feat(coap-core): Configure custom recognized critical options in CoapServerBuilder (#119)

Author: tuukkateppola

coap-core/src/main/java/com/mbed/coap/packet/BasicHeaderOptions.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2024 java-coap contributors (https://github.com/open-coap/java-coap)
+ * Copyright (C) 2022-2025 java-coap contributors (https://github.com/open-coap/java-coap)
  * Copyright (C) 2011-2021 ARM Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,6 +23,7 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedList;
@@ -139,11 +140,15 @@ public Opaque getCustomOption(Integer optNumber) {
     }
 
     public boolean containsUnrecognisedCriticalOption() {
+        return containsUnrecognisedCriticalOption(Collections.emptySet());
+    }
+
+    public boolean containsUnrecognisedCriticalOption(final Collection<Integer> customOptions) {
         if (unrecognizedOptions == null) {
             return false;
         }
         for (int tp : unrecognizedOptions.keySet()) {
-            if (isCritical(tp)) {
+            if (!customOptions.contains(tp) && isCritical(tp)) {
                 return true;
             }
         }

coap-core/src/main/java/com/mbed/coap/server/CoapServerBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2024 java-coap contributors (https://github.com/open-coap/java-coap)
+ * Copyright (C) 2022-2025 java-coap contributors (https://github.com/open-coap/java-coap)
  * Copyright (C) 2011-2021 ARM Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -56,6 +56,8 @@
 import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.time.Duration;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
@@ -85,6 +87,7 @@ public final class CoapServerBuilder {
     private ObservationsStore observationStore = ObservationsStore.ALWAYS_EMPTY;
     private RequestTagSupplier requestTagSupplier = RequestTagSupplier.createSequential();
     private boolean isTransportLoggingEnabled = true;
+    private Collection<Integer> recognizedCustomOptions = Collections.emptySet();
 
     CoapServerBuilder() {
     }
@@ -228,6 +231,17 @@ public CoapServerBuilder transportLogging(boolean isTransportLoggingEnabled) {
         return this;
     }
 
+    /**
+     * Sets the collection of recognized custom critical CoAP option numbers.
+     *
+     * @param recognizedCustomOptions a collection of integer option numbers to be recognized as custom options
+     * @return this builder instance for method chaining
+     */
+    public CoapServerBuilder recognizedCustomOptions(Collection<Integer> recognizedCustomOptions) {
+        this.recognizedCustomOptions = requireNonNull(recognizedCustomOptions);
+        return this;
+    }
+
     public CoapServer build() {
         CoapTransport realTransport = requireNonNull(this.coapTransport.get(), "Missing transport");
         CoapTransport coapTransport = isTransportLoggingEnabled ? LoggingCoapTransport.wrap(realTransport) : realTransport;
@@ -273,7 +287,7 @@ public CoapServer build() {
                 .andThen(new CoapRequestConverter(midSupplier))
                 .andThen(inboundRequestFilter)
                 .andThen(new RescueFilter())
-                .andThen(new CriticalOptionVerifier())
+                .andThen(new CriticalOptionVerifier(recognizedCustomOptions))
                 .andThen(new BlockWiseIncomingFilter(capabilities(), maxIncomingBlockTransferSize))
                 .andThen(routeFilter)
                 .then(route);

coap-core/src/main/java/com/mbed/coap/server/CriticalOptionVerifier.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2023 java-coap contributors (https://github.com/open-coap/java-coap)
+ * Copyright (C) 2022-2025 java-coap contributors (https://github.com/open-coap/java-coap)
  * Copyright (C) 2011-2021 ARM Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,13 +22,25 @@
 import com.mbed.coap.packet.Code;
 import com.mbed.coap.utils.Filter;
 import com.mbed.coap.utils.Service;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.concurrent.CompletableFuture;
 
 class CriticalOptionVerifier implements Filter.SimpleFilter<CoapRequest, CoapResponse> {
 
+    private final Collection<Integer> recognizedCustomOptions;
+
+    CriticalOptionVerifier() {
+        this.recognizedCustomOptions = Collections.emptySet();
+    }
+
+    CriticalOptionVerifier(final Collection<Integer> recognizedCustomOptions) {
+        this.recognizedCustomOptions = recognizedCustomOptions;
+    }
+
     @Override
     public CompletableFuture<CoapResponse> apply(CoapRequest request, Service<CoapRequest, CoapResponse> service) {
-        if (request.options().containsUnrecognisedCriticalOption()) {
+        if (request.options().containsUnrecognisedCriticalOption(recognizedCustomOptions)) {
             return coapResponse(Code.C402_BAD_OPTION).toFuture();
         }
         return service.apply(request);

coap-core/src/test/java/com/mbed/coap/packet/HeaderOptionsTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2023 java-coap contributors (https://github.com/open-coap/java-coap)
+ * Copyright (C) 2022-2025 java-coap contributors (https://github.com/open-coap/java-coap)
  * Copyright (C) 2011-2021 ARM Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -35,6 +35,7 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Arrays;
+import java.util.Collections;
 import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.Warning;
 import org.junit.jupiter.api.Test;
@@ -422,6 +423,9 @@ public void criticalOptTest() throws Exception {
 
         h.put(1001, Opaque.of("foo"));
         assertTrue(h.containsUnrecognisedCriticalOption());
+
+        h.put(1001, Opaque.of("foo"));
+        assertFalse(h.containsUnrecognisedCriticalOption(Collections.singleton(1001)));
     }
 
