如何实现使用socket.io的时间

Question

I believe I have surfed the web enough but still cant get any resources on the topic. How can I implement the 'time-to-live' function with Socket.io ?

I am using Node.js with express . The above mentioned time-to-live function is intended to work as described below:

If I specify timeToLive = 10; secs, clients that connect in less than 10 sec after the message is emitted should still get the message. This function is available on some of the cloud messaging libraries like GCM .

Any online resource will appreciated.

Answer 1

There is no such functionality in socket.io . You will have to implement it yourself. Consider using an array of objects that holds messages and Date.now() of that message and loop it when a user connects. Delete any messages that are expired and emit the ones that are still valid . Minimum code could be this but due to heavy use of splice it could be slow.

var messages = [];
var TTL = 10;


io.on('connection', function (socket) {
   for(i = 0; i < messages.length; i++)
       if(messages[i].time + TTL < Date.now())
           messages.splice(i, 1);
   socket.emit('data', messages);
});

Consider using redis or any other high performance database to also synchronize between multiple servers if you require that: