Message Port

Your Web applications can communicate with other Web or native applications. The message data type for the communication is map data, which consists of a string key and value that can be a string, string array, byte stream, or byte stream array.

The Message Port API is mandatory for Tizen Mobile, Wearable, and TV profiles, which means that it is supported on all mobile, wearable, and TV devices. All mandatory APIs are supported on the Tizen emulators.

The main features of the Message Port API include the following:

Sending messages

A Tizen Web application can send messages to another application using the sendMessage() method of the RemoteMessagePort interface (in mobile, wearable, and TV applications).
Receiving messages

To receive response messages from another application, your application can specify a local message port when it sends a message. You can receive response messages using the callback method which is registered through the addMessagePortListener() method of the LocalMessagePort interface (in mobile, wearable, and TV applications).

You can mostly receive message from applications implemented as Tizen native or Web applications. To implement a native application, see the native Message Port Communication guide.

Figure: Sending and receiving messages
Using trusted message ports

For added security, you can restrict communication to only exchange messages with a trusted application that is signed with the same certificate as your application. Use the instances of the LocalMessagePort and RemoteMessagePort interfaces that are retrieved by the requestTrustedLocalMessagePort() and requestTrustedRemoteMessagePort() methods of the tizen.messageport object.

Figure: Trusted message ports

Manage message ports

You can send and receive messages through 2 types of message ports:

The LocalMessagePort interface (in mobile, wearable, and TV applications) is used to register your message port and prepare to receive messages from other applications.

To receive messages from other applications, you must register a callback to the local message port.
The RemoteMessagePort interface (in mobile, wearable, and TV applications) is used to send messages to other applications.

The local message port information can be sent to another application for bi-directional communication, to enable the other application to send response messages.

You can retrieve the instances of the LocalMessagePort and RemoteMessagePort interfaces with the requestLocalMessagePort() and requestRemoteMessagePort() methods of the tizen.messageport object.

Learning how to send messages to and receive responses from other Tizen applications through message ports is a basic data communication skill:

To create a local port which receives messages, use the requestLocalMessagePort() method of the LocalMessagePort interface:
```
var localPort = tizen.messageport.requestLocalMessagePort('SAMPLE_PORT');
```
To retrieve an instance of the RemoteMessagePort interface, use the requestRemoteMessagePort() method of the tizen.messageport object. The RemoteMessagePort interface sends messages to the port identified by an ApplicationId and a port name:
```
var targetApplicationId = tizen.application.getCurrentApplication().appInfo.id;
var remotePort = tizen.messageport.requestRemoteMessagePort(targetApplicationId, 'SAMPLE_PORT');
```

Use the addMessagePortListener() method of the LocalMessagePort interface to add a callback method that is invoked when the message arrives:

var localPortWatchId = localPort.addMessagePortListener(function(data, replyPort) {
    for (var i = 0; i < data.length; i++) {
        var key = data[i].key;
        switch (key) {
            case 'command':
                console.log('key:' + key + ' / value:' + data[i].value);
                break;
            case 'data':
            case 'byteData':
                console.log('key:' + key + ' / value:[');
                for (var j = 0; j < data[i].value.length; j++) {
                    console.log(data[i].value[j] + ', ')
                }
                console.log(']');
                break;
            case 'bytesData':
                console.log('key:' + key + ' / value:[');
                for (var j = 0; j < data[i].value.length; j++) {
                    console.log('[');
                    for (var k = 0; k < data[i].value.length; k++) {
                        console.log(data[i].value[j] + ', ')
                    }
                    console.log(']');
                }
                console.log(']');
                break;
        }
    }
    if (replyPort) {
        console.log('replyPort given: ' + replyPort.messagePortName);
    }
});

Use the sendMessage() method of the RemoteMessagePort interface to send a message:

var messageData = [
    {key:'command', value:'begin'},
    {key:'data', value:{'dummy1', 'dummy2'}},
    {key:'byteData', value:[12, 23, 34, 45, 56, 67, 78]},
    {key:'bytesData', value:[[1, 2, 3, 255], [8, 9, 3, 4, 5]]}
];
remotePort.sendMessage(messageData);

If you expect a response message, pass the instance of the LocalMessagePort interface as the second parameter of the sendMessage() method to specify the message port where the response is sent:

remotePort.sendMessage(messageData, localPort);

Dependencies
- Tizen 2.4 and Higher for Mobile
- Tizen 2.3.1 and Higher for Wearable
- Tizen 3.0 and Higher for TV

Message Port

Manage message ports

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