SharedBufferReceivedEvent class

Package:

WebView2Script

Event object for the chrome.webview.sharedbufferreceived event. This event is dispatched when CoreWebView2.PostSharedBufferToScript is successfully called.

Extends

Event

Remarks

Examples

The following example sends data to script for one-time, read-only consumption.

First, in the native host app code, set data into the shared memory:

wil::com_ptr<ICoreWebView2ExperimentalEnvironment10> environment;
CHECK_FAILURE(
    m_appWindow->GetWebViewEnvironment()->QueryInterface(IID_PPV_ARGS(&environment)));

wil::com_ptr<ICoreWebView2ExperimentalSharedBuffer> sharedBuffer;
CHECK_FAILURE(environment->CreateSharedBuffer(bufferSize, &sharedBuffer));
// Add data to shared memory via IStream.
wil::com_ptr<IStream> stream;
CHECK_FAILURE(sharedBuffer->OpenStream(&stream));
CHECK_FAILURE(stream->Write(data, sizeof(data), nullptr));
PCWSTR additionalDataAsJson = L"{\"myBufferType\":\"bufferType1\"}";
if (fromFrame)
{
    m_webviewFrame4->PostSharedBufferToScript(
        sharedBuffer.get(), COREWEBVIEW2_SHARED_BUFFER_ACCESS_READ_ONLY,
        additionalDataAsJson);
}
else
{
    m_webView18->PostSharedBufferToScript(
        sharedBuffer.get(), COREWEBVIEW2_SHARED_BUFFER_ACCESS_READ_ONLY,
        additionalDataAsJson);
}
// Close the one-time shared buffer, to release resources.
sharedBuffer->Close();

In the HTML document, subscribe to and handle sharedbufferreceived event.

Next, in the HTML document, subscribe to and then handle the sharedbufferreceived event:

window.chrome.webview.addEventListener("sharedbufferreceived", e => {
    SharedBufferReceived(e);});

let readOnlySharedBuffer;
function ShowReadOnlySharedBuffer() {
    if (readOnlySharedBuffer) {
        DisplaySharedBufferData(readOnlySharedBuffer);
    } else {
        // Post a web message to ask host to share the one time read only buffer.
        chrome.webview.postMessage("RequestOneTimeShareBuffer");
    }
}

function DisplaySharedBufferData(buffer) {
    document.getElementById("shared-buffer-data").value =
        new TextDecoder().decode(new Uint8Array(buffer));
}

function SharedBufferReceived(e) {
    if (e.additionalData && e.additionalData.myBufferType == "bufferType1") {
        readOnlySharedBuffer = e.getBuffer();
    } else {
        sharedBuffer = e.getBuffer();
    }
    DisplaySharedBufferData(e.getBuffer());
}

function ReleaseBuffer(buffer) {
    window.chrome.webview.releaseBuffer(buffer);
}

Properties

additionalData	An object that is the result of parsing the additionalDataAsJson parameter to CoreWebView2.PostSharedBufferToScript as a JSON string. This property will be undefined if additionalDataAsJson is nullptr or the empty string.
source	The source of the event is the chrome.webview object.

Methods

getBuffer()

Returns an ArrayBuffer object with the backing content from the shared buffer passed to CoreWebView2.PostSharedBufferToScript. If CoreWebView2.PostSharedBufferToScript was called with the buffer set to ReadOnly, then only read access is allowed to the buffer. If you try to modify the content in a read-only buffer, it will cause an access violation in the WebView renderer process and crash the renderer process.

Property Details

additionalData

An object that is the result of parsing the additionalDataAsJson parameter to CoreWebView2.PostSharedBufferToScript as a JSON string. This property will be undefined if additionalDataAsJson is nullptr or the empty string.

additionalData: any;

Property Value

any

source

The source of the event is the chrome.webview object.

source: WebView;

Property Value

WebView

Method Details

getBuffer()

Returns an ArrayBuffer object with the backing content from the shared buffer passed to CoreWebView2.PostSharedBufferToScript. If CoreWebView2.PostSharedBufferToScript was called with the buffer set to ReadOnly, then only read access is allowed to the buffer. If you try to modify the content in a read-only buffer, it will cause an access violation in the WebView renderer process and crash the renderer process.

getBuffer(): ArrayBuffer;

Returns

ArrayBuffer

An ArrayBuffer over the shared buffer passed to CoreWebView2.PostSharedBufferToScript.