CAMEL-23543: Centralize and harden Camel* header filtering in DefaultHeaderFilterStrategy

components/camel-aws/camel-aws2-sns/src/main/java/org/apache/camel/component/aws2/sns/Sns2HeaderFilterStrategy.java

@@ -19,15 +19,12 @@
 import org.apache.camel.support.DefaultHeaderFilterStrategy;
 
 public class Sns2HeaderFilterStrategy extends DefaultHeaderFilterStrategy {
+
     public Sns2HeaderFilterStrategy() {
         initialize();
     }
 
     protected void initialize() {
-        setLowerCase(true);
-
-        // filter headers begin with "Camel" or "org.apache.camel"
-        setOutFilterPattern("(breadcrumbId|Camel|org\\.apache\\.camel)[\\.|a-z|A-z|0-9]*");
-        setInFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
+        getOutFilter().add("breadcrumbId");
     }
 }

components/camel-aws/camel-aws2-sqs/src/main/java/org/apache/camel/component/aws2/sqs/Sqs2HeaderFilterStrategy.java

@@ -19,14 +19,12 @@
 import org.apache.camel.support.DefaultHeaderFilterStrategy;
 
 public class Sqs2HeaderFilterStrategy extends DefaultHeaderFilterStrategy {
+
     public Sqs2HeaderFilterStrategy() {
         initialize();
     }
 
     protected void initialize() {
-        setLowerCase(true);
-        // filter headers begin with "Camel" or "org.apache.camel"
-        setOutFilterPattern("(breadcrumbId|Camel|org\\.apache\\.camel)[\\.|a-z|A-z|0-9]*");
-        setInFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
+        getOutFilter().add("breadcrumbId");
     }
 }

components/camel-aws/camel-aws2-sqs/src/test/java/org/apache/camel/component/aws2/sqs/Sqs2HeaderFilterStrategyTest.java

@@ -43,7 +43,6 @@ void inboundAllowsNonCamelHeaders() {
     @Test
     void outboundFiltersCamelAndBreadcrumbHeaders() {
         assertTrue(strategy.applyFilterToCamelHeaders("CamelHttpUri", "value", null));
-        assertTrue(strategy.applyFilterToCamelHeaders("org.apache.camel.internal", "value", null));
         assertTrue(strategy.applyFilterToCamelHeaders("breadcrumbId", "value", null));
     }
 

components/camel-azure/camel-azure-servicebus/src/main/java/org/apache/camel/component/azure/servicebus/ServiceBusHeaderFilterStrategy.java

@@ -37,13 +37,6 @@ public class ServiceBusHeaderFilterStrategy extends DefaultHeaderFilterStrategy
             Date.class,
             UUID.class);
 
-    public ServiceBusHeaderFilterStrategy() {
-        super();
-        setLowerCase(true);
-        setOutFilterStartsWith(DefaultHeaderFilterStrategy.CAMEL_FILTER_STARTS_WITH);
-        setInFilterStartsWith(DefaultHeaderFilterStrategy.CAMEL_FILTER_STARTS_WITH);
-    }
-
     @Override
     public boolean applyFilterToCamelHeaders(String headerName, Object headerValue, Exchange exchange) {
         return headerValue == null || !SUPPORTED_TYPES.contains(headerValue.getClass())

components/camel-coap/src/main/java/org/apache/camel/coap/CoAPEndpoint.java

@@ -45,6 +45,7 @@
 import org.apache.camel.spi.UriParam;
 import org.apache.camel.spi.UriPath;
 import org.apache.camel.support.DefaultEndpoint;
+import org.apache.camel.support.DefaultHeaderFilterStrategy;
 import org.apache.camel.support.jsse.ClientAuthentication;
 import org.apache.camel.support.jsse.KeyManagersParameters;
 import org.apache.camel.support.jsse.SSLContextParameters;
@@ -281,7 +282,7 @@ public void setClient(CoapClient client) {
     @Override
     public HeaderFilterStrategy getHeaderFilterStrategy() {
         if (headerFilterStrategy == null) {
-            headerFilterStrategy = new CoAPHeaderFilterStrategy();
+            headerFilterStrategy = new DefaultHeaderFilterStrategy();
         }
         return headerFilterStrategy;
     }

components/camel-cometd/src/main/java/org/apache/camel/component/cometd/CometdBinding.java

@@ -26,6 +26,7 @@
 import org.apache.camel.Message;
 import org.apache.camel.spi.HeaderFilterStrategy;
 import org.apache.camel.spi.Metadata;
+import org.apache.camel.support.DefaultHeaderFilterStrategy;
 import org.apache.camel.support.DefaultMessage;
 import org.cometd.bayeux.server.ServerChannel;
 import org.cometd.bayeux.server.ServerMessage;
@@ -57,7 +58,7 @@ public CometdBinding(BayeuxServerImpl bayeux) {
     }
 
     public CometdBinding(BayeuxServerImpl bayeux, boolean enableSessionHeader) {
-        this(bayeux, enableSessionHeader, new CometdHeaderFilterStrategy());
+        this(bayeux, enableSessionHeader, new DefaultHeaderFilterStrategy());
     }
 
     public CometdBinding(BayeuxServerImpl bayeux, boolean enableSessionHeader, HeaderFilterStrategy headerFilterStrategy) {

components/camel-cxf/camel-cxf-common/src/main/java/org/apache/camel/component/cxf/common/header/CxfHeaderHelper.java

@@ -130,7 +130,8 @@ public static void propagateCamelToCxf(
 
         camelHeaders.entrySet().forEach(entry -> {
             // Need to make sure the cxf needed header will not be filtered
-            if (strategy.applyFilterToCamelHeaders(entry.getKey(), entry.getValue(), exchange)) {
+            if (strategy.applyFilterToCamelHeaders(entry.getKey(), entry.getValue(), exchange)
+                    && CAMEL_TO_CXF_HEADERS.get(entry.getKey()) == null) {
                 LOG.trace("Drop external header: {}={}", entry.getKey(), entry.getValue());
                 return;
             }

components/camel-cxf/camel-cxf-rest/src/main/java/org/apache/camel/component/cxf/jaxrs/CxfRsHeaderFilterStrategy.java

@@ -26,17 +26,8 @@ public CxfRsHeaderFilterStrategy() {
     }
 
     protected void initialize() {
-
         getOutFilter().add(CxfConstants.OPERATION_NAME.toLowerCase());
 
         getOutFilter().add("Content-Type".toLowerCase());
-        // Support to filter the Content-Type case insensitive
-        setLowerCase(true);
-
-        // filter headers begin with "Camel" or "org.apache.camel"
-        setOutFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
-        setInFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
-
     }
-
 }

components/camel-cxf/camel-cxf-transport/src/main/java/org/apache/camel/component/cxf/transport/header/CxfHeaderFilterStrategy.java

@@ -89,15 +89,9 @@ protected void initialize() {
         // is passed to the other endpoint
         getInFilter().add("content-length".toLowerCase());
 
-        setLowerCase(true);
-
         // initialize message header filter map with default SOAP filter
         messageHeaderFiltersMap = new HashMap<>();
         addToMessageHeaderFilterMap(new SoapMessageHeaderFilter());
-
-        // filter headers begin with "Camel" or "org.apache.camel"
-        setOutFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
-        setInFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
     }
 
     @SuppressWarnings("unchecked")

components/camel-google/camel-google-pubsub/src/main/java/org/apache/camel/component/google/pubsub/GooglePubsubHeaderFilterStrategy.java

@@ -25,9 +25,6 @@ public GooglePubsubHeaderFilterStrategy() {
     }
 
     public GooglePubsubHeaderFilterStrategy(boolean includeAllGoogleProperties) {
-        setLowerCase(true);
-        setOutFilterStartsWith(DefaultHeaderFilterStrategy.CAMEL_FILTER_STARTS_WITH);
-        setInFilterStartsWith(DefaultHeaderFilterStrategy.CAMEL_FILTER_STARTS_WITH);
         // Filter authorization on both directions for security
         getOutFilter().add("authorization");
         getInFilter().add("authorization");

components/camel-http-base/src/main/java/org/apache/camel/http/base/HttpHeaderFilterStrategy.java

