Allow customizing ObjectReader via @CustomDeserialization in Resteasy

docs/src/main/asciidoc/resteasy-reactive.adoc

@@ -1425,12 +1425,12 @@ public User userPrivate() {
 When the result the `userPublic` method is serialized, the `id` field will not be contained in the response as the `Public` view does not include it.
 The result of `userPrivate` however will include the `id` as expected when serialized.
 
-===== Completely customized per method serialization
+===== Completely customized per method serialization/deserialization
 
-There are times when you need to completely customize the serialization of a POJO on a per Jakarta REST method basis. For such use cases, the `@io.quarkus.resteasy.reactive.jackson.CustomSerialization` annotation
-is a great tool, as it allows you to configure a per-method `com.fasterxml.jackson.databind.ObjectWriter` which can be configured at will.
+There are times when you need to completely customize the serialization/deserialization of a POJO on a per Jakarta REST method basis. For such use cases, the `@io.quarkus.resteasy.reactive.jackson.CustomSerialization` and `@io.quarkus.resteasy.reactive.jackson.CustomDeserialization` annotations.
+is a great tool, as it allows you to configure a per-method `com.fasterxml.jackson.databind.ObjectWriter`/`com.fasterxml.jackson.databind.ObjectReader` which can be configured at will.
 
-Here is an example use case:
+Here is an example use case to customize the `com.fasterxml.jackson.databind.ObjectWriter`:
 
 [source,java]
 ----
@@ -1459,6 +1459,31 @@ Essentially what this class does is force Jackson to not include quotes in the f
 
 It is important to note that this customization is only performed for the serialization of the Jakarta REST methods that use `@CustomSerialization(UnquotedFields.class)`.
 
+Following the previous example, let's now customize the `com.fasterxml.jackson.databind.ObjectReader` to read JSON requests with unquoted field names:
+
+[source,java]
+----
+@CustomDeserialization(SupportUnquotedFields.class)
+@POST
+@Path("/use-of-custom-deserializer")
+public void useOfCustomSerializer(User request) {
+    // ...
+}
+----
+
+where `SupportUnquotedFields` is a `BiFunction` defined as so:
+
+[source,java]
+----
+public static class SupportUnquotedFields implements BiFunction<ObjectMapper, Type, ObjectReader> {
+
+    @Override
+    public ObjectReader apply(ObjectMapper objectMapper, Type type) {
+        return objectMapper.reader().with(JsonReadFeature.ALLOW_UNQUOTED_FIELD_NAMES);
+    }
+}
+----
+
 === XML serialisation
 
 [[xml]]

extensions/resteasy-reactive/quarkus-resteasy-reactive-jackson/deployment/src/main/java/io/quarkus/resteasy/reactive/jackson/deployment/processor/JacksonFeatureBuildItem.java

@@ -19,6 +19,7 @@ public Feature getFeature() {
 
     public enum Feature {
         JSON_VIEW,
-        CUSTOM_SERIALIZATION
+        CUSTOM_SERIALIZATION,
+        CUSTOM_DESERIALIZATION
     }
 }

extensions/resteasy-reactive/quarkus-resteasy-reactive-jackson/deployment/src/main/java/io/quarkus/resteasy/reactive/jackson/deployment/processor/ResteasyReactiveJacksonProcessor.java

@@ -45,6 +45,7 @@
 import io.quarkus.resteasy.reactive.common.deployment.JaxRsResourceIndexBuildItem;
 import io.quarkus.resteasy.reactive.common.deployment.ResourceScanningResultBuildItem;
 import io.quarkus.resteasy.reactive.common.deployment.ServerDefaultProducesHandlerBuildItem;
+import io.quarkus.resteasy.reactive.jackson.CustomDeserialization;
 import io.quarkus.resteasy.reactive.jackson.CustomSerialization;
 import io.quarkus.resteasy.reactive.jackson.DisableSecureSerialization;
 import io.quarkus.resteasy.reactive.jackson.EnableSecureSerialization;
@@ -77,6 +78,7 @@ public class ResteasyReactiveJacksonProcessor {
 
