Added builtin function to test if is logged in based on session inter…

…ceptor instance

core/src/main/java/com/predic8/membrane/core/lang/spel/functions/BuiltInFunctions.java

@@ -14,14 +14,18 @@
 package com.predic8.membrane.core.lang.spel.functions;
 
 import com.predic8.membrane.core.http.Header;
+import com.predic8.membrane.core.interceptor.AbstractInterceptorWithSession;
 import com.predic8.membrane.core.lang.spel.ExchangeEvaluationContext;
 import org.apache.http.auth.AUTH;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.List;
 import java.util.function.Predicate;
 
 import static com.predic8.membrane.core.http.Header.AUTHORIZATION;
 import static com.predic8.membrane.core.interceptor.apikey.ApiKeysInterceptor.SCOPES;
+import static java.util.Objects.requireNonNull;
 import static java.util.Optional.ofNullable;
 
 /**
@@ -33,6 +37,17 @@
  * The ExchangeEvaluationContext provides a specialized Membrane SpEL context, enabling access to the Exchange and other relevant data.
  */
 public class BuiltInFunctions {
+    private static final Logger log = LoggerFactory.getLogger(ExchangeEvaluationContext.class.getName());
+
+    public static boolean isLoggedIn(String beanName, ExchangeEvaluationContext ctx) {
+        try {
+            return ((AbstractInterceptorWithSession) requireNonNull(ctx.getBeanResolver()).resolve(ctx, beanName))
+                    .getSessionManager().getSession(ctx.getExchange()).isVerified();
+        } catch (Exception e) {
+            log.info("Failed to resolve bean with name '" + beanName + "'");
+            return false;
+        }
+    }
 
     public static boolean isBearerAuthorization(ExchangeEvaluationContext ctx) {
         return ctx.getExchange().getRequest().getHeader().contains(AUTHORIZATION)