在Node.js中如何从处理程序/callback方法发送消息到客户端
我是node.js的初学者。 我正在尝试使用node.js创build一个webapp，它将在云中创build服务器并对其进行pipe理。 在做了一些研究之后，我决定使用node.js，socket.io，express和pkgcloud模块来创buildwebapp。 现在，我面临的问题是，当服务器创build时，我无法将消息发送到前端/客户端。 服务器正在成功创build，但我不知道如何将服务器状态发送到浏览器屏幕。
这是代码：index.js
var express = require('express'), app = express(); app.use(express.static(__dirname + '/')); var io = require('socket.io').listen(app.listen(1337)); io.sockets.on('connection', function(socket) { socket.on('mesg_to_server', function(data) { // This is for testing whether we're receiving msgs on client side io.sockets.emit("mesg_to_client",{ mesg: data["mesg"], mesg1: data["mesg1"] }); var Rackspace = require('./ex_rackspace'); var rackspace = new Rackspace(); rackspace.create(data.mesg); }); }); ex_rackspace.js：
var pkgcloud = require('pkgcloud'), _ = require('./node_modules/pkgcloud/node_modules/underscore'); var client = pkgcloud.providers.rackspace.compute.createClient({ username: 'xxxx', apiKey: 'xxxxx', region: 'HKG' }); // This function will handle our server creation, // as well as waiting for the server to come online after we've // created it. function handleServerResponse(err, server) { if (err) { console.dir(err); return; } console.log('SERVER CREATED: ' + server.name + ', waiting for active status'); // Wait for status: ACTIVE on our server, and then callback server.setWait({ status: server.STATUS.running }, 5000, function (err) { if (err) { console.dir(err); return; } console.log('SERVER INFO'); console.log(server.name); console.log(server.status); console.log(server.id); console.log('Make sure you DELETE server: ' + server.id + ' in order to not accrue billing charges'); }); } var Rackspace = function() { }; Rackspace.prototype.test = function (text) { console.log("provider: Rackspace: " + text); } // first we're going to get our flavors Rackspace.prototype.create = function (server) { client.getFlavors(function (err, flavors) { if (err) { console.dir(err); return; } // then get our base images client.getImages(function (err, images) { if (err) { console.dir(err); return; } var flavor = _.findWhere(flavors, { name: '1 GB Performance' }); var image = _.findWhere(images, { name: 'CentOS 5 (PV)' }); // Create our first server client.createServer({ name: server, image: image, flavor: flavor }, handleServerResponse); }); }); } module.exports = Rackspace;
page.html（客户端）：
<!DOCTYPE html> <html> <head> <script src="/socket.io/socket.io.js"></script> <script type="text/javascript"> // our socket.io code goes here var socketio = io.connect("127.0.0.1:1337"); socketio.on("mesg_to_client", function(data) { document.getElementById("chatlog").innerHTML = ("<hr/>" + data.mesg + ' ' + data.mesg1 + document.getElementById("chatlog").innerHTML); }); socketio.on("test_output", function(data) { console.log(data.mesg); }); function sendMessage() { var msg = document.getElementById("mesg_input").value; socketio.emit("mesg_to_server", { mesg : msg, mesg1 : "here"}); } </script> </head> <body> <input type="text" id="mesg_input"/> <button onclick="sendMessage()">Create</button> <div id="chatlog"></div> </body> </html>
你需要添加一个callback到创build函数
Rackspace.prototype.create = function (server, callback){ //your code - if err send error else send success message callback(err, message) }
然后在调用create时使用它
rackspace.create(data.mesg, function (err, message){ //your code with your socket emit here });