     private static final DotName JSON_VIEW = DotName.createSimple(JsonView.class.getName());
     private static final DotName CUSTOM_SERIALIZATION = DotName.createSimple(CustomSerialization.class.getName());
+    private static final DotName CUSTOM_DESERIALIZATION = DotName.createSimple(CustomDeserialization.class.getName());
     private static final DotName SECURE_FIELD = DotName.createSimple(SecureField.class.getName());
     private static final DotName DISABLE_SECURE_SERIALIZATION = DotName
             .createSimple(DisableSecureSerialization.class.getName());
@@ -265,6 +267,36 @@ void handleJsonAnnotations(Optional<ResourceScanningResultBuildItem> resourceSca
                             biFunctionType.name().toString());
                 }
             }
+            if (resourceClass.annotationsMap().containsKey(CUSTOM_DESERIALIZATION)) {
+                jacksonFeatures.add(JacksonFeatureBuildItem.Feature.CUSTOM_DESERIALIZATION);
+                for (AnnotationInstance instance : resourceClass.annotationsMap().get(CUSTOM_DESERIALIZATION)) {
+                    AnnotationValue annotationValue = instance.value();
+                    if (annotationValue == null) {
+                        continue;
+                    }
+                    if (instance.target().kind() != AnnotationTarget.Kind.METHOD) {
+                        continue;
+                    }
+                    Type biFunctionType = annotationValue.asClass();
+                    if (biFunctionType == null) {
+                        continue;
+                    }
+                    ClassInfo biFunctionClassInfo = index.getIndex().getClassByName(biFunctionType.name());
+                    if (biFunctionClassInfo == null) {
+                        // be lenient
+                    } else {
+                        if (!biFunctionClassInfo.hasNoArgsConstructor()) {
+                            throw new IllegalArgumentException(
+                                    "Class '" + biFunctionClassInfo.name() + "' must contain a no-args constructor");
+                        }
+                    }
+                    reflectiveClassProducer.produce(
+                            ReflectiveClassBuildItem.builder(biFunctionType.name().toString())
+                                    .build());
+                    recorder.recordCustomDeserialization(getMethodId(instance.target().asMethod()),
+                            biFunctionType.name().toString());
+                }
+            }
         }
 
         for (ResourceMethodCustomSerializationBuildItem bi : resourceMethodCustomSerializationBuildItems) {

extensions/resteasy-reactive/quarkus-resteasy-reactive-jackson/deployment/src/test/java/io/quarkus/resteasy/reactive/jackson/deployment/test/SimpleJsonResource.java

@@ -24,10 +24,13 @@
 import org.jboss.resteasy.reactive.server.ServerExceptionMapper;
 
 import com.fasterxml.jackson.annotation.JsonView;
+import com.fasterxml.jackson.core.json.JsonReadFeature;
 import com.fasterxml.jackson.core.json.JsonWriteFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.ObjectReader;
 import com.fasterxml.jackson.databind.ObjectWriter;
 
+import io.quarkus.resteasy.reactive.jackson.CustomDeserialization;
 import io.quarkus.resteasy.reactive.jackson.CustomSerialization;
 import io.quarkus.resteasy.reactive.jackson.DisableSecureSerialization;
 import io.quarkus.resteasy.reactive.jackson.EnableSecureSerialization;
@@ -56,13 +59,20 @@ public Person getPerson() {
         return person;
     }
 
-    @CustomSerialization(UnquotedFieldsPersonBiFunction.class)
+    @CustomSerialization(UnquotedFieldsPersonSerialization.class)
     @GET
     @Path("custom-serialized-person")
     public Person getCustomSerializedPerson() {
         return getPerson();
     }
 
+    @CustomDeserialization(UnquotedFieldsPersonDeserialization.class)
+    @POST
+    @Path("custom-deserialized-person")
+    public Person echoCustomDeserializedPerson(Person request) {
+        return request;
+    }
+
     @EnableSecureSerialization
     @GET
     @Path("secure-person")
@@ -180,7 +190,8 @@ public List<Person> getPeople(List<Person> people) {
         return reversed;
     }
 
-    @CustomSerialization(UnquotedFieldsPersonBiFunction.class)
+    @CustomDeserialization(UnquotedFieldsPersonDeserialization.class)
+    @CustomSerialization(UnquotedFieldsPersonSerialization.class)
     @POST
     @Path("/custom-serialized-people")
     @Consumes(MediaType.APPLICATION_JSON)
@@ -261,7 +272,7 @@ public User userWithPrivateView() {
         return testUser();
     }
 
-    @CustomSerialization(UnquotedFieldsPersonBiFunction.class)
+    @CustomSerialization(UnquotedFieldsPersonSerialization.class)
     @GET
     @Path("/invalid-use-of-custom-serializer")
     public User invalidUseOfCustomSerializer() {
@@ -308,11 +319,11 @@ public String genericInputTest(DataItem<Item> item) {
         return item.getContent().getName();
     }
 
-    public static class UnquotedFieldsPersonBiFunction implements BiFunction<ObjectMapper, Type, ObjectWriter> {
+    public static class UnquotedFieldsPersonSerialization implements BiFunction<ObjectMapper, Type, ObjectWriter> {
 
         public static final AtomicInteger count = new AtomicInteger();
 
-        public UnquotedFieldsPersonBiFunction() {
+        public UnquotedFieldsPersonSerialization() {
             count.incrementAndGet();
         }
 
