Receiving Unfiltered Messages¶

Backendless Real-Time Messaging delivers messages to listeners added to a channel. A listener is a callback function which is invoked by Backendless to deliver a message to the client application. Depending on the API used to add a listener, it can receive either all messages published into the channel or a filtered subset of messages. The filtering options are explained in greater detail in the Receiving Filtered Messages section of this guide.

Receiving String Messages¶

Adding a listener to receive messages as string objects. Messages should be published as string objects):

var channel = Backendless.Messaging.subscribe( "MyChannel" );

function onMessage( stringMessage ) {
  console.log( "Message received: " + stringMessage.data )
}

channel.addMessageListener( onMessage );

Receiving Dictionary/Map messages¶

Adding a listener to receive messages as dictionary/map objects. Messages can be published as JSON objects, complex types or disctionary/map objects:

var channel = Backendless.Messaging.subscribe( "MyChannel" );

function onMessage( message ) {
  console.log( "Message received" );
  console.log( "Property x " + message.data.x )
  console.log( "Property y " + message.data.y )
}

channel.addMessageListener( onMessage );

Receiving custom type/class messages¶

Adding a listener to receive messages as instances of a custom type (the Person class). Published messages must be instances of the class, map/dictionary objects or JSON objects with the same structure as the class:

var channel = Backendless.Messaging.subscribe( "MyChannel" );

function onMessage( message ) {
  console.log( "Message received" );
  console.log( "Property name " + message.data.name )
  console.log( "Property age " + message.data.age )
}

channel.addMessageListener( onMessage );

General signature¶

A general signature for receiving messages as instances of a custom type:

// channel object must be obtained via a subscription call, for example:
// var channel = Backendless.Messaging.subscribe( "MyChannel" );
channel.addMessageListener( function( message ) { } );