mort
/
xremoteview


			
				
					
						
						
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							let net = require("net");
let fs = require("fs");

let tcpport = process.env["TCPPORT"] ? parseInt(process.env["TCPPORT"]) : 8099;
let httpport = process.env["HTTPPORT"] ? parseInt(process.env["HTTPPORT"]) : 8098;

let html = `
<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>XRemoteView</title>
</head>
<body style="margin: 0px">
	<img
		src="/image"
		style="display: block; object-fit: contain; height: 100vh; width: 100%"
		ondblclick="fullscreen(event.target)">
	<script>
function fullscreen(el) {
	if (document.fullscreenElement) {
		document.exitFullscreen();
	} else if (el.requestFullscreen) {
		el.requestFullscreen();
	}
}
	</script>
</body>
</html>
`;

let boundary = "mjpeg-boundary";

let imgdata = fs.readFileSync("placeholder.jpg");
let waiters = [];

class Reader {
	constructor(stream) {
		this.stream = stream;
		this.buf = Buffer.alloc(0);
		this.resolve = null;
		this.resolveMax = null;
		this.good = true;

		this.stream.on("close", () => {
			this.good = false;
			if (this.resolve) {
				let resolve = this.resolve;
				this.resolve = null;
				resolve(Buffer.alloc(0));
			}
		});

		this.stream.on("error", err => {
			console.log(this.stream.remoteAddress + ": " + err.code);
		});

		this.stream.on("data", data => {
			let resolve = this.resolve;
			let max = this.resolveMax;
			if (resolve && data.length <= this.resolveMax) {
				this.resolve = null;
				resolve(data);
			} else if (this.resolve) {
				this.resolve = null;
				this.buf = data.slice(max);
				resolve(data.slice(0, max));
			} else {
				this.buf = Buffer.concat([this.buf, data]);
			}
		});
	}

	read(max) {
		if (this.buf.length > max) {
			let buf = this.buf.slice(0, max);
			this.buf = this.buf.slice(max);
			return Promise.resolve(buf);
		} else if (this.buf.length != 0) {
			let buf = this.buf;
			this.buf = Buffer.alloc(0);
			return buf;
		} else if (this.good) {
			this.resolveMax = max;
			return new Promise((resolve, reject) => {
				this.resolve = resolve;
			});
		} else {
			return Buffer.alloc(0);
		}
	}

	async readAll(length) {
		if (!this.good) {
			return Buffer.alloc(0);
		}

		let buf = Buffer.alloc(0);
		while (buf.length < length && this.good) {
			let b = await this.read(length - buf.length);
			buf = Buffer.concat([buf, b]);
		}

		return buf;
	}
};

async function respondToHttp(reader, conn) {
	let path = "";
	while (true) {
		let ch = (await reader.readAll(1)).toString();
		if (ch == " ") {
			break;
		} 

		path += ch;
	}

	// We frankly don't care about anything else the client has to say

	if (path == "/image") {
		conn.write(
			"HTTP/1.1 200 OK\r\n" +
			"Content-Type: multipart/x-mixed-replace;boundary=" + boundary + "\r\n" +
			"\r\n");
		conn.write(
			"--" + boundary + "\r\n" +
			"Content-Type: image/jpeg\r\n" +
			"\r\n");
		conn.write(imgdata);
		conn.write(
			"\r\n" +
			"--" + boundary + "\r\n");

		let idx = waiters.length;
		waiters.push({ w: conn, fresh: true });
		conn.on("close", () => {
			delete waiters[idx];
		});
	} else {
		conn.write(
			"HTTP/1.1 200 OK\r\n" +
			"Connection: close\r\n" +
			"Content-Type: text/html\r\n" +
			"\r\n");
		conn.write(html);
		conn.end();
	}
}

net.createServer(async conn => {
	console.log("Connection", conn.remoteAddress);

	let reader = new Reader(conn);

	let magic = await reader.readAll(4);
	if (magic.equals(Buffer.from("GET "))) {
		return respondToHttp(reader, conn);
	}

	let length = magic.readUInt32BE(0);
	let received = Buffer.alloc(0);
	while (reader.good) {
		for (let waiter of waiters) {
			if (waiter == null) continue;
			waiter.fresh = false;
			waiter.w.write(
				"Content-Type: image/jpeg\r\n" +
				"\r\n");
		}

		while (length > 0) {
			let buf = await reader.read(length);
			if (buf.length == 0) {
				console.log(conn.remoteAddress, "disconnected.");
				return;
			}

			for (let waiter of waiters) {
				if (waiter && !waiter.fresh) {
					waiter.w.write(buf);
				}
			}

			received = Buffer.concat([received, buf]);
			length -= buf.length;
		}

		for (let waiter of waiters) {
			if (waiter && !waiter.fresh) {
				waiter.w.write(
					"\r\n" +
					"--" + boundary + "\r\n");
			}
		}

		imgdata = received;

		received = await reader.readAll(4);
		if (received.length < 4) {
			console.log(conn.remoteAddress, "disconnected.");
			return;
		}

		length = received.readUInt32BE(0);
		received = Buffer.alloc(0);
	}
}).on("error", err => console.error(err)).listen(tcpport, "0.0.0.0");
console.log(`TCP listening on 0.0.0.0:${tcpport}`);