     @Test

coap-core/src/test/java/com/mbed/coap/server/CoapServerBuilderTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2024 java-coap contributors (https://github.com/open-coap/java-coap)
+ * Copyright (C) 2022-2025 java-coap contributors (https://github.com/open-coap/java-coap)
  * Copyright (C) 2011-2021 ARM Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -60,6 +60,13 @@ public void shouldFail_whenIllegalTimeoutValue() throws Exception {
         );
     }
 
+    @Test
+    public void shouldFail_whenNullRecognizedCustomOptionsValue() throws Exception {
+        assertThrows(NullPointerException.class, () ->
+                CoapServer.builder().recognizedCustomOptions(null)
+        );
+    }
+
     @Test
     public void shouldReuseBuilder() throws Exception {
         CoapServer server = new CoapServerBuilder()

coap-core/src/test/java/com/mbed/coap/server/CriticalOptionVerifierTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2023 java-coap contributors (https://github.com/open-coap/java-coap)
+ * Copyright (C) 2022-2025 java-coap contributors (https://github.com/open-coap/java-coap)
  * SPDX-License-Identifier: Apache-2.0
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,19 +22,33 @@
 import com.mbed.coap.packet.CoapResponse;
 import com.mbed.coap.packet.Code;
 import com.mbed.coap.packet.Opaque;
+import com.mbed.coap.utils.Service;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import org.junit.jupiter.api.Test;
 
 class CriticalOptionVerifierTest {
 
-    private final CriticalOptionVerifier filter = new CriticalOptionVerifier();
-
     @Test
     void shouldReturnBadOptionWhenUnrecognizedCriticalOption() {
+        final CriticalOptionVerifier filter = new CriticalOptionVerifier();
+
         CoapRequest req = get("/test").options(o -> o.custom(1001, Opaque.of("foo"))).build();
 
         CompletableFuture<CoapResponse> resp = filter.apply(req, null);
 
         assertEquals(of(Code.C402_BAD_OPTION), resp.join());
     }
-}
+
+    @Test
+    void shouldReturnNotBadOptionWhenCustomCriticalOption() {
+        final CriticalOptionVerifier filter = new CriticalOptionVerifier(new HashSet<Integer>() {{ add(1001); }});
+
+        CoapRequest req = get("/test").options(o -> o.custom(1001, Opaque.of("foo"))).build();
+
+        CompletableFuture<CoapResponse> resp = filter.apply(req, coapRequest -> CompletableFuture.completedFuture(of(Code.C205_CONTENT)));
+
+        assertEquals(of(Code.C205_CONTENT), resp.join());
+    }
+}

coap-tcp/src/main/java/com/mbed/coap/server/CoapServerBuilderForTcp.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022-2024 java-coap contributors (https://github.com/open-coap/java-coap)
+ * Copyright (C) 2022-2025 java-coap contributors (https://github.com/open-coap/java-coap)
  * Copyright (C) 2011-2021 ARM Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -43,6 +43,8 @@
 import com.mbed.coap.utils.Service;
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.Objects;
 import java.util.function.Function;
 
@@ -59,6 +61,7 @@ public class CoapServerBuilderForTcp {
     private NotificationsReceiver notificationsReceiver = NotificationsReceiver.REJECT_ALL;
     private ObservationsStore observationsStore = ObservationsStore.ALWAYS_EMPTY;
     private Boolean isTransportLoggingEnabled = true;
+    private Collection<Integer> recognizedCustomOptions = Collections.emptySet();
 
     CoapServerBuilderForTcp() {
         csmStorage = new CapabilitiesStorageImpl();
@@ -135,6 +138,17 @@ public CoapServerBuilderForTcp transportLogging(Boolean transportLogging) {
         return this;
     }
 
+    /**
+     * Sets the collection of recognized custom critical CoAP option numbers.
+     *
+     * @param recognizedCustomOptions a collection of integer option numbers to be recognized as custom options
+     * @return this builder instance for method chaining
+     */
+    public CoapServerBuilderForTcp recognizedCustomOptions(Collection<Integer> recognizedCustomOptions) {
+        this.recognizedCustomOptions = requireNonNull(recognizedCustomOptions);
+        return this;
+    }
+
     public CoapClient buildClient(InetSocketAddress target) throws IOException {
         return CoapClient.create(target, build().start(), r -> r.getCode() == Code.C703_PONG);
     }
@@ -151,7 +165,7 @@ public CoapServer build() {
 
         // INBOUND
         Service<CoapRequest, CoapResponse> inboundService = new RescueFilter()
-                .andThenIf(hasRoute(), new CriticalOptionVerifier())
+                .andThenIf(hasRoute(), new CriticalOptionVerifier(recognizedCustomOptions))
                 .andThenIf(hasRoute(), new BlockWiseIncomingFilter(capabilities(), maxIncomingBlockTransferSize))
                 .andThen(routeFilter)
                 .then(route);