什么是Socket.io中的.acks键

Question

My client socket has a property called socket.acks . This property continuously grows, and within a few minutes, there are over 5000 enteries in it.

They look something like this:

acks:
   { '11': [Function],
     '12': [Function],
     '13': [Function],
     '14': [Function],
     '15': [Function],
     '16': [Function],
     '17': [Function],
   }

EDIT

My server acts as a proxy to sending information between two clients.

Server

// Assume client1 is a reference to client1 socket, and client2 is for client2
socket.on('on_data_from_client1', function (data, cb) {
    // Here data and cb are sent to client2. 
    // I guess this is causing the .acks to be added since I am 
    // passing a function as last parameter to .emit.
    // But It is not me who should worry about the callback, but rather client2
    client2.emit('data_from_client1', data, cb);
});

Answer 1

Looking through the code, it's an object that contains unacknowledged messages.

Once a message has been acknowledged, it will be removed from this object, so I'm guessing that your client isn't acknowledging messages while the server is expecting acknowledgement to happen.

More information here .

EDIT

I've never used a similar setup so no idea if it's supposed to work at all (I foresee issues with unacknowledged messages when one of the clients disconnects, although I haven't looked close enough at the socket.io implementation to see if any pending acks will be cleaned up properly in that case).

The only possible solution I can think of right now is this (although it's functionally the same as yours):

socket.on('on_data_from_client1', function (data, cb) {
  client2.emit('data_from_client1', data, function(moreData) {
    return cb(moreData);
  });
});