Class AndroidMessagingConfig

Android shared messaging configuration. This class should be constructed once and then shared between features (because of the way it modifies globals).

For example, if Android is injecting a JavaScript module like C-S-S which contains multiple 'sub-features', then this class would be instantiated once and then shared between all sub-features.

The following example shows all the fields that are required to be passed in:

const config = new AndroidMessagingConfig({
    // a value that native has injected into the script
    messageSecret: 'abc',

    // the name of the window method that android will deliver responses through
    messageCallback: 'callback_123',

    // the `@JavascriptInterface` name from native that will be used to receive messages
    javascriptInterface: "ARandomValue",

    // the global object where methods will be registered
    target: globalThis
});
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Once an instance of AndroidMessagingConfig is created, you can then use it to construct many instances of Messaging (one per feature). See examples/android.example.js for an example.

Native integration

Assuming you have the following:

• a @JavascriptInterface named "ContentScopeScripts"
• a sub-feature called "featureA"
• and a method on "featureA" called "helloWorld"

Then delivering a NotificationMessage to it, would be roughly this in JavaScript (remember params is optional though)

const secret = "abc";
const json = JSON.stringify({
    context: "ContentScopeScripts",
    featureName: "featureA",
    method: "helloWorld",
    params: { "foo": "bar" }
});
window.ContentScopeScripts.process(json, secret)
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When you receive the JSON payload (note that it will be a string), you'll need to deserialize/verify it according to "Messaging Implementation Guide"

Responding to a RequestMessage, or pushing a SubscriptionEvent

If you receive a RequestMessage, you'll need to deliver a MessageResponse. Similarly, if you want to push new data, you need to deliver a SubscriptionEvent. In both cases you'll do this through a global window method. Given the snippet below, this is how it would relate to the AndroidMessagingConfig:

• $messageCallback matches AndroidMessagingConfig.messageCallback
• $messageSecret matches AndroidMessagingConfig.messageSecret
• $message is JSON string that represents one of MessageResponse or SubscriptionEvent

object ReplyHandler {
    fun constructReply(message: String, messageCallback: String, messageSecret: String): String {
        return """
            (function() {
                window['$messageCallback']('$messageSecret', $message);
            })();
        """.trimIndent()
    }
}
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