GH-1066: Protect against null Headers

Resolves #1066

Certain clients (e.g. mapR) that emulate the Kafka clients do not properly
populate the `ConsumerRecord.headers()` field.

Check for null before mapping; also check `timestampType`.

**cherry-pick to 2.2.x, 2.1.x**

Author: garyrussell

spring-kafka/src/main/java/org/springframework/kafka/support/converter/BatchMessagingMessageConverter.java

@@ -125,6 +125,7 @@ public RecordMessageConverter getRecordMessageConverter() {
 	@Override
 	public Message<?> toMessage(List<ConsumerRecord<?, ?>> records, Acknowledgment acknowledgment,
 			Consumer<?, ?> consumer, Type type) {
+
 		KafkaMessageHeaders kafkaMessageHeaders = new KafkaMessageHeaders(this.generateMessageId,
 				this.generateTimestamp);
 
@@ -156,9 +157,11 @@ public Message<?> toMessage(List<ConsumerRecord<?, ?>> records, Acknowledgment a
 			topics.add(record.topic());
 			partitions.add(record.partition());
 			offsets.add(record.offset());
-			timestampTypes.add(record.timestampType().name());
+			if (record.timestampType() != null) {
+				timestampTypes.add(record.timestampType().name());
+			}
 			timestamps.add(record.timestamp());
-			if (this.headerMapper != null) {
+			if (this.headerMapper != null && record.headers() != null) {
 				Map<String, Object> converted = new HashMap<>();
 				this.headerMapper.toHeaders(record.headers(), converted);
 				convertedHeaders.add(converted);

spring-kafka/src/main/java/org/springframework/kafka/support/converter/MessageConverter.java

@@ -42,7 +42,8 @@ static String getGroupid() {
 	}
 
 	default void commonHeaders(Acknowledgment acknowledgment, Consumer<?, ?> consumer, Map<String, Object> rawHeaders,
-			Object theKey, Object topic, Object partition, Object offset, Object timestampType, Object timestamp) {
+			Object theKey, Object topic, Object partition, Object offset,
+			@Nullable Object timestampType, Object timestamp) {
 
 		rawHeaders.put(KafkaHeaders.RECEIVED_MESSAGE_KEY, theKey);
 		rawHeaders.put(KafkaHeaders.RECEIVED_TOPIC, topic);

spring-kafka/src/main/java/org/springframework/kafka/support/converter/MessagingMessageConverter.java

@@ -101,11 +101,12 @@ public void setHeaderMapper(KafkaHeaderMapper headerMapper) {
 	@Override
 	public Message<?> toMessage(ConsumerRecord<?, ?> record, Acknowledgment acknowledgment, Consumer<?, ?> consumer,
 			Type type) {
+
 		KafkaMessageHeaders kafkaMessageHeaders = new KafkaMessageHeaders(this.generateMessageId,
 				this.generateTimestamp);
 
 		Map<String, Object> rawHeaders = kafkaMessageHeaders.getRawHeaders();
-		if (this.headerMapper != null) {
+		if (this.headerMapper != null && record.headers() != null) {
 			this.headerMapper.toHeaders(record.headers(), rawHeaders);
 		}
 		else {
@@ -117,8 +118,9 @@ public Message<?> toMessage(ConsumerRecord<?, ?> record, Acknowledgment acknowle
 			}
 			rawHeaders.put(KafkaHeaders.NATIVE_HEADERS, record.headers());
 		}
+		String ttName = record.timestampType() != null ? record.timestampType().name() : null;
 		commonHeaders(acknowledgment, consumer, rawHeaders, record.key(), record.topic(), record.partition(),
-				record.offset(), record.timestampType().name(), record.timestamp());
+				record.offset(), ttName, record.timestamp());
 
 		return MessageBuilder.createMessage(extractAndConvertValue(record, type), kafkaMessageHeaders);
 	}

spring-kafka/src/test/java/org/springframework/kafka/support/converter/BatchMessageConverterTests.java

@@ -21,6 +21,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -115,4 +116,18 @@ private MessageHeaders testGuts(BatchMessageConverter batchMessageConverter) {
 		return headers;
 	}
 
+	@SuppressWarnings("unchecked")
+	@Test
+	public void missingHeaders() {
+		BatchMessageConverter converter = new BatchMessagingMessageConverter();
+		Headers nullHeaders = null;
+		ConsumerRecord<String, String> record = new ConsumerRecord<>("foo", 1, 42, -1L, null, 0L, 0, 0, "bar", "baz",
+				nullHeaders);
+		List<ConsumerRecord<?, ?>> records = Collections.singletonList(record);
+		Message<?> message = converter.toMessage(records, null, null, null);
+		assertThat(((List<String>) message.getPayload())).contains("baz");
+		assertThat(message.getHeaders().get(KafkaHeaders.RECEIVED_TOPIC, List.class)).contains("foo");
+		assertThat(message.getHeaders().get(KafkaHeaders.RECEIVED_MESSAGE_KEY, List.class)).contains("bar");
+	}
+
 }

spring-kafka/src/test/java/org/springframework/kafka/support/converter/MessagingMessageConverterTests.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.kafka.support.converter;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.common.header.Headers;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.kafka.support.KafkaHeaders;
+import org.springframework.messaging.Message;
+
+/**
+ * @author Gary Russell
+ * @since 2.1.13
+ *
+ */
+public class MessagingMessageConverterTests {
+
+	@Test
+	void missingHeaders() {
+		MessagingMessageConverter converter = new MessagingMessageConverter();
+		Headers nullHeaders = null;
+		ConsumerRecord<String, String> record = new ConsumerRecord<>("foo", 1, 42, -1L, null, 0L, 0, 0, "bar", "baz",
+				nullHeaders);
+		Message<?> message = converter.toMessage(record, null, null, null);
+		assertThat(message.getPayload()).isEqualTo("baz");
+		assertThat(message.getHeaders().get(KafkaHeaders.RECEIVED_TOPIC)).isEqualTo("foo");
+		assertThat(message.getHeaders().get(KafkaHeaders.RECEIVED_MESSAGE_KEY)).isEqualTo("bar");
+	}
+
+}