io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionUtil Maven / Gradle / Ivy
/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you 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 io.netty.handler.codec.http.websocketx.extensions;
import io.netty.handler.codec.http.HttpHeaderNames;
import io.netty.handler.codec.http.HttpHeaderValues;
import io.netty.handler.codec.http.HttpHeaders;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public final class WebSocketExtensionUtil {
private static final String EXTENSION_SEPARATOR = ",";
private static final String PARAMETER_SEPARATOR = ";";
private static final char PARAMETER_EQUAL = '=';
private static final Pattern PARAMETER = Pattern.compile("^([^=]+)(=[\\\"]?([^\\\"]+)[\\\"]?)?$");
static boolean isWebsocketUpgrade(HttpHeaders headers) {
//this contains check does not allocate an iterator, and most requests are not upgrades
//so we do the contains check first before checking for specific values
return headers.contains(HttpHeaderNames.UPGRADE) &&
headers.containsValue(HttpHeaderNames.CONNECTION, HttpHeaderValues.UPGRADE, true) &&
headers.contains(HttpHeaderNames.UPGRADE, HttpHeaderValues.WEBSOCKET, true);
}
public static List extractExtensions(String extensionHeader) {
String[] rawExtensions = extensionHeader.split(EXTENSION_SEPARATOR);
if (rawExtensions.length > 0) {
List extensions = new ArrayList(rawExtensions.length);
for (String rawExtension : rawExtensions) {
String[] extensionParameters = rawExtension.split(PARAMETER_SEPARATOR);
String name = extensionParameters[0].trim();
Map parameters;
if (extensionParameters.length > 1) {
parameters = new HashMap(extensionParameters.length - 1);
for (int i = 1; i < extensionParameters.length; i++) {
String parameter = extensionParameters[i].trim();
Matcher parameterMatcher = PARAMETER.matcher(parameter);
if (parameterMatcher.matches() && parameterMatcher.group(1) != null) {
parameters.put(parameterMatcher.group(1), parameterMatcher.group(3));
}
}
} else {
parameters = Collections.emptyMap();
}
extensions.add(new WebSocketExtensionData(name, parameters));
}
return extensions;
} else {
return Collections.emptyList();
}
}
static String computeMergeExtensionsHeaderValue(String userDefinedHeaderValue,
List extraExtensions) {
List userDefinedExtensions =
userDefinedHeaderValue != null ?
extractExtensions(userDefinedHeaderValue) :
Collections.emptyList();
for (WebSocketExtensionData userDefined: userDefinedExtensions) {
WebSocketExtensionData matchingExtra = null;
int i;
for (i = 0; i < extraExtensions.size(); i ++) {
WebSocketExtensionData extra = extraExtensions.get(i);
if (extra.name().equals(userDefined.name())) {
matchingExtra = extra;
break;
}
}
if (matchingExtra == null) {
extraExtensions.add(userDefined);
} else {
// merge with higher precedence to user defined parameters
Map mergedParameters = new HashMap(matchingExtra.parameters());
mergedParameters.putAll(userDefined.parameters());
extraExtensions.set(i, new WebSocketExtensionData(matchingExtra.name(), mergedParameters));
}
}
StringBuilder sb = new StringBuilder(150);
for (WebSocketExtensionData data: extraExtensions) {
sb.append(data.name());
for (Entry parameter : data.parameters().entrySet()) {
sb.append(PARAMETER_SEPARATOR);
sb.append(parameter.getKey());
if (parameter.getValue() != null) {
sb.append(PARAMETER_EQUAL);
sb.append(parameter.getValue());
}
}
sb.append(EXTENSION_SEPARATOR);
}
if (!extraExtensions.isEmpty()) {
sb.setLength(sb.length() - EXTENSION_SEPARATOR.length());
}
return sb.toString();
}
private WebSocketExtensionUtil() {
// Unused
}
}