使用Nodejs实现聊天服务器

两年前在项目中使用nodejs+socket.io+redis实现的聊天和推送服务器,
基本上几百行代码就实现了整个功能,在项目中单服务器单进程可以跑到支持
5000人左右同时在线。

主要思路

  1. 用户上线后,根据用户的userid和socket,保存到一个全局的map中
  2. 发送消息时,根据对方的userid找到对应的socket,通过socket.emit发送消息给对方
  3. 如果对方不在线,在redis中保留消息,在对方上线后推送给用户
  4. 用户下线后,从全局的map中删除对应的用户socket
  5. 由于需要保持长连接,客户端需要定时发心跳给服务端,所以定义了一个心跳消息,可以5分钟发一次
  • 用户上线

    io.sockets.on('connection', function (socket) {
    var address = socket.handshake.address;
    console.log(Date() + " New connection from " + address.address + ":" + address.port);
    socket.on('login', function (userinfo) {
    userid = userinfo.myAuraId
    var address = socket.handshake.address;
    var deviceid = userinfo.deviceId
    console.log(Date() + " Login from " + address.address + ":" + address.port + " " + userid + " " + deviceid);
    old_socket = sockets[userid]
    if (old_socket && old_socket.deviceid && deviceid && old_socket.deviceid != deviceid) {
    old_socket.relogin = 1
    old_socket.emit('logout')
    console.log("logout " + old_socket.userid + " " + old_socket.deviceid)
    }
    if (old_socket && old_socket != socket) {
    old_socket.disconnect()
    }
    socket.relogin = 0
    socket.userid = userid
    socket.deviceid = deviceid
    //发送离线消息
    send_store_msg(socket, userid)
    sockets[userid] = socket
    //通知业务服务器,用户已登录
    pub.publish("login_message_channel", JSON.stringify(userinfo))
    })
  • 发送消息

    socket.on('chat', function (msg, ack) {
    //process_msg(msg)
    pub.publish("chat_filter_channel", JSON.stringify(msg))
    socket.userid = msg.from
    sockets[socket.userid] = socket
    if (ack) {
    ack(1)
    }
    })
  • 接收和回应心跳

    socket.on('hb', function (msg, ack) {
    if (ack) {
    ack(1)
    }
    })
  • 用户下线,删除对应的socket

    socket.on("disconnect", function () {
    var address = socket.handshake.address;
    console.log(Date() + " Disconnect from " + address.address + ":" + address.port);
    if (!socket.relogin) {
    delete sockets[socket.userid]
    }
    })

推送服务器

实现了聊天服务器后,对推送来说就很简单了

  1. 在redis里开个channel,业务服务器往这个channel里publish数据
  2. nodejs subscribe这个channel监听数据,找到对应用户发送消息即可。
  3. 用户不在线,可能也需要对这个离线推送消息做保留,具体看业务定义
var notification = redis.createClient()
notification.subscribe("notification")
// check redis notifcation channel
notification.on("message", function (pattern, msg) {
var msgobj = JSON.parse(msg)
var keys = msgobj.toWho
var needStore = msgobj.needStore
for (index in keys) {
var key = keys[index]
if (!needStore) {
if (sockets[key]) {
sockets[key].emit("notification", msg)
}
}
else {
var list = []
store.hget("nodejs_notification", key, function (e, v) {
if (v) {
list = JSON.parse(v);
}
list.push(msg)
var msglist = JSON.stringify(list)
store.hset("nodejs_notification", key, msglist, function (e, r) {
})
})
if (sockets[key]) {
send_notification(sockets[key], msg)
}
}
}
})
function send_notification(socket, notif) {
socket.emit("notification", notif, function ack() {
store.hdel("nodejs_notification", socket.userid)
})
}

客户端Lib库

服务端是使用socket.io实现,基本上socket.io的Lib都能兼容

以下是推荐的两个客户端Lib:

