在Dropwizard中设置静态资产的缓存控制标头

Question

在Dropwizard服务中设置静态资产的缓存控制头的最佳方法是什么？

一些谷歌搜索出现了一个AssetsBundle构造函数:

AssetsBundle(String resourcePath,com.google.common.cache.CacheBuilderSpec cacheBuilderSpec,String uriPath)

然而,经过进一步调查,看起来com.yammer.dropwizard.bundles软件包自版本5.1以来就不属于Dropwizard.

也许我错过了一些明显的东西,但有没有一种首选方法来处理这个问题？

Answer 1

如果有人感兴趣(根据这个问题的观点数量判断,它们可能不是),这就是我解决这个问题的方法.

我在与Service类相同的包中创建了一个CacheControlFilter类:

public class CacheControlFilter implements Filter{

    public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {

        HttpServletResponse resp = (HttpServletResponse) response;

        // Add whatever headers you want here
        resp.setHeader("Cache-Control", "public, max-age=500000");
        resp.setHeader("Expires", new Date().getTime()+500000 + "");

        chain.doFilter(request, response);
    }

    public void destroy() {}

    public void init(FilterConfig arg0) throws ServletException {}
}

然后在服务类中,只需添加以下行:

env.addFilter(new CacheControlFilter(), "/*");

当然,您可能会更精细,并为图像文件和css文件添加不同的过滤器,但这会为所有请求添加标头.

来自评论:

对于dropwizard 1.0.6.只需注册

env.servlets()
   .addFilter("MyFilter", new CacheControlFilter())
   .addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST), true, "/*") 

Answer 2

根据 Tim Barclay 的答案，我创建了一个过滤器，如果请求的资源是扩展名为 js、css、png、jpg、gif 或 svg 的文件，则Cache-Control设置Expires未来一年的过滤器。否则缓存将被禁用。

希望它对某人有帮助！

protected void setCacheHeaders(Environment environment, String urlPattern, int seconds) {
    FilterRegistration.Dynamic filter = environment.servlets().addFilter(
            "cacheControlFilter",
            new Filter() {
                @Override
                public void init(FilterConfig filterConfig) throws ServletException {

                }

                @Override
                public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

                    HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
                    HttpServletResponse httpServletResponse = (HttpServletResponse) servletResponse;

                    String[] cacheFileTypes = {"js","css","png","jpg","gif","svg"};
                    String filetypeRequested = FilenameUtils.getExtension(httpServletRequest.getRequestURL().toString());

                    if (httpServletRequest.getMethod() == "GET" && seconds > 0 && Arrays.asList(cacheFileTypes).contains(filetypeRequested)) {
                        httpServletResponse.setHeader("Cache-Control", "public, max-age=" + seconds);
                        Calendar c = Calendar.getInstance();
                        c.setTime(new Date());
                        c.add(Calendar.SECOND, seconds);
                        SimpleDateFormat format = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss zzz", Locale.US);
                        format.setTimeZone(TimeZone.getTimeZone("GMT"));
                        httpServletResponse.setHeader("Expires", format.format(c.getTime()));
                    } else {
                        httpServletResponse.setHeader("Cache-Control", "no-cache, no-store, must-revalidate");
                        httpServletResponse.setHeader("Expires", "0");
                        httpServletResponse.setHeader("Pragma", "no-cache");
                    }

                    filterChain.doFilter(servletRequest, servletResponse);

                }

                @Override
                public void destroy() {

                }
            }
    );
    filter.addMappingForUrlPatterns(EnumSet.allOf(DispatcherType.class), true, urlPattern);
}

PS：我无法得到接受的答案的方式来设置 -headerExpires工作：

resp.setHeader("Expires", new Date().getTime()+500000 + "");

相比之下，我的非常臃肿，但它有效：

Calendar c = Calendar.getInstance();
c.setTime(new Date());
c.add(Calendar.SECOND, seconds);
SimpleDateFormat format = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss zzz", Locale.US);
format.setTimeZone(TimeZone.getTimeZone("GMT"));
httpServletResponse.setHeader("Expires", format.format(c.getTime()));