Name
connection (LzConnection) (as2) — A connection manager to create a persistent connection and an authenticated session.
Synopsis
- LZX: connection
- JavaScript: LzConnection
- Type: Class
- Access: public
- Runtimes: as2
- Topic: LFC.Data
- Declared in: WEB-INF/lps/lfc/data/platform/swf/LzConnection.lzs
Description
The connection tag instantiates a connection
manager object that handles asynchronous messages sent from the OpenLaszlo
Server. Use the the LzConnection.connect method to establish a
persistent connection and disconnect to close it down.
Example 3. Connection example
<canvas debug="true" height="200">
<debug y="60"/>
<connection authenticator="anonymous">
<handler name="onconnect">
Debug.write('connected');
</handler>
<handler name="ondisconnect">
Debug.write('client disconnected');
</handler>
</connection>
<view>
<simplelayout axis="x" spacing="5"/>
<button>connect
<handler name="onclick">
canvas.connection.connect();
</handler>
</button>
<button>disconnect
<handler name="onclick">
canvas.connection.disconnect();
</handler>
</button>
</view>
</canvas>
You can optionally use the clientDisconnect method to close
down only the client-side connection. The server will drop its end of the
connection when it next becomes aware that the connection has been dropped.
The previous example declares connection with
authenticator="anonymous", which tells the connection
manager that no authentication should be used to handle the persistent
connection. Normally, the connection manager will tell the OpenLaszlo Server to
verify that your connection is authenticated with a back-end
authentication server before allowing the persistent connection, which
is done through a session cookie. The default authentication server it
uses is the AuthenticationServlet bundled with the OpenLaszlo Server. The set of usernames that server uses is located in
lps/config/lzusers.xml. To session and unsession your
application, use the connection's login and
logout methods.
The next example demonstrates how to login with the username
adam. Note that you will be allowed to connect only after
logging in.
Example 4. Session Example
<canvas debug="true" height="200">
<debug y="60"/>
<connection>
<handler name="onconnect">
Debug.write('connected as ' + connection.getUsername());
</handler>
<handler name="ondisconnect">
Debug.write('client disconnected');
</handler>
</connection>
<datapointer xpath="connection:loginDset:/login[1]/authentication[1]/response[1]/status[1]">
<handler name="ondata">
var statusMessage = this.xpathQuery('@msg');
Debug.write('login: ' + statusMessage);
</handler>
<handler name="onerror">
Debug.write('login resulted in error');
</handler>
<handler name="ontimeout">
Debug.write('login timed out');
</handler>
</datapointer>
<datapointer xpath="connection:logoutDset:/logout[1]/authentication[1]/response[1]/status[1]">
<handler name="ondata">
var statusMessage = this.xpathQuery('@msg');
Debug.write('logout: ' + statusMessage);
</handler>
<handler name="onerror">
Debug.write('logout resulted in error');
</handler>
<handler name="ontimeout">
Debug.write('logout timed out');
</handler>
</datapointer>
<view>
<simplelayout axis="x" spacing="5"/>
<button>login
<handler name="onclick">
canvas.connection.login('adam', 'adam');
</handler>
</button>
<button>logout
<handler name="onclick">
canvas.connection.logout();
</handler>
</button>
<simplelayout axis="x" spacing="5"/>
<button>connect
<handler name="onclick">
canvas.connection.connect();
</handler>
</button>
<button>disconnect
<handler name="onclick">
canvas.connection.disconnect();
</handler>
</button>
</view>
</canvas>
Once a connection is established, clients can send and receive messages
using the connectiondatasource tag.
Sample Apps
Sample applications that use the connection tag are:
Superclass Chain
node (LzNode) » datasource (LzDatasource) » datasource (LzHTTPDatasource) » connection (LzConnection)Details
Initial Attributes (7)
Initial Attributes are given as attributes in LZX but are not generally available as properties in JavaScript.
Methods (10)