Expose clientIdentifier generation as a function

java/org/apache/catalina/valves/CrawlerSessionManagerValve.java

@@ -22,6 +22,7 @@
 import java.util.Enumeration;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
 import java.util.regex.Pattern;
 
 import jakarta.servlet.ServletException;
@@ -60,6 +61,8 @@ public class CrawlerSessionManagerValve extends ValveBase {
 
     private boolean isContextAware = true;
 
+    private Function<Request, String> clientIdentifierFunction = this::getClientIdentifier;
+
 
     /**
      * Specifies a default constructor so async support can be configured.
@@ -163,6 +166,14 @@ public void setContextAware(boolean isContextAware) {
         this.isContextAware = isContextAware;
     }
 
+    /**
+     * Specify the clientIdentifier function that will be used to identify unique clients. The default is to use
+     * the client IP address, optionally combined with the host name and context name
+     * @param clientIdentifierFunction
+     */
+    public void setClientIdentifierFunction(Function<Request, String> clientIdentifierFunction) {
+        this.clientIdentifierFunction = clientIdentifierFunction;
+    }
 
     @Override
     protected void initInternal() throws LifecycleException {
@@ -185,7 +196,7 @@ public void invoke(Request request, Response response) throws IOException, Servl
         boolean isBot = false;
         String sessionId = null;
         String clientIp = request.getRemoteAddr();
-        String clientIdentifier = getClientIdentifier(host, request.getContext(), clientIp);
+        String clientIdentifier = clientIdentifierFunction.apply(request);
 
         if (log.isTraceEnabled()) {
             log.trace(request.hashCode() + ": ClientIdentifier=" + clientIdentifier + ", RequestedSessionId=" +
@@ -263,12 +274,12 @@ public void invoke(Request request, Response response) throws IOException, Servl
         }
     }
 
-
-    private String getClientIdentifier(Host host, Context context, String clientIp) {
-        StringBuilder result = new StringBuilder(clientIp);
+    private String getClientIdentifier(Request request) {
+        StringBuilder result = new StringBuilder(request.getRemoteAddr());
         if (isHostAware) {
-            result.append('-').append(host.getName());
+            result.append('-').append(request.getHost().getName());
         }
+        Context context = request.getContext();
         if (isContextAware && context != null) {
             result.append(context.getName());
         }