Progress on implementing serialization

Signed-off-by: Francesco Guardiani <francescoguard@gmail.com>

api/src/main/java/io/cloudevents/format/EventFormatProvider.java

@@ -16,7 +16,6 @@ public final class EventFormatProvider {
 
     private HashMap<String, EventFormat> formats;
 
-    //TODO register stuff with SPI
     private EventFormatProvider() {
         this.formats = new HashMap<>();
 

api/src/main/java/io/cloudevents/impl/CloudEventImpl.java

@@ -7,7 +7,7 @@ import io.cloudevents.message.*;
 
 import java.util.*;
 
-public final class CloudEventImpl implements CloudEvent, BinaryMessage {
+public final class CloudEventImpl implements CloudEvent, BinaryMessage, BinaryMessageExtensions {
 
     private final AttributesInternal attributes;
     private final byte[] data;
@@ -71,10 +71,7 @@ public final class CloudEventImpl implements CloudEvent, BinaryMessage {
     }
 
     @Override
-    public <T extends BinaryMessageVisitor<V>, V> V visit(BinaryMessageVisitorFactory<T, V> visitorFactory) throws MessageVisitException, IllegalStateException {
+    public void visitExtensions(BinaryMessageExtensionsVisitor visitor) throws MessageVisitException {
-        BinaryMessageVisitor<V> visitor = visitorFactory.createBinaryMessageVisitor(this.attributes.getSpecVersion());
-        this.attributes.visit(visitor);
-
         // TODO to be improved
         for (Map.Entry<String, Object> entry : this.extensions.entrySet()) {
             if (entry.getValue() instanceof String) {
@@ -88,6 +85,13 @@ public final class CloudEventImpl implements CloudEvent, BinaryMessage {
                 throw new IllegalStateException("Illegal value inside extensions map: " + entry);
             }
         }
+    }
+
+    @Override
+    public <T extends BinaryMessageVisitor<V>, V> V visit(BinaryMessageVisitorFactory<T, V> visitorFactory) throws MessageVisitException, IllegalStateException {
+        BinaryMessageVisitor<V> visitor = visitorFactory.createBinaryMessageVisitor(this.attributes.getSpecVersion());
+        this.attributes.visitAttributes(visitor);
+        this.visitExtensions(visitor);
 
         if (this.data != null) {
             visitor.setBody(this.data);

api/src/main/java/io/cloudevents/message/BinaryMessageAttributes.java

@@ -3,10 +3,9 @@ package io.cloudevents.message;
 public interface BinaryMessageAttributes {
 
     /**
-     *
      * @param visitor
      * @throws MessageVisitException
      */
-    void visit(BinaryMessageAttributesVisitor visitor) throws MessageVisitException;
+    void visitAttributes(BinaryMessageAttributesVisitor visitor) throws MessageVisitException;
 
 }

api/src/main/java/io/cloudevents/message/BinaryMessageAttributesVisitor.java

@@ -5,6 +5,7 @@ import io.cloudevents.types.Time;
 import java.net.URI;
 import java.time.ZonedDateTime;
 
+@FunctionalInterface
 public interface BinaryMessageAttributesVisitor {
 
     void setAttribute(String name, String value) throws MessageVisitException;

api/src/main/java/io/cloudevents/message/BinaryMessageExtensions.java

@@ -0,0 +1,11 @@
+package io.cloudevents.message;
+
+public interface BinaryMessageExtensions {
+
+    /**
+     * @param visitor
+     * @throws MessageVisitException
+     */
+    void visitExtensions(BinaryMessageExtensionsVisitor visitor) throws MessageVisitException;
+
+}

api/src/main/java/io/cloudevents/message/BinaryMessageExtensionsVisitor.java

@@ -1,5 +1,6 @@
 package io.cloudevents.message;
 
+@FunctionalInterface
 public interface BinaryMessageExtensionsVisitor {
 
     void setExtension(String name, String value) throws MessageVisitException;

api/src/main/java/io/cloudevents/v03/AttributesImpl.java

@@ -93,7 +93,7 @@ public final class AttributesImpl implements AttributesInternal {
     }
 
