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Test Info:
- Manifest: netwerk/test/mochitests/mochitest.toml
<!DOCTYPE HTML>
<html>
<head>
<title>Test Prefetch Cache: Vary and Cross-Origin Behavior</title>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
</head>
<body>
<p id="display"></p>
<pre id="test">
<script type="application/javascript">
SimpleTest.waitForExplicitFinish();
const SJS_PATH = "/tests/netwerk/test/mochitests/prefetch_cache.sjs";
function getRequestCount(key) {
return fetch(`${SJS_PATH}?key=${key}&mode=count`)
.then(r => r.text())
.then(t => parseInt(t, 10));
}
function resetCount(key) {
return fetch(`${SJS_PATH}?key=${key}&mode=reset`);
}
// True when the test runs inside a cross-origin iframe (mochitest-plain-xorig).
// In that 3p context, fetch()/XHR get a "FETCH" cache enhanceID that
// <link rel=prefetch> does not (network.fetch.cache_partition_cross_origin in
// nsHttpChannel), so prefetch and fetch land in distinct cache scopes.
function isThirdPartyContext() {
try {
return window.top.location.origin !== window.location.origin;
} catch (e) {
return true;
}
}
function prefetchAndWait(url) {
return new Promise((resolve, reject) => {
const link = document.createElement("link");
link.rel = "prefetch";
link.href = url;
link.addEventListener("load", () => resolve(link));
link.addEventListener("error", () => reject(new Error("prefetch failed")));
document.head.appendChild(link);
});
}
function loadScript(url) {
return new Promise((resolve, reject) => {
const script = document.createElement("script");
script.src = url;
script.addEventListener("load", () => {
script.remove();
resolve();
});
script.addEventListener("error", () => {
script.remove();
reject(new Error("script load failed"));
});
document.body.appendChild(script);
});
}
// Vary: Authorization
// 1p context: matching request (no Authorization) reuses the prefetch entry;
// fetch with an explicit Authorization header re-fetches.
// 3p context: fetch()/XHR get a "FETCH" cache enhanceID that prefetch lacks
// (network.fetch.cache_partition_cross_origin in nsHttpChannel), so both
// fetches miss the prefetch entry regardless of Vary.
async function testPrefetchVaryReuse() {
const key = "vary-" + Date.now();
const url = `${SJS_PATH}?key=${key}&type=application/javascript` +
`&cache-control=max-age%3D10000&vary=Authorization`;
const inThirdParty = isThirdPartyContext();
await resetCount(key);
const link = await prefetchAndWait(url);
let count = await getRequestCount(key);
is(count, 1, "Vary: prefetch made exactly one request");
await fetch(url);
count = await getRequestCount(key);
if (inThirdParty) {
is(count, 2, "Vary (3p): fetch did not reuse prefetch entry (partitioned cache scope)");
} else {
is(count, 1, "Vary: matching request reused cache entry");
}
await fetch(url, { headers: { "Authorization": "Bearer test-token" } });
count = await getRequestCount(key);
if (inThirdParty) {
is(count, 3, "Vary (3p): Authorization fetch made another request");
} else {
is(count, 2, "Vary: different Authorization re-fetched from origin");
}
link.remove();
}
// Resolves when the cross-origin popup posts back via SJS notify=opener.
function waitForOpenerMessage(key) {
return new Promise(resolve => {
function onMessage(event) {
if (
event.data &&
event.data.type === "prefetch-nav-loaded" &&
event.data.key === key
) {
window.removeEventListener("message", onMessage);
resolve(event.data);
}
}
window.addEventListener("message", onMessage);
});
}
// Cross-origin prefetch is cached and reused by same-first-party subresource loads.
async function testPrefetchCrossOriginBaseline() {
const key = "x-origin-" + Date.now();
// Mochitests run from mochi.test:8888; example.com is a different origin.
const xOriginUrl =
`&cache-control=max-age%3D10000`;
await resetCount(key);
const link = await prefetchAndWait(xOriginUrl);
let count = await getRequestCount(key);
is(count, 1, "cross-origin: prefetch made exactly one request");
await loadScript(xOriginUrl);
count = await getRequestCount(key);
is(count, 1, "cross-origin: subsequent script load reused prefetch entry");
link.remove();
}
// Prefetch entry is cached but not reused on cross-origin top-level
// navigation: the new top-level lands in a different cache partition.
async function testPrefetchCrossOriginNavigation() {
const key = "x-origin-nav-" + Date.now();
const xOriginUrl =
`&cache-control=max-age%3D10000¬ify=opener`;
await resetCount(key);
const link = await prefetchAndWait(xOriginUrl);
let count = await getRequestCount(key);
is(count, 1, "cross-origin nav: prefetch made exactly one request");
const messagePromise = waitForOpenerMessage(key);
// mochitest-plain: window.open is the only way to get a new top-level
// browsing context (navigating the current window would unload the test).
const popup = window.open(xOriginUrl);
const message = await messagePromise;
popup.close();
count = await getRequestCount(key);
is(
count,
2,
"cross-origin nav: top-level navigation re-fetched (prefetch entry not reused across partitions)"
);
is(
message.count,
2,
"cross-origin nav: popup body reflects the re-fetched response"
);
link.remove();
}
async function runTests() {
await SpecialPowers.pushPrefEnv({
set: [
["network.prefetch-next", true],
],
});
await testPrefetchVaryReuse();
await testPrefetchCrossOriginBaseline();
await testPrefetchCrossOriginNavigation();
SimpleTest.finish();
}
runTests();
</script>
</pre>
</body>
</html>