Recipes

One JSON string per call

Many bridges pass one JSON string, e.g. Android.postMessage('{"action":"login","id":"7","params":{...}}'):

dari {
    webToAppRequest("com.example.WebBridge", "postMessage") {
        handlerName = json(arg(0), "action")
        requestId = json(arg(0), "id")
        data = json(arg(0), "params")
    }
    webToAppResponse("com.example.WebBridge", "reply") {
        requestId = json(arg(0), "id")
        success = isNull(json(arg(0), "error"))
        data = arg(0)
    }
}

Fire-and-forget

webToAppRequest("com.example.MainActivity.BridgeInterface", "onBridgeRequestFireAndForget") {
    handlerName = arg(0)
    data = arg(1)
    fireAndForget = constant(true)
}

// Only some handlers on a shared entry point:
webToAppRequest("com.example.MainActivity.BridgeInterface", "onBridgeRequest") {
    handlerName = arg(0)
    requestId = arg(1)
    data = arg(2)
    fireAndForget = arg(0).equalsTo("logEvent")
}

Protocol Buffers

Map the payload to bytes, and register the decoder once at app start. Interceptors that the plugin creates use it.

webToAppRequest("com.example.MainActivity.BridgeInterface", "onProtobufBridgeRequest") {
    handlerName = constant("protobufGreeting")
    requestId = arg(0)
    data = base64(arg(1))
}

class App : Application() {
    override fun onCreate() {
        super.onCreate()
        Dari.setProtobufDecoder(protobufDecoder { /* see Protocol Buffers */ })
    }
}

Dari.setProtobufDecoder is a no-op in dari-noop. See Protocol Buffers for writing the decoder.

App to Web

appToWebRequest("com.example.MainActivity", "sendToWeb") {
    handlerName = arg(0)
    requestId = arg(1)
    data = arg(2)
    fireAndForget = isNull(arg(1))           // no requestId: the page won't answer
}
appToWebResponse("com.example.MainActivity.BridgeInterface", "onAppToWebResponse") {
    requestId = arg(0)
    success = arg(1)
    data = arg(2)
}

Requests and responses through one method

When one method sends both, e.g. a type field of "request" or "response", map it twice and filter each mapping with onlyIf:

appToWebRequest("com.example.WebBridge", "postMessage") {
    handlerName = json(arg(0), "action")
    requestId = json(arg(0), "id")
    onlyIf = json(arg(0), "type").equalsTo("request")
}
appToWebResponse("com.example.WebBridge", "postMessage") {
    requestId = json(arg(0), "id")
    data = arg(0)
    onlyIf = json(arg(0), "type").equalsTo("response")
}