Nodejs Express 框架缓存
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Nodejs Express framework caching
提问by Tan Nguyen
I am using Nodejs and Express Js. Also I add NowJS to the Express Js to do some real-time stuffs.
我正在使用 Nodejs 和 Express Js。另外我将 NowJS 添加到 Express Js 来做一些实时的事情。
In the configuration file I have
在配置文件中我有
app.configure('production', function() {
var oneYear = 31557600000;
app.use(express.static(__dirname + '/public', { maxAge: oneYear }));
app.use(express.errorHandler());});
And I run the application using this command:
我使用以下命令运行应用程序：
$ NODE_ENV=production node app.js
However, the files(images, css, js) seem not to be cached, they are always served as new file.
但是，文件（图像、css、js）似乎没有被缓存，它们总是作为新文件提供。
P/s: I have just tested it with localhost, the cache seems to work on localhost, however, when uploading to the server, the cache is not working anymore.
P/s：我刚刚用本地主机测试过，缓存似乎在本地主机上工作，但是，当上传到服务器时，缓存不再工作。
回答by alessioalex
Express is built on Connect, and Connect provides the "static" middleware. Here's the code under the hood for the caching:
Express 建立在 Connect 之上，Connect 提供“静态”中间件。这是缓存的底层代码：
if (!res.getHeader('Cache-Control')) res.setHeader('Cache-Control', 'public, max-age=' + (maxAge / 1000));
You can find that code here:
您可以在此处找到该代码：
https://github.com/senchalabs/connect/blob/master/lib/middleware/static.js#L147
https://github.com/senchalabs/connect/blob/master/lib/middleware/static.js#L147
So as you can see Express is sending a "Cache-Control" header to the browser, telling him to cache that file for a period. So this isn't a "load a file once and then always serve it to all clients", but more of a "tell each client to cache the file the first time he downloads it" (which means all the clients will have to download that file once before it's cached for them).
如您所见，Express 正在向浏览器发送“Cache-Control”标头，告诉浏览器将该文件缓存一段时间。所以这不是“加载一次文件，然后始终将其提供给所有客户端”，而是更多的“告诉每个客户端在第一次下载文件时缓存文件”（这意味着所有客户端都必须下载该文件在为他们缓存之前一次）。
回答by Felix
The following code does the job:
以下代码完成了这项工作：
app.use(function (req, res, next) {
if (req.url.match(/^\/(css|js|img|font)\/.+/)) {
res.setHeader('Cache-Control', 'public, max-age=3600'); // cache header
}
next();
});
回答by vashishatashu
The following code does the trick :
以下代码可以解决问题：
var cacheTime = 86400000*7; // 7 days
app.use(express.static(__dirname + '/public',{ maxAge: cacheTime }));
However my public directory contains CSS as well as html files.
但是，我的公共目录包含 CSS 和 html 文件。
Is there a way i can cache css files only and not html.
有没有办法只缓存css文件而不缓存html。
I tried the setting "no-cache" in meta tag for html file but it didn't work.
我尝试在 html 文件的元标记中设置“无缓存”，但没有用。
回答by Bulat
EDIT: I was wrong, see eug's comment below
编辑：我错了，请参阅下面eug的评论
Connect includes caching middleware: http://senchalabs.github.com/connect/middleware-staticCache.html
Connect 包括缓存中间件：http: //senchalabs.github.com/connect/middleware-staticCache.html
so it should be as easy as
所以应该很简单
app.use(express.cache(...));
app.use(express.static(...));
