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""" Handle the prerendering navigation request and insert the received client
info to the returned page.
"""
import textwrap
html_template = """
<!DOCTYPE html>
<html>
<head>
<title>echo client hints on prerendering page</title>
</head>
<script src="/speculation-rules/prerender/resources/utils.js"></script>
<body>
<script>
// Allow generator to add the received CH information into this script.
%s
const params = new URLSearchParams(location.search);
const uid = params.get('uid');
// Performs the following checks on prerendering pages:
// 1. The client did not send server_received_full_version_list when fetching
// the prerendering main resource.
// 2. The request initiated by the prerendering page is sent with
// sec-ch-ua-full-version-list attached, because the server asked the
// prerendering page to attach this hint for the following requests.
// If any of the checks fails, it will ask the main test page to terminate
// the test.
// Otherwise, it asks the initiator page to perform activation, and informs
// the main test page of the test success upon being activated. This is used
// to verify that the initiator page's client hints cache is not modified by
// the prerendering page, i.e., the initiator page does not attach
// sec-ch-ua-full-version-list to the requests.
async function load_as_prerendering_page() {
// The first prerendering request should not contain the field of
// sec-ch-ua-full-version-list, as prerender is initiated by the initial
// page.
if (!server_received_bitness || server_received_full_version_list) {
failTest(
`Prerender page saw unexpected request headers.
bitness: ${server_received_bitness},
full_version: ${server_received_full_version_list}`,
uid);
}
const r =
await fetch('../resources/echo-subresource-client-hints-received.py');
if (r.status != 200 || r.headers.get('server_received_bitness') !== 'true' ||
r.headers.get('server_received_full_version_list') !== 'true') {
failTest(
`Prerender page saw unexpected headers while fetching
sub-resources.
bitness: ${r.headers.get('server_received_bitness')},
full_version: ${
r.headers.get('server_received_full_version_list')}`,
uid);
} else {
document.onprerenderingchange = () => {
const bc = new PrerenderChannel('test-channel', uid);
// Send the result to the test runner page.
bc.postMessage({result: 'PASSED'});
};
const bc = new PrerenderChannel('prerender-channel', uid);
bc.postMessage('ready for activation');
}
}
load_as_prerendering_page();
</script>
</body>
</html>
"""
def translate_to_js(val: bool) -> str:
if isinstance(val, bool):
return "true" if val else "false"
return ""
def main(request, response):
response.headers.set(b"Accept-CH", "sec-ch-ua-full-version-list")
response.status = 200
# Insert the received hints into script.
content = html_template % (
textwrap.dedent(
f"""
const server_received_bitness =
{translate_to_js(b"sec-ch-ua-bitness" in request.headers)};
const server_received_full_version_list =
{translate_to_js(b"sec-ch-ua-full-version-list" in
request.headers)};
"""
)
)
response.content = content.encode("utf-8")