@@ -328,4 +339,24 @@ public ObjectWriter apply(ObjectMapper objectMapper, Type type) {
         }
     }
 
+    public static class UnquotedFieldsPersonDeserialization implements BiFunction<ObjectMapper, Type, ObjectReader> {
+
+        public static final AtomicInteger count = new AtomicInteger();
+
+        public UnquotedFieldsPersonDeserialization() {
+            count.incrementAndGet();
+        }
+
+        @Override
+        public ObjectReader apply(ObjectMapper objectMapper, Type type) {
+            if (type instanceof ParameterizedType) {
+                type = ((ParameterizedType) type).getActualTypeArguments()[0];
+            }
+            if (!type.getTypeName().equals(Person.class.getName())) {
+                throw new IllegalArgumentException("Only Person type can be handled");
+            }
+            return objectMapper.reader().with(JsonReadFeature.ALLOW_UNQUOTED_FIELD_NAMES);
+        }
+    }
+
 }

extensions/resteasy-reactive/quarkus-resteasy-reactive-jackson/deployment/src/test/java/io/quarkus/resteasy/reactive/jackson/deployment/test/SimpleJsonTest.java

@@ -248,7 +248,7 @@ public void testJsonMulti() {
 
     @Test
     public void testCustomSerialization() {
-        assertEquals(0, SimpleJsonResource.UnquotedFieldsPersonBiFunction.count.intValue());
+        assertEquals(0, SimpleJsonResource.UnquotedFieldsPersonSerialization.count.intValue());
 
         // assert that we get a proper response
         // we can't use json-path to assert because the returned string is not proper json as it does not have quotes around the field names
@@ -261,7 +261,7 @@ public void testCustomSerialization() {
                 .body(containsString("Bob"))
                 .body(containsString("Builder"));
         // assert that our bi-function was created
-        assertEquals(1, SimpleJsonResource.UnquotedFieldsPersonBiFunction.count.intValue());
+        assertEquals(1, SimpleJsonResource.UnquotedFieldsPersonSerialization.count.intValue());
 
         // assert with a list of people
         RestAssured
@@ -279,7 +279,7 @@ public void testCustomSerialization() {
                 .body(containsString("Bob2"))
                 .body(containsString("Builder2"));
         // assert that another instance of our bi-function was created as a different resource method was used
-        assertEquals(2, SimpleJsonResource.UnquotedFieldsPersonBiFunction.count.intValue());
+        assertEquals(2, SimpleJsonResource.UnquotedFieldsPersonSerialization.count.intValue());
 
         RestAssured.get("/simple/custom-serialized-person")
                 .then()
@@ -294,13 +294,59 @@ public void testCustomSerialization() {
                 .statusCode(200)
                 .contentType("application/json");
         // assert that the instances were re-used as we simply invoked methods that should have already created their object writers
-        assertEquals(2, SimpleJsonResource.UnquotedFieldsPersonBiFunction.count.intValue());
+        assertEquals(2, SimpleJsonResource.UnquotedFieldsPersonSerialization.count.intValue());
 
         RestAssured.get("/simple/invalid-use-of-custom-serializer")
                 .then()
                 .statusCode(500);
         // a new instance should have been created
-        assertEquals(3, SimpleJsonResource.UnquotedFieldsPersonBiFunction.count.intValue());
+        assertEquals(3, SimpleJsonResource.UnquotedFieldsPersonSerialization.count.intValue());
+    }
+
+    @Test
+    public void testCustomDeserialization() {
+        int currentCounter = SimpleJsonResource.UnquotedFieldsPersonDeserialization.count.intValue();
+
+        // assert that the reader support the unquoted fields (because we have used a custom object reader
+        // via `@CustomDeserialization`
+        Person actual = RestAssured.given()
+                .body("{first: \"Hello\", last: \"Deserialization\"}")
+                .contentType("application/json; charset=utf-8")
+                .post("/simple/custom-deserialized-person")
+                .then()
+                .statusCode(200)
+                .contentType("application/json")
+                .header("transfer-encoding", nullValue())
+                .header("content-length", notNullValue())
+                .extract().as(Person.class);
+        assertEquals("Hello", actual.getFirst());
+        assertEquals("Deserialization", actual.getLast());
+        assertEquals(currentCounter + 1, SimpleJsonResource.UnquotedFieldsPersonDeserialization.count.intValue());
+
+        // assert that the instances were re-used as we simply invoked methods that should have already created their object readers
+        RestAssured.given()
+                .body("{first: \"Hello\", last: \"Deserialization\"}")
+                .contentType("application/json; charset=utf-8")
+                .post("/simple/custom-deserialized-person")
+                .then()
+                .statusCode(200);
+        assertEquals(currentCounter + 1, SimpleJsonResource.UnquotedFieldsPersonDeserialization.count.intValue());
+
+        // assert with a list of people
+        RestAssured
+                .with()
+                .body("[{first: \"Bob\", last: \"Builder\"}, {first: \"Bob2\", last: \"Builder2\"}]")
+                .contentType("application/json; charset=utf-8")
+                .post("/simple/custom-serialized-people")
+                .then()
+                .statusCode(200)
+                .contentType("application/json")
+                .header("transfer-encoding", nullValue())
+                .header("content-length", notNullValue())
+                .body(containsString("Bob"))
+                .body(containsString("Builder"))
+                .body(containsString("Bob2"))
+                .body(containsString("Builder2"));
     }
 
