EmbeddedHeaderUtils.java
/*
* Copyright 2014-present 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.cloud.stream.binder;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import tools.jackson.databind.ObjectMapper;
import org.springframework.cloud.function.json.JacksonMapper;
import org.springframework.cloud.function.json.JsonMapper;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.util.ObjectUtils;
/**
* Encodes requested headers into payload with format
* {@code 0xff, n(1), [ [lenHdr(1), hdr, lenValue(4), value] ... ]}. The 0xff indicates
* this new format; n is number of headers (max 255); for each header, the name length (1
* byte) is followed by the name, followed by the value length (int) followed by the value
* (json).
* <p>
* Previously, there was no leading 0xff; the value length was 1 byte and only String
* header values were supported (no JSON conversion).
*
* @author Eric Bottard
* @author Gary Russell
* @author Ilayaperumal Gopinathan
* @author Marius Bogoevici
* @since 1.2
*/
public abstract class EmbeddedHeaderUtils {
//private static final Jackson2JsonObjectMapper objectMapper = new Jackson2JsonObjectMapper();
private static final JsonMapper jsonMapper = new JacksonMapper(new ObjectMapper());
public static String decodeExceptionMessage(Message<?> requestMessage) {
return "Could not convert message: " + requestMessage;
}
/**
* Return a new message where some of the original headers of {@code original} have
* been embedded into the new message payload.
*
* @param original original message
* @param headers headers to embedd
* @return a new message
*/
public static byte[] embedHeaders(MessageValues original, String... headers) {
try {
byte[][] headerValues = new byte[headers.length][];
int n = 0;
int headerCount = 0;
int headersLength = 0;
for (String header : headers) {
Object value = original.get(header);
if (value != null) {
String json = jsonMapper.toString(value);
headerValues[n] = json.getBytes(StandardCharsets.UTF_8);
headerCount++;
headersLength += header.length() + headerValues[n++].length;
} else {
headerValues[n++] = null;
}
}
// 0xff, n(1), [ [lenHdr(1), hdr, lenValue(4), value] ... ]
byte[] newPayload = new byte[((byte[]) original.getPayload()).length
+ headersLength + headerCount * 5 + 2];
ByteBuffer byteBuffer = ByteBuffer.wrap(newPayload);
byteBuffer.put((byte) 0xff); // signal new format
byteBuffer.put((byte) headerCount);
for (int i = 0; i < headers.length; i++) {
if (headerValues[i] != null) {
byteBuffer.put((byte) headers[i].length());
byteBuffer.put(headers[i].getBytes(StandardCharsets.UTF_8));
byteBuffer.putInt(headerValues[i].length);
byteBuffer.put(headerValues[i]);
}
}
byteBuffer.put((byte[]) original.getPayload());
return byteBuffer.array();
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
/**
* Return a message where headers, that were originally embedded into the payload,
* have been promoted back to actual headers. The new payload is now the original
* payload.
*
* @param message the message to extract headers
* @param copyRequestHeaders boolean value to specify if the request headers should be
* copied
* @return wrapped message values
* @throws Exception when extraction failed
*/
public static MessageValues extractHeaders(Message<byte[]> message,
boolean copyRequestHeaders) throws Exception {
return extractHeaders(message.getPayload(), copyRequestHeaders,
message.getHeaders());
}
private static MessageValues extractHeaders(byte[] payload,
boolean copyRequestHeaders, MessageHeaders requestHeaders) throws Exception {
ByteBuffer byteBuffer = ByteBuffer.wrap(payload);
int headerCount = byteBuffer.get() & 0xff;
if (headerCount == 0xff) {
headerCount = byteBuffer.get() & 0xff;
Map<String, Object> headers = new HashMap<String, Object>();
for (int i = 0; i < headerCount; i++) {
int len = byteBuffer.get() & 0xff;
String headerName = new String(payload, byteBuffer.position(), len,
StandardCharsets.UTF_8);
byteBuffer.position(byteBuffer.position() + len);
len = byteBuffer.getInt();
String headerValue = new String(payload, byteBuffer.position(), len,
StandardCharsets.UTF_8);
Object headerContent = jsonMapper.fromJson(headerValue, Object.class);
headers.put(headerName, headerContent);
byteBuffer.position(byteBuffer.position() + len);
}
byte[] newPayload = new byte[byteBuffer.remaining()];
byteBuffer.get(newPayload);
return buildMessageValues(newPayload, headers, copyRequestHeaders,
requestHeaders);
} else {
return buildMessageValues(payload, new HashMap<>(), copyRequestHeaders,
requestHeaders);
}
}
/**
* Return a message where headers, that were originally embedded into the payload,
* have been promoted back to actual headers. The new payload is now the original
* payload.
*
* @param payload the message payload
* @return the message with extracted headers
* @throws Exception when extraction failed
*/
public static MessageValues extractHeaders(byte[] payload) throws Exception {
return extractHeaders(payload, false, null);
}
private static MessageValues buildMessageValues(byte[] payload,
Map<String, Object> headers, boolean copyRequestHeaders,
MessageHeaders requestHeaders) {
MessageValues messageValues = new MessageValues(payload, headers);
if (copyRequestHeaders && requestHeaders != null) {
messageValues.copyHeadersIfAbsent(requestHeaders);
}
return messageValues;
}
public static String[] headersToEmbed(String[] configuredHeaders) {
String[] headersToMap;
if (ObjectUtils.isEmpty(configuredHeaders)) {
headersToMap = BinderHeaders.STANDARD_HEADERS;
} else {
String[] combinedHeadersToMap = Arrays.copyOfRange(
BinderHeaders.STANDARD_HEADERS, 0,
BinderHeaders.STANDARD_HEADERS.length + configuredHeaders.length);
System.arraycopy(configuredHeaders, 0, combinedHeadersToMap,
BinderHeaders.STANDARD_HEADERS.length, configuredHeaders.length);
headersToMap = combinedHeadersToMap;
}
return headersToMap;
}
/**
* Return true if the bytes might have embedded headers. (First byte is 0xff and long
* enough for at least one header).
*
* @param bytes the array.
* @return true if it may have embedded headers.
*/
public static boolean mayHaveEmbeddedHeaders(byte[] bytes) {
return bytes.length > 8 && (bytes[0] & 0xff) == 0xff;
}
}