Testing for off-line in a Worklight app - geolocation

Question

What is the best way to test if a Worklight app is off-line?
After I use the WL.Device.startAcquisition( ... ) api to start stuff off, I am currently using:
WL.Device.Geo.acquirePosition(function(pos) {
console.log("***** Aquired position ***** " + JSON.stringify(pos));
}, function(error) {
console.log(JSON.stringify("***** Unable to aquire position ***** " + error.code + ' : ' + error.message));
// call method to asynchronously - periodicallyCheckIfOnline( ... );
}, {timeout: 5000});
And if I determine that I am offline, I then use the watchPosition api to periodically test for a new connection.
navHandle = navigator.geolocation.watchPosition(onSuccess, onError, { timeout: 5000 });
Once I get the connection back I then clear the watch.
navigator.geolocation.clearWatch(navHandle);
Is this the best way of doing it or are there better Worklight APIs to use for this.
Note: I am trying to test this in a Mobile Browser Simulator scenario hence the short timeouts.

Answer 1

On startup, use something like
WL.Client.connect({onSuccess:onConnectSuccess,onFailure:onConnectFailure,timeout:number_of_ms});
to check if you have initial connectivity.
To detect any further changes in connectivity, you can use the
WL.Client.setHeartBeatInterval(number_of_s) API.
This will 'ping' the worklight server every number_of_s seconds and fire the WL.Events.WORKLIGHT_IS_DISCONNECTED and WL.Events.WORKLIGHT_IS_CONNECTED events, to which you attach callbacks to as described in the reading-worthy tutorial linked to by #Leandro David.
NOTE : if you need to use network to transfer heavy data, do a double check : once you know you have connectivity to the worklight server, use the WL.Device.getNetworkInfo API to check the connection quality before sending/receiving data.

Answer 2

There is a tutorial about dealing with online/offline mode in the worklight geting started material ("Working Offline" link):
http://www.ibm.com/developerworks/mobile/worklight/getting-started.html#GS_work_offline
It tells the best way to use Worklight API to deal with online/offline connection
To summarize, I believe this is the most important part:
Active detection of connectivity
Connectivity loss can be detected in two locations in your application code:
– Application initialization – WL.Client.init() method, typically called from initOptions.js file
– Adapter procedure invocation – WL.Client.invokeProcedure() method
-To add connectivity failure detection in either location, add the onConnectionFailure property and specify a callback function to be invoked if connectivity fails
var wlInitOptions = {
onConnectionFailure: function (data){
connectionFailure(data);
},
or
WL.Client.invokeProcedure(invocationData, {
onSuccess: successHandlerFunction,
onConnectionFailure: connectionFailure,
timeout: 1000
});
Passive detection – Offline and online events
Each time the Worklight framework attempts to access the Worklight Server, it might detect that the application switched from offline to online status or vice versa.
In both cases, JavaScript events are fired:
– WL.Events.WORKLIGHT_IS_DISCONNECTED event is fired when connectivity to the Worklight Server fails
– WL.Events.WORKLIGHT_IS_CONNECTED event is fired when connectivity to the Worklight Server is restored
You can add event listeners to these events and specify the callback functions to handle them.
document.addEventListener(WL.Events.WORKLIGHT_IS_CONNECTED, connectDetected, false);
document.addEventListener(WL.Events.WORKLIGHT_IS_DISCONNECTED, disconnectDetected, false);
Note: WL.Events.WORKLIGHT_IS_DISCONNECTED and WL.Events.WORKLIGHT_IS_CONNECTED are namespace constants, not strings
There are more details available in the tutorial above