drpc/src/io/net/tcp.js

Distributed RPC

const net = require('net');

class TCP {
    split(buffer) {
        let tail = buffer.split('\r\n');
        let head = tail.pop();
        return {
            head: head,
            tail: tail
        };
    }
    handshake(socket, message, server) {
        try {
            message = JSON.parse(message);
            if (server) {
                if (!(message.password && message.sname && message.password === this.password)) {
                    throw new Error();
                }
                if (message.sname === this.sname) {
                    // prevent self loop
                    throw new Error();
                }
                if (this.list[message.sname]) {
                    // prevent double connection
                    throw new Error();
                }
                socket.write(JSON.stringify({
                    sname: this.sname
                }) + '\r\n');
            } else {
                if (!message.sname) {
                    throw new Error();
                }
                if (message.sname === this.sname) {
                    // prevent self loop
                    throw new Error();
                }
                if (this.list[message.sname]) {
                    // prevent double connection
                    throw new Error();
                }
            }
            socket.sname = message.sname;
            this.list[socket.sname] = socket;
            this.drpc.emit('connect', socket.sname);
        } catch (e) { }
    }
    close(socket) {
        if (socket.sname) {
            delete this.list[socket.sname];
            this.drpc.emit('disconnect', socket.sname);
        }
    }
    init(drpc, port, sname, password) {
        this.drpc = drpc;
        this.port = port;
        this.sname = sname;
        this.password = password;
        this.list = {};
        this.server = net.createServer((socket) => {
            let buffer = '';
            socket.on('data', (chunk) => {
                buffer += chunk.toString();
                let { head, tail } = this.split(buffer);
                buffer = head;
                for (let message of tail) {
                    if (socket.sname) {
                        this.drpc.emit('cast', socket.sname, message);
                    } else {
                        this.handshake.call(this, socket, message, true);
                    }
                }
            });
            socket.on('close', () => {
                this.close.call(this, socket);
            });
            setTimeout(() => {
                if (!socket.sname) {
                    socket.destroy();
                }
            }, 5000);
        });
        this.server.on('listening', () => {
            this.drpc.emit('start');
        });
        this.server.on('error', (error) => {
            this.drpc.emit('error', error);
        });
        this.server.on('close', () => {
            this.drpc.emit('stop');
        });
    }
    start() {
        this.server.listen(this.port, '127.0.0.1');
    }
    stop() {
        for (let name of Object.keys(this.list)) {
            this.list[name].destroy();
            delete this.list[name];
        }
        this.server.close();
    }
    connect(host, port, password) {
        let socket = net.createConnection(port, host, () => {
            let buffer = '';
            socket.on('data', (chunk) => {
                buffer += chunk.toString();
                let { head, tail } = this.split(buffer);
                buffer = head;
                for (let message of tail) {
                    if (socket.sname) {
                        this.drpc.emit('cast', socket.sname, message);
                    } else {
                        this.handshake.call(this, socket, message, false);
                    }
                }
            });
            socket.on('close', () => {
                this.close.call(this, socket);
            });
            socket.write(JSON.stringify({
                password: this.password,
                sname: this.sname
            }) + '\r\n');
        });
    }
    disconnect(sname) {
        this.list[sname].destroy();
    }
    broadcast(message) {
        for (let socket of Object.values(this.list)) {
            socket.write(message + '\r\n');
        }
    }
    multicast(snames, message) {
        for (let sname of snames) {
            let socket = this.list[sname];
            if (socket) {
                socket.write(message + '\r\n');
            }
        }
    }
    unicast(sname, message) {
        let socket = this.list[sname];
        if (socket) {
            socket.write(message + '\r\n');
        }
    }
}

exports.TCP = TCP;