     @Test

extensions/resteasy-reactive/quarkus-resteasy-reactive-jackson/runtime/src/main/java/io/quarkus/resteasy/reactive/jackson/CustomDeserialization.java

@@ -0,0 +1,43 @@
+package io.quarkus.resteasy.reactive.jackson;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.lang.reflect.Type;
+import java.util.function.BiFunction;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.ObjectReader;
+
+import io.smallrye.common.annotation.Experimental;
+
+/**
+ * Annotation that can be used on RESTEasy Reactive Resource method to allow users to configure Jackson deserialization
+ * for that method only, without affecting the global Jackson configuration.
+ */
+@Experimental(value = "Remains to be determined if this is the best possible API for users to configure per Resource Method Deserialization")
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.METHOD })
+public @interface CustomDeserialization {
+
+    /**
+     * A {@code BiFunction} that converts the global {@code ObjectMapper} and type for which a custom {@code ObjectReader} is
+     * needed
+     * (this type will be a generic type if the method returns such a generic type) and returns the instance of the custom
+     * {@code ObjectReader}.
+     * <p>
+     * Quarkus will construct one instance of this {@code BiFunction} for each JAX-RS resource method that is annotated with
+     * {@code CustomDeserialization} and once an instance is created it will be cached for subsequent usage by that resource
+     * method.
+     * <p>
+     * The {@code BiFunction} MUST contain a no-args constructor.
+     * <p>
+     * Furthermore, it is advisable that it contains no state that is updated outside
+     * its constructor.
+     * <p>
+     * Finally and most importantly, the {@code ObjectMapper} should NEVER be changed any way as it is the global ObjectMapper
+     * that is accessible to the entire Quarkus application.
+     */
+    Class<? extends BiFunction<ObjectMapper, Type, ObjectReader>> value();
+}

extensions/resteasy-reactive/quarkus-resteasy-reactive-jackson/runtime/src/main/java/io/quarkus/resteasy/reactive/jackson/runtime/ResteasyReactiveServerJacksonRecorder.java

@@ -6,6 +6,7 @@
 import java.util.function.BiFunction;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.ObjectReader;
 import com.fasterxml.jackson.databind.ObjectWriter;
 
 import io.quarkus.runtime.ShutdownContext;
@@ -16,6 +17,7 @@ public class ResteasyReactiveServerJacksonRecorder {
 
     private static final Map<String, Class<?>> jsonViewMap = new HashMap<>();
     private static final Map<String, Class<?>> customSerializationMap = new HashMap<>();
+    private static final Map<String, Class<?>> customDeserializationMap = new HashMap<>();
 
     public void recordJsonView(String methodId, String className) {
         jsonViewMap.put(methodId, loadClass(className));
@@ -25,12 +27,17 @@ public void recordCustomSerialization(String methodId, String className) {
         customSerializationMap.put(methodId, loadClass(className));
     }
 
+    public void recordCustomDeserialization(String methodId, String className) {
+        customDeserializationMap.put(methodId, loadClass(className));
+    }
+
     public void configureShutdown(ShutdownContext shutdownContext) {
         shutdownContext.addShutdownTask(new Runnable() {
             @Override
             public void run() {
                 jsonViewMap.clear();
                 customSerializationMap.clear();
+                customDeserializationMap.clear();
             }
         });
     }
@@ -44,6 +51,12 @@ public static Class<? extends BiFunction<ObjectMapper, Type, ObjectWriter>> cust
         return (Class<? extends BiFunction<ObjectMapper, Type, ObjectWriter>>) customSerializationMap.get(methodId);
     }
 
+    @SuppressWarnings("unchecked")
+    public static Class<? extends BiFunction<ObjectMapper, Type, ObjectReader>> customDeserializationForMethod(
+            String methodId) {
+        return (Class<? extends BiFunction<ObjectMapper, Type, ObjectReader>>) customDeserializationMap.get(methodId);
+    }
+
     private Class<?> loadClass(String className) {
         try {
             return Thread.currentThread().getContextClassLoader().loadClass(className);