在这里,我执行了SELECT
查询where User_id=1
。在这里,我需要从会话中获取user_id
而不是“1”。 (如果php Session包含user_id
)
我是Node Js的新手。
//server.js
var app = require('http').createServer(handler),
io = require('socket.io').listen(app),
fs = require('fs'),
express=require('express'),
session=require('express-session'),
mysql = require('mysql'),
connectionsArray = [],
connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: '',
database: 'test',
port: 3306
}),
POLLING_INTERVAL = 3000,
pollingTimer;
var appp=express();
appp.get('/',function (req, res){
res.json({ uid: req.uid });
});
// If there is an error connecting to the database
connection.connect(function(err) {
// connected! (unless `err` is set)
if (err) {
console.log(err);
}
});
// creating the server ( localhost:8000 )
app.listen(8000);
// on server started we can load our client.html page
function handler(req, res) {
fs.readFile(__dirname + '/client.php', function(err, data) {
if (err) {
console.log(err);
res.writeHead(500);
return res.end('Error loading client.php');
}
res.writeHead(200);
res.end(data);
});
}
/*
*
* HERE IT IS THE COOL PART
* This function loops on itself since there are sockets connected to the page
* sending the result of the database query after a constant interval
*
*/
var pollingLoop = function() {
// Doing the database query
var query = connection.query('SELECT * FROM users where user_id=1'),
users = []; // this array will contain the result of our db query
// setting the query listeners
query
.on('error', function(err) {
// Handle error, and 'end' event will be emitted after this as well
console.log(err);
updateSockets(err);
})
.on('result', function(user) {
// it fills our array looping on each user row inside the db
users.push(user);
})
.on('end', function() {
// loop on itself only if there are sockets still connected
if (connectionsArray.length) {
pollingTimer = setTimeout(pollingLoop, POLLING_INTERVAL);
updateSockets({
users: users
});
} else {
console.log('The server timer was stopped because there are no more socket connections on the app')
}
});
};
// creating a new websocket to keep the content updated without any AJAX request
io.sockets.on('connection', function(socket) {
console.log('Number of connections:' + connectionsArray.length);
// starting the loop only if at least there is one user connected
if (!connectionsArray.length) {
pollingLoop();
}
socket.on('disconnect', function() {
var socketIndex = connectionsArray.indexOf(socket);
console.log('socketID = %s got disconnected', socketIndex);
if (~socketIndex) {
connectionsArray.splice(socketIndex, 1);
}
});
console.log('A new socket is connected!');
connectionsArray.push(socket);
});
var updateSockets = function(data) {
// adding the time of the last update
data.time = new Date();
console.log('Pushing new data to the clients connected ( connections amount = %s ) - %s', connectionsArray.length , data.time);
// sending new data to all the sockets connected
connectionsArray.forEach(function(tmpSocket) {
tmpSocket.volatile.emit('notification', data);
});
};
console.log('Please use your browser to navigate to http://localhost:8000');