Node.js实现的BigPipe
以前用PHP实现过，详情点击这里查看《Nginx中的PHP的缓冲问题》
无论用java、.net还是python都是可以实现bigpipe的…
拿那篇文章中的php显示页做示例：
先输出页面的主体结构：
然后按顺序更新页面的内容：
2s后输出header
4s后输出content
6s后输出footer
从加载到显示共消耗约13s (2 + 4 + 6 + 1 ~= 13s)，符合预期结果
这个示例的源码（可复制至本地直接运行）：
/**
* Created with JetBrains WebStorm.
* User: Meteoric_cry
* Date: 13-4-13
* Time: 上午11:10
* To change this template use File | Settings | File Templates.
*/
var http = require('http');
var server = http.createServer(function(req, res) {
res.writeHead(200, {
'Content-Type' : 'text/html',
'Transfer-Encoding' : 'chunked'
});
res.write([
'<!DOCTYPE html>',
'<html>',
'<head>',
'<meta charset="utf-8">',
'<title>Node.js Bigpipe Demo</title>',
'<style type="text/css">',
' * {margin: 0; padding:0;}',
' body {background-color:#fff;}',
' div{border:2px solid #4F81BD; margin:30px; padding: 10px;}',
' p {word-wrap:break-wrod; word-break:break-all; color: #666;}',
' .red {color: #f00;}',
' .blue {color:blue;}',
' .green {color:green;}',
'</style>',
'<script>',
'var g_startTime = new Date();',
'var g_renderArr = []',
'function render(nodeID,html){',
' g_renderArr.push(new Date())',
' document.getElementById(nodeID).innerHTML=html;',
'}',
'</script>',
'</head>',
'<body>',
'<div id="header"><p>Loading...</p></div>',
'<div id="content"><p>Loading...</p></div>',
'<div id="footer"><p>Loading...</p></div>'
].join('\r\n'));
function out_header() {
res.write("<script type='text/javascript'>render('header', '<p><span class=\"blue\">111111</span></p>');</script>\r\n");
setTimeout(out_content, 4 * 1000);
}
function out_content() {
res.write("<script type='text/javascript'>render('content', '<p><span class=\"red\">222222</span></p>');</script>\r\n");
setTimeout(out_footer, 6 * 1000);
}
function out_footer() {
res.write("<script type='text/javascript'>render('footer', '<p><span class=\"green\">333333</span></p>');</script>\r\n");
setTimeout(out_end, 1 * 1000);
}
function out_end() {
res.write([
'<script>',
'var str = [',
' "start:" + g_startTime.toGMTString(),',
' "header:" + g_renderArr[0].toGMTString() + "-" + (g_renderArr[0] - g_startTime) / 1000,',
' "content:" + g_renderArr[1].toGMTString() + "-" + (g_renderArr[1] - g_renderArr[0]) / 1000,',
' "footer:" + g_renderArr[2].toGMTString() + "-" + (g_renderArr[2] - g_renderArr[1]) / 1000,',
' "end:" + new Date().toGMTString() + "-" + (new Date() - g_renderArr[2]) / 1000 + "-" + (new Date() - g_startTime) / 1000',
'].join("\\n");',
'alert(str);',
'</script>'
].join(''));
res.end("\r\n</body></html>");
}
setTimeout(out_header, 2 * 1000);
}).listen(3002);
上面是将界面的显示顺序固定写死了，下面将展示一个灵活的动态界面：
先输出6个内容容器，然后构建6个客户端请求，当收到请求数据时直接返回给客户端。如果你需要让界面的内容按顺序显示，只需要修改，返回的delay值，比如按索引值的大小进行修改
1: var params = url.parse(request.url, true);
2: var delay = params.query.id * 3000; console.log(delay);
这个示例的完整源码：
/**
* Created with JetBrains WebStorm.
* User: zhangyi
* Date: 13-4-23
* Time: 上午10:57
* To change this template use File | Settings | File Templates.
*/
var http = require('http');
var sys = require('sys');
var url = require("url");
http.createServer(function(request, response) {
response.writeHead(200, {"Content-Type" : "text/html"});
response.write("<!Doctype html><html><head>");
response.write("<style type='text/css'>div{border:2px solid #4F81BD; margin:30px; padding: 10px;}</style>");
response.write("<script type=\"text/javascript\">function arrived(id,text) { var b=document.getElementById(id); b.innerHTML = text; }</script>");
response.write("</head><body><div>Progressive Loading");
for(var i = 0; i < 6; i++) {
response.write("<div id='" + i + "'>Loading...</div>");
}
response.write("</div>");
var down = 6;
for (i = 0; i < 6; i++) {
var proxy = http.createClient(2000, "localhost");
var proxyRequest = proxy.request("GET", "/?id=" + i, {"host" : "localhost"});
proxyRequest.addListener('response', function (proxyResponse) {
--down;
proxyResponse.addListener('data', function(chunk) {
response.write(chunk, 'binary');
});
proxyResponse.addListener('end', function() {
if(down == 0) {
response.end();
}
});
});
proxyRequest.end();
}
response.write("</body></html>");
}).listen(8080);
http.createServer(function(request, response) {
var delay = Math.round(Math.random() * 8000);
/*
var params = url.parse(request.url, true);
var delay = params.query.id * 3000; console.log(delay);
*/
setTimeout(function() {
var params = url.parse(request.url, true);
var id = params.query.id;
response.writeHead(200, {"Content-Type" : "text/html"});
var content = "<span>Content of Module " + id + "</span>";
response.write("<script>" +
"arrived('" + id + "', '" + content + "');" +
"</script>");
response.end();
}, delay);
}).listen(2000);
上面的示例中并没有像第一个例子一样，显示输出header信息（'Transfer-Encoding' : 'chunked'），而浏览器，在response里却看到了，猜测是node.js在输出的时候内部加上去的。
相比php，node.js内部实现并没有“缓冲池”的功能，都是直接输出，很简单吧…
本文参考：
