Runtime Events & Utility Functions

The E3DS Frontend SDK provides a set of callbacks and control functions that allow you to monitor session lifecycle events, handle errors gracefully, and extend user experience with custom UI or application logic.

1. Error Handling & Session Control

Prevent Error Redirect

If enabled, the SDK will not redirect users to an error page on streaming failure.
Developers can instead show their own UI message.

let preventErrorRedirect = true;

onError

Triggered when any streaming or connection error occurs.

e3ds_controller.callbacks.onError = function(errorMsg){
    console.error("onError:", errorMsg);
};

Use Case Examples:

• Show custom “Connection Failed” UI

• Log errors for analytics

• Retry connection logic

onSessionExpired

Called when the authentication session token expires.

e3ds_controller.callbacks.onSessionExpired = function(){
    self.location = "assets/pages/session-expired.htm";
};

Recommended Actions:

• Redirect to your own session expired page

• Regenerate token

• Auto-reconnect flow

2. Connection & Data Channel Events

onConfigAcquire

Called when streaming configuration has successfully been retrieved.

e3ds_controller.callbacks.onConfigAcquire = function(){
    console.log("onConfigAcquire");
};

Use this to:

• Confirm configuration readiness

• Trigger UI state updates

onDataChannelOpen

Fires when the WebRTC data channel with Unreal Engine is successfully opened.

e3ds_controller.callbacks.onDataChannelOpen = function(){
    console.log("onDataChannelOpen");
};

onDataChannelClose

Triggered when the data channel closes.

e3ds_controller.callbacks.onDataChannelClose = function(){
    console.log("onDataChannelClose");
};

Use these to:

• Enable/disable UI controls

• Detect unexpected session drops

3. Unreal Communication

onResponseFromUnreal

Receives messages sent back from Unreal.

e3ds_controller.callbacks.onResponseFromUnreal = function(descriptor){
    console.log("UnrealResponse:", descriptor);
};

Typical Uses:

• Receive gameplay state updates

• Handle UX responses

• Debug Unreal messaging

4. Streaming Progress Events

These callbacks provide real-time progress updates while the app is initializing.

App Acquisition Progress

e3ds_controller.callbacks.onReceivingAppAcquiringProgress = function(percent){
    console.log("App Acquiring:", percent);
};

App Preparation Progress

e3ds_controller.callbacks.onReceivingAppPreparationProgress = function(percent){
    console.log("App Preparing:", percent);
};

App Starting Progress

e3ds_controller.callbacks.onReceivingAppStartingProgress = function(percent){
    console.log("App Starting:", percent);
};

Ideal for:

• Custom loading screens

• Progress bars

• User feedback during startup

5. HTML Binding Event

onHtmlBind

Triggered once HTML and streaming UI are fully bound.

e3ds_controller.callbacks.onHtmlBind = function(){
    console.log("onHtmlBind");
};

Useful when:

• Initializing UI overlays

• Binding custom buttons

• Performing final setup

6. Stream Control Functions

The SDK also exposes several helpful runtime control utilities.

Terminate Stream

Stops the current streaming session.

e3ds_controller.terminate();

Use when:

• User exits experience

• Navigating away from page

• Handling shutdown logic

Control Video Quality

Allows manual control of quality bitrate.

e3ds_controller.setQualityPoint(value);
// Acceptable values: 1 - 51

Note:

• Lower value → higher quality

• Higher value → lower quality

Quality Values

Recommendations

Good for:

• Low bandwidth users

• Performance optimization

Set Stream Volume

e3ds_controller.setVolume(value);
// 0 to 1

Capture Screenshot

e3ds_controller.captureScreenShot();

Toggle Fullscreen

e3ds_controller.toggleFullscreen();

Send Message to Unreal

Allows sending structured messages to Unreal Engine.

e3ds_controller.sendToUnreal(descriptor);

Typical usage:

• Game commands

• UI interactions

• Custom remote controls

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