     @Override
-    public void visit(BinaryMessageAttributesVisitor visitor) throws MessageVisitException {
+    public void visitAttributes(BinaryMessageAttributesVisitor visitor) throws MessageVisitException {
         visitor.setAttribute(
             ContextAttributes.ID.name().toLowerCase(),
             this.id

api/src/main/java/io/cloudevents/v1/AttributesImpl.java

@@ -108,7 +108,7 @@ public final class AttributesImpl implements AttributesInternal {
     }
 
     @Override
-    public void visit(BinaryMessageAttributesVisitor visitor) throws MessageVisitException {
+    public void visitAttributes(BinaryMessageAttributesVisitor visitor) throws MessageVisitException {
         visitor.setAttribute(
             ContextAttributes.ID.name().toLowerCase(),
             this.id

formats/json-jackson/src/main/java/io/cloudevents/format/json/CloudEventSerializer.java

@@ -1,23 +1,128 @@
 package io.cloudevents.format.json;
 
 import com.fasterxml.jackson.core.JsonGenerator;
-import com.fasterxml.jackson.databind.JsonSerializer;
 import com.fasterxml.jackson.databind.SerializerProvider;
 import com.fasterxml.jackson.databind.ser.std.StdSerializer;
 import io.cloudevents.CloudEvent;
+import io.cloudevents.impl.AttributesInternal;
+import io.cloudevents.impl.CloudEventImpl;
+import io.cloudevents.message.BinaryMessageAttributesVisitor;
+import io.cloudevents.message.BinaryMessageExtensionsVisitor;
+import io.cloudevents.message.MessageVisitException;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Optional;
 
 public class CloudEventSerializer extends StdSerializer<CloudEvent> {
     protected CloudEventSerializer() {
         super(CloudEvent.class);
     }
 
+    private static class AttributesSerializer implements BinaryMessageAttributesVisitor {
+
+        private JsonGenerator gen;
+
+        public AttributesSerializer(JsonGenerator gen) {
+            this.gen = gen;
+        }
+
+        @Override
+        public void setAttribute(String name, String value) throws MessageVisitException {
+            try {
+                gen.writeStringField(name, value);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
+    private static class ExtensionsSerializer implements BinaryMessageExtensionsVisitor {
+
+        private JsonGenerator gen;
+        private SerializerProvider provider;
+
+        public ExtensionsSerializer(JsonGenerator gen, SerializerProvider provider) {
+            this.gen = gen;
+            this.provider = provider;
+        }
+
+        @Override
+        public void setExtension(String name, String value) throws MessageVisitException {
+            try {
+                gen.writeStringField(name, value);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+        @Override
+        public void setExtension(String name, Number value) throws MessageVisitException {
+            try {
+                gen.writeFieldName(name);
+                provider.findValueSerializer(value.getClass()).serialize(value, gen, provider);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+        @Override
+        public void setExtension(String name, Boolean value) throws MessageVisitException {
+            try {
+                gen.writeBooleanField(name, value);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
     @Override
     public void serialize(CloudEvent value, JsonGenerator gen, SerializerProvider provider) throws IOException {
-        JsonSerializer<Object> attributesSerializer = provider.findValueSerializer(value.getAttributes().getClass());
+        gen.writeStartObject();
-        // Serialize attributes
+        gen.writeStringField("specversion", value.getAttributes().getSpecVersion().toString());
-        attributesSerializer.serialize(value.getAttributes(), gen, provider);
 
