节点，socket.io-将新条目添加到新闻提要中时更新客户端? [英] node, socket.io - update client when new entry added to news feed?
问题描述
我用socket.io创建了node的client和server. server正在执行4个get新闻订阅源请求并获取了数据.这些数据通过socket.io发送到client.
I've created client and server of node with socket.io. server is executing 4 get requests of news feed and fetched the data. These data is sent to the client with socket.io.
client在发生特定socket.io事件时显示新闻提要.
这一次很好.这是代码和工作小提琴
client is displaying news feed on the occurrence of specific socket.io event.
This works well for once. Here is the code and working fiddle
server.js
var app = require('http').createServer(handler)
, io = require('socket.io').listen(app)
, fs = require('fs')
, redis = require("redis");
var http = require("http");
// initialize the container for our data
var data = "";
var nfs = [
"http://economictimes.feedsportal.com/c/33041/f/534037/index.rss",
"http://www.timesonline.co.uk/tol/feeds/rss/uknews.xml",
"http://www.independent.co.uk/news/business/rss",
"http://www.dailymail.co.uk/money/index.rss"
];
//setInterval(function() {
for(var i=0; i<nfs.length; i++){
//console.log(nfs[i]);
http.get(nfs[i], function (http_res) {
// this event fires many times, each time collecting another piece of the response
http_res.on("data", function (chunk) {
// append this chunk to our growing `data` var
data += chunk;
});
// this event fires *one* time, after all the `data` events/chunks have been gathered
http_res.on("end", function () {
// you can use res.send instead of console.log to output via express
console.log("data received");
});
});
}
//}, 30000);
app.listen(8080);
function handler (req, res) {
fs.readFile(__dirname + '/client.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading index.html');
}
res.writeHead(200);
res.end(data);
});
}
io.on('connection', function (socket) {
//setInterval(function() {
socket.emit('news', data);
/*socket.on('my other event', function (data) {
console.log(data);
});*/
//}, 5000);
});
client.html
<html>
<head>
<script src="https://cdn.socket.io/socket.io-1.2.1.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script>
//socket io client
var socket = io.connect('http://localhost:8080');
//on connetion, updates connection state and sends subscribe request
socket.on('connect', function(data){
setStatus('connected');
socket.emit('subscribe', {channel:'notif'});
});
//when reconnection is attempted, updates status
socket.on('reconnecting', function(data){
setStatus('reconnecting');
});
//on new message adds a new message to display
socket.on('news', function (data) {
console.log(data);
//socket.emit('my other event', { my: 'data' });
addMessage(data);
});
/*socket.on('news', function (data) {
debugger;
socket.emit('my other event', { my: 'data' }
var msg = "";
if (data) {
msg = data;
}
addMessage(msg);
});*/
//updates status to the status div
function setStatus(msg) {
$('#status').html('Connection Status : ' + msg);
}
//adds message to messages div
function addMessage(msg) {
//debugger;
var $xml = $(msg);
var html = '';
$xml.find("item").each(function() {
var $item = $(this);
html += '<li>' +
'<h3><a href ="' + $item.find("link").text() + '" target="_new">' +
$item.find("title").text() + '</a></h3> ' +
'<p>' + $item.find("description").text() + '</p>' +
// '<p>' + $item.attr("c:date") + '</p>' +
'</li>';
});
$('#result').prepend(html);
}
</script>
</head>
<body>
<div id="status"></div><br><br>
<ul id="result"></ul>
</body>
</html>
我对socket.io的了解是，我们不需要长时间的服务器轮询，因此server如何知道将新闻添加到了受人尊敬的新闻提要中.
What I understand about socket.io is that we don't need long server polling and so how do server come to know that news is added to the respected news feed.
将新闻添加到新闻提要rss中时，如何使用新添加的新闻更新client?
How do I update the client with newly added news when news is added to the news feed rss ???
更新
好的，因此从所有响应中我都得出结论，socket.io不可能知道已添加新条目.因此，我怎么知道(哪些工具/库确实需要知道已经添加了新条目并更新了客户端)???
Update
Ok so from all the responses I get the point that it is not possible for socket.io to know that new entry has been added. So, how do I know (which tools/libraries do require to know that new entry has beed added and update the client as well) ???
推荐答案
从新闻提要中检索消息完全独立于socket.io，除非新闻提要在其末端实现套接字并且您的服务器成为其客户端.因此，您将不得不继续使用http请求对它们进行轮询，以了解它们是否具有更新的数据.
Retrieving the messages from the news feeds are completely independent of socket.io unless the news feeds implement sockets on their end and your server becomes their client. So you will have to continue to poll them with http requests to know whether they have updated data.
为了通知您的客户更新，您只需发出新闻事件.大概您在服务器上会有逻辑，以确保您只发送以前未发送过的事件.
In order to notify your clients of the update you would just emit the news event. Presumably you would have logic on the server to make sure you are only sending events which have not previously be sent.
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