@@ -30,13 +30,6 @@ public HttpHeaderFilterStrategy() {
     protected void initialize() {
         final Set<String> outFilter = getOutFilter();
         HttpUtil.addCommonFilters(outFilter);
-
-        setLowerCase(true);
-
-        // filter headers begin with "Camel" or "org.apache.camel"
-        // must ignore case for Http based transports
-        setOutFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
-        setInFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
     }
 
 }

components/camel-http-base/src/main/java/org/apache/camel/http/base/HttpProtocolHeaderFilterStrategy.java

@@ -27,6 +27,10 @@ public HttpProtocolHeaderFilterStrategy() {
 
     // Just add the http headers here
     protected void initialize() {
+        // This strategy filters HTTP protocol headers only; Camel-prefixed headers must not be blocked
+        // so that they survive the request-to-response copy in HttpProducer.copyHeaders.
+        setInFilterStartsWith((String[]) null);
+        setOutFilterStartsWith((String[]) null);
 
         getInFilter().add("content-encoding");
         getInFilter().add("content-language");
@@ -68,7 +72,5 @@ protected void initialize() {
         getInFilter().add("www-authenticate");
 
         HttpUtil.addCommonFilters(getInFilter());
-
-        setLowerCase(true);
     }
 }

components/camel-http-common/src/main/java/org/apache/camel/http/common/HttpHeaderFilterStrategy.java

@@ -33,13 +33,6 @@ public HttpHeaderFilterStrategy() {
     protected void initialize() {
         final Set<String> outFilter = getOutFilter();
         HttpUtil.addCommonFilters(outFilter);
-
-        setLowerCase(true);
-
-        // filter headers begin with "Camel" or "org.apache.camel"
-        // must ignore case for Http based transports
-        setOutFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
-        setInFilterStartsWith(CAMEL_FILTER_STARTS_WITH);
     }
 
 }

components/camel-http-common/src/main/java/org/apache/camel/http/common/HttpProtocolHeaderFilterStrategy.java

@@ -16,5 +16,9 @@
  */
 package org.apache.camel.http.common;
 
+/**
+ * @deprecated use {@link org.apache.camel.http.base.HttpProtocolHeaderFilterStrategy} directly
+ */
+@Deprecated(since = "4.21")
 public class HttpProtocolHeaderFilterStrategy extends org.apache.camel.http.base.HttpProtocolHeaderFilterStrategy {
 }

components/camel-http/src/main/java/org/apache/camel/component/http/HttpProducer.java

@@ -45,9 +45,9 @@
 import org.apache.camel.WrappedFile;
 import org.apache.camel.component.http.helper.HttpMethodHelper;
 import org.apache.camel.http.base.HttpOperationFailedException;
+import org.apache.camel.http.base.HttpProtocolHeaderFilterStrategy;
 import org.apache.camel.http.base.cookie.CookieHandler;
 import org.apache.camel.http.common.HttpHelper;
-import org.apache.camel.http.common.HttpProtocolHeaderFilterStrategy;
 import org.apache.camel.spi.HeaderFilterStrategy;
 import org.apache.camel.support.DefaultProducer;
 import org.apache.camel.support.ExchangeHelper;

components/camel-iggy/src/main/java/org/apache/camel/component/iggy/IggyEndpoint.java

@@ -32,6 +32,7 @@
 import org.apache.camel.spi.UriParam;
 import org.apache.camel.spi.UriPath;
 import org.apache.camel.support.DefaultEndpoint;
+import org.apache.camel.support.DefaultHeaderFilterStrategy;
 import org.apache.iggy.client.blocking.IggyBaseClient;
 import org.apache.iggy.consumergroup.ConsumerGroupDetails;
 import org.apache.iggy.identifier.ConsumerId;
@@ -170,7 +171,7 @@ public ExecutorService createExecutor() {
     @Override
     public HeaderFilterStrategy getHeaderFilterStrategy() {
         if (headerFilterStrategy == null) {
-            headerFilterStrategy = new IggyHeaderFilterStrategy();
+            headerFilterStrategy = new DefaultHeaderFilterStrategy();
         }
         return headerFilterStrategy;
     }