cross-origin-iframe-nesting-src-prerender.html

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<!doctype html>

<body>

<script src="/common/get-host-info.sub.js"></script>

<script src="/common/utils.js"></script>

<script src="/speculation-rules/prerender/resources/utils.js"></script>

<script>

async function main() {

  const uid = new URLSearchParams(location.search).get('uid');

  const prerenderChannel = new PrerenderChannel('iframe-with-slm-channel', uid);

  const nestedSameUid = token();

  const nestedSameChannel = new PrerenderChannel('iframe-channel', nestedSameUid);

  const nestedSameQueue = new BroadcastMessageQueue(nestedSameChannel);

  const nestedCrossUid = token();

  const nestedCrossChannel = new PrerenderChannel('iframe-channel', nestedCrossUid);

  const nestedCrossQueue = new BroadcastMessageQueue(nestedCrossChannel);

  // 1. Same-origin nested iframe (relative URL)

  const nestedSameUrl = new URL(

      `cross-origin-iframe-src-prerender.html?uid=${nestedSameUid}`,

      window.location.href);

  const sameIframe = document.createElement('iframe');

  sameIframe.src = nestedSameUrl.href;

  document.body.appendChild(sameIframe);

  // 2. Cross-origin nested iframe (AUTHENTICATED_ORIGIN)

  // The current page is loaded on HTTPS_REMOTE_ORIGIN so AUTHENTICATED_ORIGIN

  // (not HTTPS_REMOTE_ORIGIN) is used as another origin.

  const nestedCrossUrl = new URL(

      `/speculation-rules/prerender/resources/cross-origin-iframe-src-prerender.html?uid=${nestedCrossUid}`,

      get_host_info()['AUTHENTICATED_ORIGIN']);

  const crossIframe = document.createElement('iframe');

  crossIframe.src = nestedCrossUrl.href;

  document.body.appendChild(crossIframe);

  try {

    if (!document.prerendering) {

      throw new Error('The middle iframe itself should be prerendered');

    // Wait for both nested iframes to load during prerendering

    const sameOnload = await nestedSameQueue.nextMessage();

    if (sameOnload !== 'onload. initial_prerendering=true') {

      throw new Error('SLM middle iframe: same-origin nested load failed: ' + sameOnload);

    const crossOnload = await nestedCrossQueue.nextMessage();

    if (crossOnload !== 'onload. initial_prerendering=true') {

      throw new Error('SLM middle iframe: cross-origin nested load failed: ' + crossOnload);

    // Signal onload for this middle iframe

    prerenderChannel.postMessage('onload');

    // Wait for this middle iframe to activate

    await new Promise((resolve) => {

      document.addEventListener('prerenderingchange', () => resolve(), {once: true});

});

    // Wait for both nested iframes to finish prerendering upon activation

    const sameFinish = await nestedSameQueue.nextMessage();

    if (sameFinish !== 'document.prerendering changes to false from true') {

      throw new Error('SLM middle iframe: same-origin nested finish failed: ' + sameFinish);

    const crossFinish = await nestedCrossQueue.nextMessage();

    if (crossFinish !== 'document.prerendering changes to false from true') {

      throw new Error('SLM middle iframe: cross-origin nested finish failed: ' + crossFinish);

    prerenderChannel.postMessage('iframe with SLM finished correctly.');

  } catch (e) {

    prerenderChannel.postMessage('error: ' + e.message);

  } finally {

    prerenderChannel.close();

    nestedSameChannel.close();

    nestedCrossChannel.close();

main();

</script>

</body>