Question

I am new to Node and Redis, so forgive me if I’m missing something crucial here. I am trying to store a Node.js net.Socket object in Redis, using the node_redis client, so I could reuse a connection made previously on this Socket.
I am storing the socket as a Value as a part of a “users” set:

client.sadd("users", username); //username is a string
client.hmset(username, "ip", socket.remoteAddress, "connection", net.Socket(socket));

At a different point, I am retrieving this socket as:

    client.smembers("users", function(err, replies) {

            replies.forEach(function(reply,i){
            if(recipient == reply) {       //recipient is the username i've got

                    client.hget(reply, "connection", function(err, obj) {
                    console.log("socket's remoteaddress = " +  net.Socket(obj).remoteAddress);
        net.Socket(obj).write("asdasdasd");
            });

            }
    });
    });

But, the:
net.Socket(obj).remoteAddress); is logged as ‘undefined’.
Also,
net.Socket(obj).write(“asdasdasd”); gives me and error saying:

Error: This socket is closed.

So I guess my question is – can you store Sockets this way in Redis and expect them to work upon retrieval? Is there a correct / better way to do this?

P.S. I tried retrieving the Socket without the cast to net.Socket and it still didn’t do any good.

Answer 1

Sockets and socket APIs (such as Berkeley Sockets) intrinsically handle special system-specific resources for which it just wouldn’t make any sense to store or reference on a remote system, or even serialize for that matter.

Although, in reality, sockets are often uniquely identified by file descriptors so you could easily store that small, unique integer in a database for later access; however, that integer would only be meaningful during the active lifetime of that socket within that process instance. A strategy such as this one will be fraught with challenges, mainly having to do with the transient nature of the socket file descriptor number.