我是 Node.js 的初学者。我正在尝试使用 node.js 创建一个 web 应用程序，它将在云中创建服务器并管理它们。经过一些研究后，我决定使用 node.js、socket.io、express 和 pkgcloud 模块来创建 web 应用程序。现在，我面临的问题是在创建服务器时无法向前端/客户端发送消息。服务器已成功创建，但我不知道如何将服务器状态发送到浏览器屏幕。
代码如下: 索引.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>
最佳答案
您需要向创建函数添加回调
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
});
关于node.js - 在 Node.js 中如何从处理程序/回调方法向客户端发送消息，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28218093/