From e019796d978905d546d190f6a09d3af6f23d4df1 Mon Sep 17 00:00:00 2001
From: Paul-Christian Volkmer <paul-christian.volkmer@mni.thm.de>
Date: Sun, 25 May 2014 22:28:08 +0200
Subject: [PATCH] Added CacheControl annotation and interceptor handler
This should enable annotation based cache-control header values.
Added a cache max age of 60 seconds to statistics resource. Proxy-Servers
should cache a statistics resource for about 60 seconds.
---
.../controller/StatisticsController.java | 2 +
.../java/de/thm/arsnova/web/CacheControl.java | 36 +++++++++
.../web/CacheControlInterceptorHandler.java | 75 +++++++++++++++++++
.../webapp/WEB-INF/spring/arsnova-servlet.xml | 4 +
.../controller/StatisticsControllerTest.java | 8 ++
5 files changed, 125 insertions(+)
create mode 100644 src/main/java/de/thm/arsnova/web/CacheControl.java
create mode 100644 src/main/java/de/thm/arsnova/web/CacheControlInterceptorHandler.java
diff --git a/src/main/java/de/thm/arsnova/controller/StatisticsController.java b/src/main/java/de/thm/arsnova/controller/StatisticsController.java
index df5db1bb..3da74456 100644
--- a/src/main/java/de/thm/arsnova/controller/StatisticsController.java
+++ b/src/main/java/de/thm/arsnova/controller/StatisticsController.java
@@ -11,6 +11,7 @@ import org.springframework.web.bind.annotation.RestController;
import de.thm.arsnova.entities.Statistics;
import de.thm.arsnova.services.IStatisticsService;
+import de.thm.arsnova.web.CacheControl;
@RestController
public class StatisticsController extends AbstractController {
@@ -19,6 +20,7 @@ public class StatisticsController extends AbstractController {
private IStatisticsService statisticsService;
@RequestMapping(method = RequestMethod.GET, value = "/statistics")
+ @CacheControl(maxAge = 60, policy = CacheControl.Policy.PUBLIC)
public final Statistics getStatistics() {
return statisticsService.getStatistics();
}
diff --git a/src/main/java/de/thm/arsnova/web/CacheControl.java b/src/main/java/de/thm/arsnova/web/CacheControl.java
new file mode 100644
index 00000000..336c96c2
--- /dev/null
+++ b/src/main/java/de/thm/arsnova/web/CacheControl.java
@@ -0,0 +1,36 @@
+package de.thm.arsnova.web;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target({ ElementType.TYPE, ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface CacheControl {
+ enum Policy {
+ NO_CACHE("no-cache"),
+ NO_STORE("no-store"),
+ PRIVATE("private"),
+ PUBLIC("public");
+
+ private Policy() {
+ this.policyString = null;
+ }
+
+ private Policy(String policyString) {
+ this.policyString = policyString;
+ }
+
+ public String getPolicyString() {
+ return this.policyString;
+ }
+
+ private final String policyString;
+ }
+
+ boolean noCache() default false;
+
+ int maxAge() default 0;
+ Policy[] policy() default {};
+}
diff --git a/src/main/java/de/thm/arsnova/web/CacheControlInterceptorHandler.java b/src/main/java/de/thm/arsnova/web/CacheControlInterceptorHandler.java
new file mode 100644
index 00000000..e72fd61c
--- /dev/null
+++ b/src/main/java/de/thm/arsnova/web/CacheControlInterceptorHandler.java
@@ -0,0 +1,75 @@
+package de.thm.arsnova.web;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.method.HandlerMethod;
+import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
+
+@Component
+public class CacheControlInterceptorHandler extends HandlerInterceptorAdapter {
+
+ @Override
+ public boolean preHandle(
+ HttpServletRequest request,
+ HttpServletResponse response,
+ Object handler) throws Exception {
+
+ setCacheControlResponseHeader(request, response, handler);
+ return super.preHandle(request, response, handler);
+ }
+
+ private void setCacheControlResponseHeader(
+ HttpServletRequest request,
+ HttpServletResponse response,
+ Object handler) {
+
+ CacheControl cacheControl = getCacheControlAnnotation(request, response, handler);
+
+ if (cacheControl == null) {
+ return;
+ }
+
+ StringBuilder headerValue = new StringBuilder();
+
+ if(cacheControl.policy().length > 0) {
+ for (CacheControl.Policy policy : cacheControl.policy()) {
+ if (headerValue.length() > 0) {
+ headerValue.append(", ");
+ }
+ headerValue.append(policy.getPolicyString());
+ }
+ }
+
+ if (cacheControl.noCache()) {
+ if (headerValue.length() > 0) {
+ headerValue.append(", ");
+ }
+ headerValue.append("max-age=0, no-cache");
+ response.setHeader("cache-control", headerValue.toString());
+ }
+
+ if(cacheControl.maxAge() >= 0) {
+ if (headerValue.length() > 0) {
+ headerValue.append(", ");
+ }
+ headerValue.append("max-age=").append(cacheControl.maxAge());
+ }
+
+ response.setHeader("cache-control", headerValue.toString());
+ }
+
+ private CacheControl getCacheControlAnnotation(
+ HttpServletRequest request,
+ HttpServletResponse response,
+ Object handler
+ ) {
+ if (handler == null || !(handler instanceof HandlerMethod)) {
+ return null;
+ }
+
+ final HandlerMethod handlerMethod = (HandlerMethod) handler;
+ return handlerMethod.getMethodAnnotation(CacheControl.class);
+ }
+}
diff --git a/src/main/webapp/WEB-INF/spring/arsnova-servlet.xml b/src/main/webapp/WEB-INF/spring/arsnova-servlet.xml
index d53da559..38376efa 100644
--- a/src/main/webapp/WEB-INF/spring/arsnova-servlet.xml
+++ b/src/main/webapp/WEB-INF/spring/arsnova-servlet.xml
@@ -13,6 +13,10 @@
<mvc:annotation-driven
content-negotiation-manager="contentNegotiationManager" />
+ <mvc:interceptors>
+ <bean class="de.thm.arsnova.web.CacheControlInterceptorHandler" />
+ </mvc:interceptors>
+
<bean id="contentNegotiationManager"
class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
<property name="favorPathExtension" value="false" />
diff --git a/src/test/java/de/thm/arsnova/controller/StatisticsControllerTest.java b/src/test/java/de/thm/arsnova/controller/StatisticsControllerTest.java
index 79f86fcc..52419175 100644
--- a/src/test/java/de/thm/arsnova/controller/StatisticsControllerTest.java
+++ b/src/test/java/de/thm/arsnova/controller/StatisticsControllerTest.java
@@ -2,6 +2,7 @@ package de.thm.arsnova.controller;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.header;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import org.junit.Before;
@@ -59,4 +60,11 @@ public class StatisticsControllerTest {
.andExpect(status().isOk())
.andExpect(content().string("{\"answers\":0,\"questions\":0,\"openSessions\":3,\"closedSessions\":0,\"activeUsers\":0}"));
}
+
+ @Test
+ public final void testShouldGetCacheControlHeaderForStatistics() throws Exception {
+ mockMvc.perform(get("/statistics"))
+ .andExpect(status().isOk())
+ .andExpect(header().string("cache-control", "public, max-age=60"));
+ }
}
--
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