JSComm

These libraries allow to easily share JS interfaces between a 'client' (a window) and a 'server' (another window), using secure postMessages.

Usage

Server

What we call server here is the window which will expose the API. Any class can be exposed using the register() method, but all of its methods have to take a callback as last parameter so that they can notify the client when they return.

A new instance of the API will be created for each window requesting it.

var MathAPI = function ( ) { };
MathAPI.prototype.addition = function ( a, b, callback ) { callback( null, a + b ); };

var server = new APIServer( );
server.register( 'math', MathAPI );

Client

The client is the window which will use the API. Before getting an hold on an API, you will have to open it before, by using the use() method of the APIClient class and passing it a callback. This callback will then be called when a bridge toward the server will be established. From this point, you will be able to use the remote API just like you would use a standard JS object (check the Limitations section for more informations).

<iframe id="api-server" src="http://example.org"></iframe>

The client will be able to request then use an API exposed by #api-server using the following code :

window.addEventListener( 'load', function ( ) {

    var target = document.getElementById( 'api-server' ).contentWindow;
    var client = new APIClient( target );

    client.use( 'math', function ( err, api ) {

        if ( err )
            throw err;

        // The API can be used here, using the `api` parameter.

        api.addition( 10, 10, function ( err, result ) {
            alert( '10 + 10 = ' + result );
        } );

    } );

} );

Limitations

• Exported API prototypes cannot be changed after beeing registered (they're frozen).
• You cannot return non-serializable values (ie. they have to be JSON-compatible).
• There is no way to have a synchronous communication between the client and the server.