1 files changed, 114 insertions, 0 deletions
diff --git a/protocol.js b/protocol.js
new file mode 100644
index 0000000..a1be542
--- /dev/null
+++ b/protocol.js
@@ -0,0 +1,114 @@
+const util = require("util");
+
+module.exports = {};
+
+module.exports.debug = true;
+
+{
+	let id = 0;
+	function uniqid() {
+		return id++;
+	}
+}
+module.exports.uniqid = uniqid;
+
+function lineReader(conn, lineCb) {
+	let buffer = "";
+	conn.on("data", (data) => {
+		buffer += data.toString();
+		let idx = buffer.indexOf("\n");
+		while (idx != -1) {
+			lineCb(buffer.slice(0, idx));
+			buffer = buffer.slice(idx + 1);
+			idx = buffer.indexOf("\n");
+		}
+	});
+}
+module.exports.lineReader = lineReader;
+
+class Message {
+	constructor(/*...*/) {
+		if (typeof arguments[0] == "number") this.makeReply(...arguments);
+		else this.makeCommand(...arguments);
+	}
+
+	makeCommand(method, ...args) {
+		this.isCommand = true;
+		this.method = method;
+		this.args = args;
+		this.id = uniqid();
+	}
+
+	makeReply(id, res, err) {
+		this.isCommand = false;
+		this.id = id;
+		this.res = res;
+		this.err = err;
+	}
+
+	toJSON() {
+		if (this.isCommand) {
+			return JSON.stringify({
+				method: this.method,
+				args: this.args, 
+				id: this.id,
+			});
+		} else {
+			return JSON.stringify({
+				res: this.res,
+				err: this.err, 
+				id: this.id,
+			});
+		}
+	}
+}
+module.exports.Message = Message;
+
+class Connection {
+	constructor(conn, msgCb) {
+		this.conn = conn;
+		lineReader(conn, (line) => {
+			let obj;
+			try {
+				obj = JSON.parse(line);
+			} catch (e) {
+				if (module.exports.debug) console.log("Invalid JSON received: " + line);
+				return;
+			}
+			if (obj.res || obj.err) {
+				const msg = new Message(obj.id, obj.res, obj.err);
+				if (this.replyHandlers[msg.id]) {
+					this.replyHandlers[msg.id](msg);
+					this.replyHandlers[msg.id] = null;
+				} else {
+					if (module.exports.debug) console.log("Reply for unexpected message id " + msg.id);
+				}
+			} else {
+				msgCb(new Message(obj.method, ...obj.args));
+			}
+		});
+
+		this.replyHandlers = {};
+
+		// Send a ping once in a while
+		this.pingInterval = setInterval(async () => {
+			const msg = await this.send(new Message("ping"));
+			if (module.exports.debug) console.log("Ping reply: " + util.inspect(msg));
+		}, 30000);
+	}
+
+	send(msg) {
+		const data = msg.toJSON();
+		if (module.exports.debug) console.log("Writing to conn: " + data);
+		this.conn.write(data + "\n");
+		return new Promise((resolve, reject) => {
+			this.replyHandlers[msg.id] = resolve;
+		});
+	}
+
+	end() {
+		clearInterval(this.pingInterval);
+		this.conn.end();
+	}
+}
+module.exports.Connection = Connection;