其他语言版本,可以在github搜索socket.io,找到对应的Lib库

Server端全部代码

//var io = require('socket.io').listen(80)
var app = require('http').createServer(handler)
, io = require('socket.io').listen(app)
app.listen(80);
function handler(req, res) {
if (req.url == "/monitor") {
res.writeHead(200);
res.end("OK");
}
else {
res.writeHead(404);
res.end();
}
}
//io.disable('heartbeats')
//io.set('heartbeats', false);
io.set('transports', ['websocket', 'xhr-polling']);
io.set('heartbeat timeout', 5 * 60)
io.set('heartbeat interval', 4 * 60)
io.set('close timeout', 1 * 30);
io.set("log level", 1)
io.set("browser client", false)
io.set("browser client cache", false)
io.set("browser client cache", false)
var redis = require("redis")
var pub = redis.createClient()
var store = redis.createClient()
var snschat = redis.createClient()
var notification = redis.createClient()
var PUSH_TO_IOS_DELAY_TIME = 120000
snschat.subscribe("snschat");
notification.subscribe("notification")
var sockets = {}
pub.on("error", function (err) {
console.log("Error " + err);
});
store.on("error", function (err) {
console.log("Error " + err);
});
snschat.on("error", function (err) {
console.log("Error " + err);
});
function send_msg_delay(socket) {
store.hget("chat_history", socket.userid, function (e, v) {
if (v) {
list = JSON.parse(v);
if (list.length > 0) {
var msg = JSON.stringify(list)
socket.isSendingChatMessage = false
send_msg(socket, msg)
}
}
})
}
function send_msg(socket, msg) {
//delay for 5 sec
if (socket.isSendingChatMessage) {
setTimeout(function () {
send_msg_delay(socket)
}, 5000)
return
}
socket.isSendingChatMessage = true
//start send
var callSendToIOS = sendToIOSDealy(socket.userid, PUSH_TO_IOS_DELAY_TIME)
socket.emit("chat", msg, function ack(size) {
clearTimeout(callSendToIOS)
store.hget("chat_history", socket.userid, function (e, v) {
if (v) {
list = JSON.parse(v);
//console.log("size="+size)
if (list.length == size) {
store.hdel("chat_history", socket.userid, function (e, r) {
})
}
else if (size < list.length) {
list = list.splice(size)
var msglist = JSON.stringify(list)
store.hset("chat_history", socket.userid, msglist, function (e, r) {
})
}
}
socket.isSendingChatMessage = false
})
})
}
function sendToIOSDealy(toWho, time) {
return setTimeout(function () {
sendToIOS(toWho)
}, time)
}
function sendToIOS(toWho) {
var obj = {"toWho": toWho}
var msg = JSON.stringify(obj)
console.log("delay send to ios channel:" + msg)
pub.publish("chat_message_channel", msg)
}
function send_notification(socket, notif) {
socket.emit("notification", notif, function ack() {
store.hdel("nodejs_notification", socket.userid)
})
}
function send_store_msg(socket, userid) {
if (socket.isSendStoreMsg) {
return;
}
socket.isSendingChatMessage = false
store.hget("chat_history", userid, function (e, msg) {
if (msg) {
send_msg(socket, msg)
store.hdel("chat_history", socket.userid, function (e, r) {
})
}
})
store.hget("nodejs_notification", userid, function (e, msg) {
if (msg) {
var msglist = JSON.parse(msg)
for (var i = 0; i < msglist.length; i++) {
send_notification(socket, msglist[i])
}
//socket.emit("notification", msg)
//store.hdel("nodejs_notification", userid)
}
})
socket.isSendStoreMsg = true
}
function saveToChatHistory(msg) {
var list = []
store.hget("chat_history", msg.to, function (e, v) {
if (v) {
list = JSON.parse(v);
}
list.push(msg)
var msglist = JSON.stringify(list)
store.hset("chat_history", msg.to, msglist, function (e, r) {
})
})
}
function pushToChatHistoryChannel(msg) {
var msgStr = JSON.stringify(msg)
pub.publish("chat_message_history_channel", msgStr)
}
function process_msg(msg) {
var list = []
store.hget("chat_history", msg.to, function (e, v) {
if (v) {
list = JSON.parse(v);
}
list.push(msg)
var msglist = JSON.stringify(list)
store.hset("chat_history", msg.to, msglist, function (e, r) {
})
if (sockets[msg.to]) {
send_msg(sockets[msg.to], msglist)
}
else {
sendToIOS(msg.to)
}
pushToChatHistoryChannel(msg)
})
}
// check redis notifcation channel
notification.on("message", function (pattern, msg) {
var msgobj = JSON.parse(msg)
var keys = msgobj.toWho
var needStore = msgobj.needStore
for (index in keys) {
var key = keys[index]
if (!needStore) {
if (sockets[key]) {
sockets[key].emit("notification", msg)
}
}
else {
var list = []
store.hget("nodejs_notification", key, function (e, v) {
if (v) {
list = JSON.parse(v);
}
list.push(msg)
var msglist = JSON.stringify(list)
store.hset("nodejs_notification", key, msglist, function (e, r) {
})
})
if (sockets[key]) {
send_notification(sockets[key], msg)
}
}
}
})
// check redis snschat channel
snschat.on("message", function (pattern, data) {
msg = JSON.parse(data)
process_msg(msg)
})
io.sockets.on('connection', function (socket) {
var address = socket.handshake.address;
console.log(Date() + " New connection from " + address.address + ":" + address.port);
socket.on('login', function (userinfo) {
userid = userinfo.myAuraId
var address = socket.handshake.address;
var deviceid = userinfo.deviceId
console.log(Date() + " Login from " + address.address + ":" + address.port + " " + userid + " " + deviceid);
old_socket = sockets[userid]
if (old_socket && old_socket.deviceid && deviceid && old_socket.deviceid != deviceid) {
old_socket.relogin = 1
old_socket.emit('logout')
console.log("logout " + old_socket.userid + " " + old_socket.deviceid)
}
if (old_socket && old_socket != socket) {
old_socket.disconnect()
}
socket.relogin = 0
socket.userid = userid
socket.deviceid = deviceid
send_store_msg(socket, userid)
sockets[userid] = socket
pub.publish("login_message_channel", JSON.stringify(userinfo))
})
socket.on('geo', function (geo, ack) {
if (geo.myAuraId) {
var now = new Date()
pub.publish("geo", JSON.stringify({
geo: geo, time: now.getTime()
}))
socket.userid = geo.myAuraId
sockets[socket.userid] = socket
if (ack) {
ack(1)
send_store_msg(socket, userid)
}
}
})
socket.on('chat', function (msg, ack) {
//process_msg(msg)
pub.publish("chat_filter_channel", JSON.stringify(msg))
socket.userid = msg.from
sockets[socket.userid] = socket
if (ack) {
ack(1)
}
})
socket.on('hb', function (msg, ack) {
if (ack) {
ack(1)
}
})
socket.on("disconnect", function () {
var address = socket.handshake.address;
console.log(Date() + " Disconnect from " + address.address + ":" + address.port);
if (!socket.relogin) {
delete sockets[socket.userid]
}
})
})


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