在我的部署中设置Cache-Control no-cache,no-store是什么？

Question

Cache-Control: no-cache
Cache-Control: no-store
Expires:Thu, 01 Jan 1970 00:00:00 GMT
Pragma:no-cache

我正在使用：

Spring 3.1.2.发布

Primefaces JSF 3.4.1

null

我没有什么想法了，有人知道是什么在我的响应中设置这些头，以便我可以针对适当的部署组件来解决这个问题吗？

Answer 1

导致这种情况的根代码在Spring MVC中，从WebContentGenerator调用。该类用作MVC/Webflow堆栈中几个类的基类：WebContentInterceptor（MVC interceptor）、AbstractController（MVC controller）、AbstractHandlerMethodAdapter（MVC HandlerAdapter）、AnnotationMethodHadlerAdapter（MVC HandlerAdapter）、FlowHandlerAdapter（MVC HandlerAdapter）、FlowHandlerAdapter（Webflow HandlerAdapter）、JSFlow HandlerAdapter（Webflow HandlerAdapter）

CacheControl seconds设置为0调用preventCaching方法。因此，应用程序似乎默认设置为0。

web.servlet.support.WebContentGenerator

protected final void preventCaching(HttpServletResponse response) {
    response.setHeader(HEADER_PRAGMA, "no-cache");
    if (this.useExpiresHeader) {
        // HTTP 1.0 header
        response.setDateHeader(HEADER_EXPIRES, 1L);
    }
    if (this.useCacheControlHeader) {
        // HTTP 1.1 header: "no-cache" is the standard value,
        // "no-store" is necessary to prevent caching on FireFox.
        response.setHeader(HEADER_CACHE_CONTROL, "no-cache");
        if (this.useCacheControlNoStore) {
            response.addHeader(HEADER_CACHE_CONTROL, "no-store");
        }
    }
}

我发现，由于我使用的是JSF+Webflow，JSFloWHandlerAdapter首先处理对流/视图的服务器请求。这就是为什么配置拦截器没有帮助，因为JsfFlowHandlerAdapter此时已经设置了Cache-Control和其他HTTP头。事实证明，我已经扩展了JsfFlowHandlerAdapter来处理FlowExecutionRestorationFailureException（请参见Sping Web Flow防止Back按钮的使用），所以我所需要做的就是设置我想要的配置ala WebContentInterceptor（因为这些配置属于基类WebContentGenerator）。

自定义JsfFlowHandlerAdapter

public class MyAppFlowHandlerAdapter extends org.springframework.faces.webflow.JsfFlowHandlerAdapter {
     ...
    }

webmvc-config.xml

<!-- Dispatches requests mapped to flows to FlowHandler implementations -->
    <bean
        class="com.myapp.MyAppFlowHandlerAdapter">
        <property name="flowExecutor" ref="flowExecutor" />
            <!-- Disable built in Cache-Control settings -->
        <property name="cacheSeconds" value="-1" />
        <property name="useExpiresHeader" value="false" />
        <property name="useCacheControlHeader" value="false" />
        <property name="useCacheControlNoStore" value="false" />
    </bean>

<!-- Maps request paths to flows in the flowRegistry; e.g. a path of /hotels/booking 
    looks for a flow with id "hotels/booking" -->
<bean class="org.springframework.webflow.mvc.servlet.FlowHandlerMapping">
    <!-- snip out unimportant -->
    <property name="interceptors">
        <list>
            <ref bean="cacheControlInterceptor" />  
        </list>
    </property>
</bean>
    <bean id="cacheControlInterceptor"
    class="com.myapp.CacheControlInterceptor">

public class CacheControlInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
            //Example below: set your Cache-Control, expires, pragma headers here
        response.setHeader("Cache-Control", "private");

        return true;
    }
}