Feature/httpcache responseheader exclusion (#1905)

* Add excluded response headers to http cache config

bundle/src/main/java/com/adobe/acs/commons/httpcache/config/HttpCacheConfig.java

@@ -25,6 +25,7 @@
 import com.adobe.acs.commons.httpcache.keys.CacheKey;
 import org.apache.sling.api.SlingHttpServletRequest;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.regex.Pattern;
 
@@ -37,7 +38,7 @@
 @ProviderType
 public interface HttpCacheConfig {
 
-    public enum FilterScope {
+    enum FilterScope {
         REQUEST,
         INCLUDE
     }
@@ -77,6 +78,15 @@ public enum FilterScope {
      */
     List<Pattern> getJCRInvalidationPathPatterns();
 
+    /**
+     * Get a list of headers (as regex pattern) that should NOT be put in the cached response, to be served to the output.
+     * This is useful for example with systems that put a login cookie in each response.
+     * @return
+     */
+    default List<Pattern> getExcludedResponseHeaderPatterns() {
+        return Collections.emptyList();
+    }
+
     /**
      * Determine if this cache config is applicable for the given request. Calls <code>HttpCacheConfigExtension
      * .accept()</code> for providing share of control to the custom code.

bundle/src/main/java/com/adobe/acs/commons/httpcache/config/impl/HttpCacheConfigImpl.java

@@ -28,6 +28,7 @@
 import com.adobe.acs.commons.httpcache.keys.CacheKeyFactory;
 import com.adobe.acs.commons.httpcache.store.HttpCacheStore;
 import com.adobe.acs.commons.httpcache.util.UserUtils;
+import com.adobe.acs.commons.util.ParameterUtil;
 import org.apache.commons.collections.CollectionUtils;
 import org.apache.commons.lang.StringUtils;
 import org.apache.felix.scr.annotations.Activate;
@@ -216,6 +217,15 @@ public class HttpCacheConfigImpl implements HttpCacheConfig {
     static final String PROP_CACHE_HANDLING_RULES_PID = "httpcache.config.cache-handling-rules.pid";
     private List<String> cacheHandlingRulesPid;
 
+
+
+    @Property(label = "Config-specific Excluded Response headers",
+            description = "List of header keys (as regex) that should NOT be put in the cached response, to be served to the output.",
+            unbounded = PropertyUnbounded.ARRAY
+    )
+    static final String PROP_RESPONSE_HEADER_EXCLUSIONS = "httpcache.config.excluded.response.headers";
+    private List<Pattern> responseHeaderExclusions;
+
     @Property(label = "Expiry on create",
         description = "Specifies a custom expiry on create. Overrules the global expiry, unless the value is 0.")
     static final String PROP_EXPIRY_ON_CREATE = "httpcache.config.expiry.on.create";
@@ -249,6 +259,9 @@ protected void activate(Map<String, Object> configs) {
                 String[]{}));
         requestUriPatternsAsRegEx = compileToPatterns(requestUriPatterns);
 
+        responseHeaderExclusions = ParameterUtil.toPatterns(PropertiesUtil.toStringArray(configs.get(PROP_RESPONSE_HEADER_EXCLUSIONS), new String[]{}));
+
+
         // Request URIs - Blacklisted.
         blacklistedRequestUriPatterns = Arrays.asList(PropertiesUtil.toStringArray(configs
                 .get(PROP_BLACKLISTED_REQUEST_URI_PATTERNS), new String[]{}));
@@ -452,4 +465,9 @@ public boolean acceptsRule(String servicePid) {
     public FilterScope getFilterScope() {
         return this.filterScope;
     }
+
+    @Override
+    public List<Pattern> getExcludedResponseHeaderPatterns() {
+        return responseHeaderExclusions;
+    }
 }

bundle/src/main/java/com/adobe/acs/commons/httpcache/config/package-info.java

@@ -18,6 +18,6 @@
  * #L%
  */
 
-@org.osgi.annotation.versioning.Version("2.2.0")
+@org.osgi.annotation.versioning.Version("2.3.0")
 package com.adobe.acs.commons.httpcache.config;
 

bundle/src/main/java/com/adobe/acs/commons/httpcache/engine/CacheContent.java

@@ -28,6 +28,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Represents response content to be cached.
@@ -41,7 +42,7 @@ public class CacheContent {
     /** Response content type */
     private String contentType;
     /** Response headers */
-    private Map<String, List<String>> headers = new HashMap<String, List<String>>();
+    private Map<String, List<String>> headers = new HashMap<>();
     /** Response content as input stream */
     private InputStream dataInputStream;
     /** Temp sink attached to this cache content */
@@ -132,24 +133,37 @@ public CacheContent() {
      * Construct from the custom servlet response wrapper..
      *
      * @param responseWrapper
+     * @deprecated Use build(HttpCacheServletResponseWrapper responseWrapper,int status, String charEncoding, String contentType, Map<String, List<String>> headers) throws HttpCacheDataStreamException
      * @return
      */
+    @Deprecated
     public CacheContent build(HttpCacheServletResponseWrapper responseWrapper) throws HttpCacheDataStreamException {
-        this.status = responseWrapper.getStatus();
+          // Extracting HTTP Response Header Names and Values
+        Map<String, List<String>> extractedHeaders = responseWrapper.getHeaderNames().stream().collect(
+                        Collectors.toMap(headerName -> headerName, headerName ->
+                            new ArrayList<>(responseWrapper.getHeaders(headerName)
+                        )
+        ));
+
+        return build(responseWrapper, responseWrapper.getStatus(), responseWrapper.getCharacterEncoding(), responseWrapper. getContentType(), extractedHeaders);
+    }
+
+    /**
+     * Construct from the custom servlet response wrapper..
+     *
+     * @param responseWrapper
+     * @param headers
+     * @return
+     */
+    public CacheContent build(HttpCacheServletResponseWrapper responseWrapper,int status, String charEncoding, String contentType, Map<String, List<String>> headers) throws HttpCacheDataStreamException {
+        this.status = status;
 
         // Extract information from response and populate state of the instance.
-        this.charEncoding = responseWrapper.getCharacterEncoding();
-        this.contentType = responseWrapper.getContentType();
+        this.charEncoding = charEncoding;
+        this.contentType = contentType;
 
         // Extracting header K,V.
-        List<String> headerNames = new ArrayList<String>();
-
-        headerNames.addAll(responseWrapper.getHeaderNames());
-        for (String headerName: headerNames) {
-            List<String> values = new ArrayList<String>();
-            values.addAll(responseWrapper.getHeaders(headerName));
-            headers.put(headerName, values);
-        }
+        this.headers.putAll(headers);
 
         // Get hold of the temp sink.
         this.tempSink = responseWrapper.getTempSink();