DIAL 2.2.1 Server Implementation

XCAST Overview

The RDK DIAL server supports XCAST_2 API through thunder plugin interface

XCAST_2 API

setEnabled

void setEnabled(boolean);

Enable or disable XCAST service. Default value is true. When disabled, the customer should not be able to discover CPE as a cast target for any client application. After enable(true) server application manger must re-register all app that are available for user to cast.

The value is persisted on device after each call. Upon reboot or reconnect, the persisted value is used until the next call.

getEnabled

object getEnabled(void)

Return the persisted value in json object Object Parameter

{
  "enabled" :  "true"|"false"
}

onApplicationLaunchRequest

void onApplicationLaunchRequest(Object)

Fired when service receives a launch request from client. If not already running, the requested app is started. if already running and in background mode, the requested app enters foreground mode (optimus::running, xcast::running). If already in foreground mode, the request does not change app state.

This request must result in an onApplicationStateChanged event

Object parameter

{
  applicationName : <string> registered application name
  parameters: type information see below
 /*
  * The format and interpretation of 'parameter values' is determined between the (app launcher
  * or cast target) and the cast client for each application. But overall, the parameter string
  * conforms to the following pattern:
  *
  * parameters: {
  *   "url" : <string> "dialpayload=...&&additionalDataUrl=...[&&{query_string}]
  * }
  *
  * where in the `url` value,
  * `dialpayload` is the url-encoded HTTP POST payload from DIAL launch request
  * `additionalDataUrl` is a local URL generated by DIAL server for application to communicate with.
  * `query_string` contains all the url-encoded query strings in the HTTP POST request.
 */
}

onApplicationStopRequest

void onApplicationStopRequest(Object)

Fired when service receives an stop request from cast client. If the app is already running and either in foreground or background mode, then the requested app is destroyed (optimus::destroyed, xcast::stopped). If the app is not running, this request triggers an error onApplicationStateChanged message with error = "Invalid"

This request must result in an onApplicationStateChanged event

Object parameter

{
  applicationName : <string> registered application name
  applicationId: [string] (optional) application instance Id.
}

onApplicationStateRequest

void onApplicationStateRequest(object)

Fired when service needs an update of application state.

This request must result in an onApplicationStateChanged event

Object parameter

{
  applicationName: <string> name of the application whose state is being requested
  applicationId: [string] (optional) application instance Id.
}

onApplicationStateChanged

void onApplicationStateRequest(object)

Notify whenever app changes state (due to user activity or internal error or other reasons). For singleton, applicationId is optional

If application launch/stop request is denied or fails to reach the target state or the state change is triggered by an internal error, a predefined error string should be included. This error may be translated from DIAL http error code to a XCAST client's error code.

Object parameter

{
  serviceName: [string] (optional) name of the service that the request originates from (DIAL, Alexa etc.)
  applicationName: <string> name of the application whose state has changed.
  applicationId: [string] (optional) application instance Id,
  state: <string> Predefined state strings. [running|stopped],
  error: [string] (optional) Predefined Error string from cast target app [none|forbidden|unavailable|invalid|internal]
}

Client Error Mapping Example:

XCastService Error	Definition	DIAL Client Error
none (or absent)	request (start/stop) is fulfilled successfully	HTTP 200 OK
forbidden	user is not allowed to change the state of the app (This is not related to user account authentication of the native app)	HTTP 403 Forbidden
unavailable	the target native app is not available on the device	HTTP 404 Not Found
invalid	the request is invalid (bad param for example)	HTTP 400 Bad Request
internal	the server fail to fulfill the request (server error)	HTTP 500 Internal