Get the client id of the message sender in socket.io?

on the server开发者_如何学Python side i got

socket.on('chat', function (data) {
    io.sockets.socket(data.clientid).emit('chat', {
        msg: data.msg,
        senderid : senderid
    });
});

How can I get the get the senderid without the sender having to post their clientid through with the message?

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It turns out I can just use socket.id of the user sending through a msg to get their clientid, such as:

  socket.on('chat', function (data) {
      io.sockets.socket(data.clientid).emit('chat', {
          msg: data.msg,
          senderid : socket.id
      }); 
  });

Originally I thought I could just fetch the clientid by doing :

  io.sockets.on('connection', function (socket) {
     clientid = socket.id;

But clientid will be the last person who connected in this instance, not the last person who sent through a chat

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I'd suggest sending over a username (make sure it's unique) and keeping an object of client ids associated with usernames in memory.