple applications, see the SharedObject.getRemote() entry in the Client-Side ActionScript Language Reference for Flash Media Server 2.

Comments

No screen name said on May 11, 2006 at 2:40 PM :

You have to manually create an application folder under the location defined in C:\Program Files\Macromedia\Flash Media Server 2\conf\fms.ini , right? At least that is what I just did.

slashbodyslashhtml said on Oct 15, 2007 at 1:24 PM :

If you're streaming FLVs you need to create the following folders in Linux.
Path-to-server\applications\appname\streams\_definst_\yourfile.flv

And when you call the file from the FLV component parameter in Flash your rtmp url is:
rtmp://flashserver.company.com/application_name/_definst_/yourfile.flv
NOTE: the folder streams is not present in the url.