JSF2 静态资源缓存 [英] JSF2 Static resource caching

问题描述

Glassfish 3.1.2、Mojarra 2.1.6、SSL 激活

Glassfish 3.1.2, Mojarra 2.1.6, SSL activated

我有一个关于静态资源缓存的问题.我已经阅读了一些关于此的帖子，但我不确定我们应该使用哪些选项.这个

I have an question about static resource caching. I´ve read some posts about this but I´m not sure which options we should use. This

https://developers.google.com/speed/docs/best-实践/缓存

也是一篇关于资源缓存的好文章.在我们的应用服务器中，SSL 被激活.我们看到静态资源(图像、脚本、css)没有被缓存.

is also an good article about resource caching. Within our application server SSL is activated. We see that static resources (images, scripts, css) are not cached.

这是我的测试过滤器:

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    if (request instanceof HttpServletRequest && response instanceof HttpServletResponse) {
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse = (HttpServletResponse) response;
        String uri = httpRequest.getRequestURI();
        if (GET_METHOD.equalsIgnoreCase(httpRequest.getMethod()) && uri.contains(ResourceHandler.RESOURCE_IDENTIFIER)) {
            httpResponse.setDateHeader("Expires", System.currentTimeMillis() + 2419200000L); // 1 month in future.
            httpResponse.setDateHeader("Last-Modified", System.currentTimeMillis() - 2419200000L); // 1 month in past.
            httpResponse.setHeader("Cache-Control", "public"); // Secure caching
        }
    }
    chain.doFilter(request, response);
}

• 过期:好的.它是一种不会改变的静态资源，因此我们将到期日期设置为未来一个月.
• 最后修改时间:不确定.我读过将其设置为过去也会影响缓存
• 缓存控制:好的.允许安全缓存.安全影响?

此设置是否有任何影响?我还阅读了很多应该通过过滤器禁用缓存的帖子.我看到的唯一问题是用户可能会在新版本上遇到问题.样式和脚本可以在新版本中更改，但浏览器会忽略新版本并使用缓存中的文件.

Are there any impacts with this settings? I´ve also read a lot of posts where caching should be disabled through an filter. The only problem I see is that users could have a problem on a new release. Styles and Scripts could be changed in the new release but the browser ignore the new one and use the files from cache.

推荐答案

你只需要设置Cache-Control.Expires 和 Last-Modified 已已经默认设置ResourceHandler(并覆盖过滤器设置的值).Last-Modified 必须表示相关资源的最后修改时间戳.您可以通过 servletContext.getResource(path).openConnection().getLastModified() 获取它.但无论如何你都不需要在这里设置它.只需让 ResourceHandler 处理即可.

You only need to set Cache-Control. The Expires and Last-Modified are already set by default ResourceHandler (and would override the values set by your filter). The Last-Modified must represent the last modified timestamp of the resource in question. You can obtain it by servletContext.getResource(path).openConnection().getLastModified(). But you don't need to set it here anyway. Just let ResourceHandler handle.

至于版本控制，只要正确使用资源库即可.您可以在库文件夹中放置一个匹配正则表达式模式 d+(_d+)* 的版本文件夹，ResourceHandler 将提供最新的.

As to versioning, just use resource libraries rightly. You can put a version folder matching regex pattern d+(_d+)* in the library folder and the ResourceHandler will serve the newest.

例如

/resources/libraryname/1_0/js/file.js
/resources/libraryname/1_1/js/file.js
/resources/libraryname/1_2/js/file.js

以下将从 1_2 中获取:

<h:outputScript library="libraryname" name="js/file.js" />

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