VIVO-117 Turn off HTTP caching unless explicitly enabled in runtime.properties.

doc/install.html

@@ -649,6 +649,26 @@
                             remote_userID 
                         </td>
                     </tr>
+                    
+                    <tr>
+                        <td colspan="2">
+                            Tell Vitro to generate HTTP headers on its responses to facilitate caching the 
+                            profile pages that it creates. This can improve performance, but it can also
+                            result in serving stale data. Default is false if not set.
+                            For more information, see the VIVO wiki page: 
+                            <a href="https://wiki.duraspace.org/display/VIVO/Use+HTTP+caching+to+improve+performance">
+                            Use HTTP caching to improve performance </a>
+                        </td>
+                    </tr>
+                    <tr class="odd_row">
+                        <td>
+                          http.createCacheHeaders
+                        </td>
+                        <td>
+                           true
+                        </td>
+                    </tr>
+                    
                     <tr>
                         <td colspan="2">
                           Force VIVO to use a specific language or Locale instead of those 

webapp/config/example.runtime.properties

@@ -120,6 +120,19 @@ proxy.eligibleTypeList = http://www.w3.org/2002/07/owl#Thing
 #
 RDFService.languageFilter = true
 
+#
+# Tell VIVO to generate HTTP headers on its responses to facilitate caching the 
+# profile pages that it creates. 
+#
+# For more information, see 
+# https://wiki.duraspace.org/display/VIVO/Use+HTTP+caching+to+improve+performance
+#
+# Developers will likely want to leave caching disabled, since a change to a
+# Freemarker template or to a Java class would not cause the page to be 
+# considered stale.
+#
+# http.createCacheHeaders = true
+
 #
 # Force VIVO to use a specific language or Locale instead of those 
 # specified by the browser. This affects RDF data retrieved from the model, 

webapp/src/edu/cornell/mannlib/vitro/webapp/filters/CachingResponseFilter.java

@@ -37,6 +37,8 @@ import edu.cornell.mannlib.vitro.webapp.utils.solr.SolrResultsParser;
 /**
  * Assist in cache management for individual profile pages.
  * 
+ * Must be enabled in runtime.properties.
+ * 
  * Only works for users who are not logged in.
  * 
  * The Solr index must be configured to keep an ETAG on each individual's
@@ -72,6 +74,7 @@ public class CachingResponseFilter implements Filter {
 			.getLog(CachingResponseFilter.class);
 
 	private static final String PROPERTY_DEFAULT_NAMESPACE = "Vitro.defaultNamespace";
+	private static final String PROPERTY_ENABLE_CACHING = "http.createCacheHeaders";
 	private static final String ETAG_FIELD = "etag";
 
 	private static final FieldMap parserFieldMap = SolrQueryUtils.fieldMap()
@@ -79,12 +82,14 @@ public class CachingResponseFilter implements Filter {
 
 	private ServletContext ctx;
 	private String defaultNamespace;
+	private boolean enabled;
 
 	@Override
 	public void init(FilterConfig fc) throws ServletException {
 		ctx = fc.getServletContext();
-		defaultNamespace = ConfigurationProperties.getBean(ctx).getProperty(
+		ConfigurationProperties props = ConfigurationProperties.getBean(ctx);
-				PROPERTY_DEFAULT_NAMESPACE);
+		defaultNamespace = props.getProperty(PROPERTY_DEFAULT_NAMESPACE);
+		enabled = Boolean.valueOf(props.getProperty(PROPERTY_ENABLE_CACHING));
 	}
 
 	@Override
@@ -102,10 +107,14 @@ public class CachingResponseFilter implements Filter {
 		HttpServletResponse resp = (HttpServletResponse) response;
 
 		/*
-		 * If this request is not for a profile page, or if the individual
+		 * If caching is disabled, if this request is not for a profile page, or
-		 * doesn't appear in the search index, create a basic, cache-neutral
+		 * if the individual doesn't appear in the search index, create a basic,
-		 * response.
+		 * cache-neutral response.
 		 */
+		if (!enabled) {
+			produceBasicResponse(req, resp, chain);
+			return;
+		}
 		String individualUri = figureIndividualUriFromRequest(req);
 		if (individualUri == null) {
 			produceBasicResponse(req, resp, chain);