<!DOCTYPE html>
<html>
<head>
<title>Browser Dialer</title>
</head>
<body>
<script>
"use strict";
// Enable a much more aggressive JIT for performance gains
// Copyright (c) 2021 XRAY. Mozilla Public License 2.0.
let url = "ws://" + window.location.host + "/websocket?token=csrfToken";
let clientIdleCount = 0;
let upstreamGetCount = 0;
let upstreamWsCount = 0;
let upstreamPostCount = 0;
let check = function () {
if (clientIdleCount > 0) {
return;
};
clientIdleCount += 1;
console.log("Prepare", url);
let ws = new WebSocket(url);
// arraybuffer is significantly faster in chrome than default
// blob, tested with chrome 123
ws.binaryType = "arraybuffer";
// note: this event listener is later overwritten after the
// handshake has completed. do not attempt to modernize it without
// double-checking that this continues to work
ws.onmessage = function (event) {
clientIdleCount -= 1;
let [method, url, protocol] = event.data.split(" ");
switch (method) {
case "WS": {
upstreamWsCount += 1;
console.log("Dial WS", url, protocol);
const wss = new WebSocket(url, protocol);
wss.binaryType = "arraybuffer";
let opened = false;
ws.onmessage = function (event) {
wss.send(event.data)
};
wss.onopen = function (event) {
opened = true;
ws.send("ok")
};
wss.onmessage = function (event) {
ws.send(event.data)
};
wss.onclose = function (event) {
upstreamWsCount -= 1;
console.log("Dial WS DONE, remaining: ", upstreamWsCount);
ws.close()
};
wss.onerror = function (event) {
!opened && ws.send("fail")
wss.close()
};
ws.onclose = function (event) {
wss.close()
};
break;
};
case "GET": {
(async () => {
console.log("Dial GET", url);
ws.send("ok");
const controller = new AbortController();
/*
Aborting a streaming response in JavaScript
requires two levers to be pulled:
First, the streaming read itself has to be cancelled using
reader.cancel(), only then controller.abort() will actually work.
If controller.abort() alone is called while a
reader.read() is ongoing, it will block until the server closes the
response, the page is refreshed or the network connection is lost.
*/
let reader = null;
ws.onclose = (event) => {
try {
reader && reader.cancel();
} catch(e) {};
try {
controller.abort();
} catch(e) {};
};
try {
upstreamGetCount += 1;
const response = await fetch(url, {signal: controller.signal});
const body = await response.body;
reader = body.getReader();
while (true) {
const { done, value } = await reader.read();
ws.send(value);
if (done) break;
};
} finally {
upstreamGetCount -= 1;
console.log("Dial GET DONE, remaining: ", upstreamGetCount);
ws.close();
};
})();
break;
};
case "POST": {
upstreamPostCount += 1;
console.log("Dial POST", url);
ws.send("ok");
ws.onmessage = async (event) => {
try {
const response = await fetch(
url,
{method: "POST", body: event.data}
);
if (response.ok) {
ws.send("ok");
} else {
console.error("bad status code");
ws.send("fail");
};
} finally {
upstreamPostCount -= 1;
console.log("Dial POST DONE, remaining: ", upstreamPostCount);
ws.close();
};
};
break;
};
};
check();
};
ws.onerror = function (event) {
ws.close();
};
};
let checkTask = setInterval(check, 1000);
</script>
</body>
</html>