How to deal with 'read ETIMEDOUT' in Node.js?

Question

I have a pub/sub model using Node.js to transmit data from one client to another client. Besides, the server also records everything received and sends it to new clients.

However, some data corrupted when transfer, and I got error like:

Error with socket!
{ [Error: write EPIPE] code: 'EPIPE', errno: 'EPIPE', syscall: 'write' }
Error with socket!
{ [Error: read ETIMEDOUT] code: 'ETIMEDOUT', errno: 'ETIMEDOUT', syscall: 'read' }

I don't know how to properly handle these errors. It looks like the client is down.

Since the server is only a proxy like a server, it doesn't really know what data means. I have no idea how to validate every data pack before meeting these errors.

Here is my code:

// server is an object inheriting from net.Server
server.on('listening', function() {
    var port = server.address().port;
}).on('connection', function(cli) {
    cli.socketBuf = new Buffers();
    cli.commandStarted = false;
    cli.dataSize = 0;
    cli.setKeepAlive(true, 10*1000);
    cli.setNoDelay(true);
    cli.on('connect', function() {
        server.clients.push(cli);
    }).on('close', function() {
        var index = server.clients.indexOf(cli);
        server.clients.splice(index, 1);
    }).on('data', function (buf) {
        server.emit('data', cli, buf);
        if(op.autoBroadcast) {
            _.each(server.clients, function(c) {
                if(c != cli) c.write(buf);
            });
        }
    }).on('error', function(err) {
        console.log('Error with socket!');
        console.log(err);
    });
}).on('error', function(err) {
    console.log('Error with server!');
    console.log(err);
});

// ...

// room.dataSocket is an instance of server beyond
room.dataSocket.on('data', function(cli, d) {
    // bf is a buffered file
    bf.append(d);
    room.dataFileSize += d.length;
    
}).on('connection', function(con){
    bf.readAll(function(da) {
        con.write(da);
    });
});

Solution

If you get an EPIPE or indeed any error when writing, the peer has closed or the connection has been dropped. So you must close the connection at that point.

If you get a read timeout the inference is that either you have set an unrealistically short timeout or else the peer has failed to deliver in time: in the second case once again you should assume the connection is down, and close it.

Comments

[liuyanghejerry]

Thanks! Then should I drop received data?

[user207421]

@liuyanghejerry It depends entirely on what you're doing.

[user207421]

@liuyanghejerry Err, it's too bad you asked an unanswerable question that is entirely about how your application works rather than about the API you asked about.