/*
* Copyright 2002-2016 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
*
* http://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.messaging.simp.stomp;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.messaging.Message;
import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
import org.springframework.messaging.simp.SimpMessageType;
import org.springframework.messaging.support.NativeMessageHeaderAccessor;
import org.springframework.util.Assert;
/**
* An encoder for STOMP frames.
*
* @author Andy Wilkinson
* @author Rossen Stoyanchev
* @since 4.0
* @see StompDecoder
*/
public class StompEncoder {
private static final byte LF = '\n';
private static final byte COLON = ':';
private static final Log logger = LogFactory.getLog(StompEncoder.class);
private static final int HEADER_KEY_CACHE_LIMIT = 32;
private final Map<String, byte[]> headerKeyAccessCache =
new ConcurrentHashMap<>(HEADER_KEY_CACHE_LIMIT);
@SuppressWarnings("serial")
private final Map<String, byte[]> headerKeyUpdateCache =
new LinkedHashMap<String, byte[]>(HEADER_KEY_CACHE_LIMIT, 0.75f, true) {
@Override
protected boolean removeEldestEntry(Map.Entry<String, byte[]> eldest) {
if (size() > HEADER_KEY_CACHE_LIMIT) {
headerKeyAccessCache.remove(eldest.getKey());
return true;
}
else {
return false;
}
}
};
/**
* Encodes the given STOMP {@code message} into a {@code byte[]}
* @param message the message to encode
* @return the encoded message
*/
public byte[] encode(Message<byte[]> message) {
return encode(message.getHeaders(), message.getPayload());
}
/**
* Encodes the given payload and headers into a {@code byte[]}.
* @param headers the headers
* @param payload the payload
* @return the encoded message
*/
public byte[] encode(Map<String, Object> headers, byte[] payload) {
Assert.notNull(headers, "'headers' is required");
Assert.notNull(payload, "'payload' is required");
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream(128 + payload.length);
DataOutputStream output = new DataOutputStream(baos);
if (SimpMessageType.HEARTBEAT.equals(SimpMessageHeaderAccessor.getMessageType(headers))) {
if (logger.isTraceEnabled()) {
logger.trace("Encoding heartbeat");
}
output.write(StompDecoder.HEARTBEAT_PAYLOAD);
}
else {
StompCommand command = StompHeaderAccessor.getCommand(headers);
if (command == null) {
throw new IllegalStateException("Missing STOMP command: " + headers);
}
output.write(command.toString().getBytes(StandardCharsets.UTF_8));
output.write(LF);
writeHeaders(command, headers, payload, output);
output.write(LF);
writeBody(payload, output);
output.write((byte) 0);
}
return baos.toByteArray();
}
catch (IOException ex) {
throw new StompConversionException("Failed to encode STOMP frame, headers=" + headers, ex);
}
}
private void writeHeaders(StompCommand command, Map<String, Object> headers, byte[] payload,
DataOutputStream output) throws IOException {
@SuppressWarnings("unchecked")
Map<String,List<String>> nativeHeaders =
(Map<String, List<String>>) headers.get(NativeMessageHeaderAccessor.NATIVE_HEADERS);
if (logger.isTraceEnabled()) {
logger.trace("Encoding STOMP " + command + ", headers=" + nativeHeaders);
}
if (nativeHeaders == null) {
return;
}
boolean shouldEscape = (command != StompCommand.CONNECT && command != StompCommand.CONNECTED);
for (Entry<String, List<String>> entry : nativeHeaders.entrySet()) {
if (command.requiresContentLength() && "content-length".equals(entry.getKey())) {
continue;
}
List<String> values = entry.getValue();
if (StompCommand.CONNECT.equals(command) &&
StompHeaderAccessor.STOMP_PASSCODE_HEADER.equals(entry.getKey())) {
values = Collections.singletonList(StompHeaderAccessor.getPasscode(headers));
}
byte[] encodedKey = encodeHeaderKey(entry.getKey(), shouldEscape);
for (String value : values) {
output.write(encodedKey);
output.write(COLON);
output.write(encodeHeaderValue(value, shouldEscape));
output.write(LF);
}
}
if (command.requiresContentLength()) {
int contentLength = payload.length;
output.write("content-length:".getBytes(StandardCharsets.UTF_8));
output.write(Integer.toString(contentLength).getBytes(StandardCharsets.UTF_8));
output.write(LF);
}
}
private byte[] encodeHeaderKey(String input, boolean escape) {
String inputToUse = (escape ? escape(input) : input);
if (this.headerKeyAccessCache.containsKey(inputToUse)) {
return this.headerKeyAccessCache.get(inputToUse);
}
synchronized (this.headerKeyUpdateCache) {
byte[] bytes = this.headerKeyUpdateCache.get(inputToUse);
if (bytes == null) {
bytes = inputToUse.getBytes(StandardCharsets.UTF_8);
this.headerKeyAccessCache.put(inputToUse, bytes);
this.headerKeyUpdateCache.put(inputToUse, bytes);
}
return bytes;
}
}
private byte[] encodeHeaderValue(String input, boolean escape) {
String inputToUse = (escape ? escape(input) : input);
return inputToUse.getBytes(StandardCharsets.UTF_8);
}
/**
* See STOMP Spec 1.2:
* <a href="http://stomp.github.io/stomp-specification-1.2.html#Value_Encoding">"Value Encoding"</a>.
*/
private String escape(String inString) {
StringBuilder sb = null;
for (int i = 0; i < inString.length(); i++) {
char c = inString.charAt(i);
if (c == '\\') {
sb = getStringBuilder(sb, inString, i);
sb.append("\\\\");
}
else if (c == ':') {
sb = getStringBuilder(sb, inString, i);
sb.append("\\c");
}
else if (c == '\n') {
sb = getStringBuilder(sb, inString, i);
sb.append("\\n");
}
else if (c == '\r') {
sb = getStringBuilder(sb, inString, i);
sb.append("\\r");
}
else if (sb != null){
sb.append(c);
}
}
return (sb != null ? sb.toString() : inString);
}
private StringBuilder getStringBuilder(StringBuilder sb, String inString, int i) {
if (sb == null) {
sb = new StringBuilder(inString.length());
sb.append(inString.substring(0, i));
}
return sb;
}
private void writeBody(byte[] payload, DataOutputStream output) throws IOException {
output.write(payload);
}
}