+        // Serialize attributes
+        AttributesInternal attributesInternal = (AttributesInternal) value.getAttributes();
+        try {
+            attributesInternal.visitAttributes(new AttributesSerializer(gen));
+        } catch (RuntimeException e) {
+            throw (IOException) e.getCause();
+        }
+
+        // Serialize extensions
+        try {
+            ((CloudEventImpl) value).visitExtensions(new ExtensionsSerializer(gen, provider));
+        } catch (RuntimeException e) {
+            throw (IOException) e.getCause();
+        }
+
+        // Serialize data
+        Optional<byte[]> dataOptional = value.getData();
+        String contentType = attributesInternal.getDataContentType().orElse(null);
+        if (dataOptional.isPresent()) {
+            if (JsonFormat.shouldSerializeBase64(contentType)) {
+                switch (attributesInternal.getSpecVersion()) {
+                    case V03:
+                        gen.writeStringField("datacontentencoding", "base64");
+                        gen.writeFieldName("data");
+                        gen.writeBinary(dataOptional.get());
+                        break;
+                    case V1:
+                        gen.writeFieldName("data_base64");
+                        gen.writeBinary(dataOptional.get());
+                        break;
+                }
+            } else if (JsonFormat.isJsonContentType(contentType)) {
+                // TODO really bad, is there another solution out there?
+                char[] data = new String(dataOptional.get(), StandardCharsets.UTF_8).toCharArray();
+                gen.writeFieldName("data");
+                gen.writeRawValue(data, 0, data.length);
+            } else {
+                byte[] data = dataOptional.get();
+                gen.writeFieldName("data");
+                gen.writeUTF8String(data, 0, data.length);
+            }
+        }
+        gen.writeEndObject();
     }
 }

formats/json-jackson/src/main/java/io/cloudevents/format/json/JsonFormat.java

@@ -31,9 +31,14 @@ import java.util.Set;
 
 public final class JsonFormat implements EventFormat {
 
+    public static final String CONTENT_TYPE = "application/cloudevents+json";
+
     public static final ObjectMapper MAPPER = new ObjectMapper();
 
     static {
+        // Add CloudEvent serializer/deserializer
+        MAPPER.registerModule(getCloudEventJacksonModule());
+
         // add ZonedDateTime ser/de
         final SimpleModule module = new SimpleModule("Custom ZonedDateTime");
         module.addSerializer(ZonedDateTime.class, new ZonedDateTimeSerializer());
@@ -41,8 +46,8 @@ public final class JsonFormat implements EventFormat {
         MAPPER.registerModule(module);
     }
 
-    private boolean forceDataBase64Serialization = false;
+    private static boolean forceDataBase64Serialization = false;
-    private boolean forceStringSerialization = false;
+    private static boolean forceStringSerialization = false;
 
     @Override
     public byte[] serialize(CloudEvent event) throws EventSerializationException {
@@ -64,16 +69,34 @@ public final class JsonFormat implements EventFormat {
 
     @Override
     public Set<String> supportedContentTypes() {
-        return Collections.singleton("application/cloudevents+json");
+        return Collections.singleton(CONTENT_TYPE);
     }
 
-    public JsonFormat forceDataBase64Serialization(boolean forceBase64Serialization) {
+    public static SimpleModule getCloudEventJacksonModule() {
-        this.forceDataBase64Serialization = forceBase64Serialization;
+        final SimpleModule ceModule = new SimpleModule("CloudEvent");
-        return this;
+        ceModule.addSerializer(CloudEvent.class, new CloudEventSerializer());
+        ceModule.addDeserializer(CloudEvent.class, new CloudEventDeserializer());
+        return ceModule;
     }
 
-    public JsonFormat forceDataStringSerialization(boolean forceStringSerialization) {
+    public static void forceDataBase64Serialization(boolean forceBase64Serialization) {
-        this.forceStringSerialization = forceStringSerialization;
+        JsonFormat.forceDataBase64Serialization = forceBase64Serialization;
-        return this;
+    }
+
+    public static void forceDataStringSerialization(boolean forceStringSerialization) {
+        JsonFormat.forceStringSerialization = forceStringSerialization;
+    }
+
+    protected static boolean isJsonContentType(String contentType) {
+        // If content type, spec states that we should assume is json
+        return contentType == null || contentType.startsWith("application/json") || contentType.startsWith("text/json");
+    }
+
+    protected static boolean shouldSerializeBase64(String contentType) {
+        if (isJsonContentType(contentType)) {
+            return JsonFormat.forceDataBase64Serialization;
+        } else {
+            return !JsonFormat.forceStringSerialization;
+        }
     }
 }

formats/json-jackson/src/test/java/io/cloudevents/format/json/JsonFormatTest.java

@@ -123,7 +123,7 @@ class JsonFormatTest {
     }
 
     private EventFormat getFormat() {
-        return EventFormatProvider.getInstance().resolveFormat("application/cloudevents+json");
+        return EventFormatProvider.getInstance().resolveFormat(JsonFormat.CONTENT_TYPE);
     }
 
 }