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"use strict";
function handleRequest(request, response) {
// write to raw socket
response.seizePower();
let qs = new URLSearchParams(request.queryString);
let imgs = [];
let new_hint = true;
let new_header = true;
for (const [imgUrl, uuid] of qs.entries()) {
if (new_hint) {
// we need to write a new header
new_hint = false;
response.write("HTTP/1.1 103 Early Hint\r\n");
}
if (!imgUrl.length) {
// next hint in new early hint response when empty string is passed
new_header = true;
if (uuid === "new_response") {
new_hint = true;
response.write("\r\n");
} else if (uuid === "non_link_header") {
response.write("Content-Length: 25\r\n");
}
response.write("\r\n");
} else {
// either append link in new header or in same header
if (new_header) {
new_header = false;
response.write("Link: ");
} else {
response.write(", ");
}
// add query string to make request unique this has the drawback that
// the preloaded image can't accept query strings on it's own / or has
// to strip the appended "?uuid" from the query string before parsing
imgs.push(`<img src="${imgUrl}?${uuid}" width="100px">`);
response.write(`<${imgUrl}?${uuid}>; rel=preload; as=image`);
}
}
if (!new_hint) {
// add separator to main document
response.write("\r\n\r\n");
}
let body = `<!DOCTYPE html>
<html>
<body>
${imgs.join("\n")}
</body>
</html>`;
// main document response
response.write("HTTP/1.1 200 OK\r\n");
response.write("Content-Type: text/html;charset=utf-8\r\n");
response.write("Cache-Control: no-cache\r\n");
response.write(`Content-Length: ${body.length}\r\n`);
response.write("\r\n");
response.write(body);
response.finish();
}