199 lines
8.1 KiB
Java
199 lines
8.1 KiB
Java
/*
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* Copyright 2014 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.http.websocketx.extensions.compression;
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import static io.netty.handler.codec.http.websocketx.extensions.compression.
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PerMessageDeflateServerExtensionHandshaker.*;
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import io.netty.handler.codec.compression.ZlibCodecFactory;
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import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtension;
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import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtensionHandshaker;
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import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
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import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder;
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import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
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import java.util.HashMap;
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import java.util.Iterator;
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import java.util.Map.Entry;
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/**
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* <a href="http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-18">permessage-deflate</a>
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* handshake implementation.
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*/
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public final class PerMessageDeflateClientExtensionHandshaker implements WebSocketClientExtensionHandshaker {
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private final int compressionLevel;
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private final boolean allowClientWindowSize;
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private final int requestedServerWindowSize;
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private final boolean allowClientNoContext;
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private final boolean requestedServerNoContext;
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/**
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* Constructor with default configuration.
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*/
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public PerMessageDeflateClientExtensionHandshaker() {
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this(6, ZlibCodecFactory.isSupportingWindowSizeAndMemLevel(), MAX_WINDOW_SIZE, false, false);
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}
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/**
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* Constructor with custom configuration.
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*
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* @param compressionLevel
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* Compression level between 0 and 9 (default is 6).
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* @param allowClientWindowSize
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* allows WebSocket server to customize the client inflater window size
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* (default is false).
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* @param requestedServerWindowSize
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* indicates the requested sever window size to use if server inflater is customizable.
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* @param allowClientNoContext
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* allows WebSocket server to activate client_no_context_takeover
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* (default is false).
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* @param requestedServerNoContext
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* indicates if client needs to activate server_no_context_takeover
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* if server is compatible with (default is false).
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*/
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public PerMessageDeflateClientExtensionHandshaker(int compressionLevel,
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boolean allowClientWindowSize, int requestedServerWindowSize,
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boolean allowClientNoContext, boolean requestedServerNoContext) {
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if (requestedServerWindowSize > MAX_WINDOW_SIZE || requestedServerWindowSize < MIN_WINDOW_SIZE) {
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throw new IllegalArgumentException(
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"requestedServerWindowSize: " + requestedServerWindowSize + " (expected: 8-15)");
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}
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if (compressionLevel < 0 || compressionLevel > 9) {
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throw new IllegalArgumentException(
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"compressionLevel: " + compressionLevel + " (expected: 0-9)");
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}
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this.compressionLevel = compressionLevel;
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this.allowClientWindowSize = allowClientWindowSize;
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this.requestedServerWindowSize = requestedServerWindowSize;
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this.allowClientNoContext = allowClientNoContext;
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this.requestedServerNoContext = requestedServerNoContext;
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}
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@Override
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public WebSocketExtensionData newRequestData() {
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HashMap<String, String> parameters = new HashMap<String, String>(4);
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if (requestedServerWindowSize != MAX_WINDOW_SIZE) {
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parameters.put(SERVER_NO_CONTEXT, null);
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}
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if (allowClientNoContext) {
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parameters.put(CLIENT_NO_CONTEXT, null);
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}
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if (requestedServerWindowSize != MAX_WINDOW_SIZE) {
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parameters.put(SERVER_MAX_WINDOW, Integer.toString(requestedServerWindowSize));
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}
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if (allowClientWindowSize) {
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parameters.put(CLIENT_MAX_WINDOW, null);
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}
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return new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters);
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}
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@Override
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public WebSocketClientExtension handshakeExtension(WebSocketExtensionData extensionData) {
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if (!PERMESSAGE_DEFLATE_EXTENSION.equals(extensionData.name())) {
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return null;
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}
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boolean succeed = true;
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int clientWindowSize = MAX_WINDOW_SIZE;
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int serverWindowSize = MAX_WINDOW_SIZE;
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boolean serverNoContext = false;
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boolean clientNoContext = false;
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Iterator<Entry<String, String>> parametersIterator =
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extensionData.parameters().entrySet().iterator();
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while (succeed && parametersIterator.hasNext()) {
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Entry<String, String> parameter = parametersIterator.next();
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if (CLIENT_MAX_WINDOW.equalsIgnoreCase(parameter.getKey())) {
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// allowed client_window_size_bits
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if (allowClientWindowSize) {
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clientWindowSize = Integer.parseInt(parameter.getValue());
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} else {
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succeed = false;
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}
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} else if (SERVER_MAX_WINDOW.equalsIgnoreCase(parameter.getKey())) {
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// acknowledged server_window_size_bits
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serverWindowSize = Integer.parseInt(parameter.getValue());
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if (clientWindowSize > MAX_WINDOW_SIZE || clientWindowSize < MIN_WINDOW_SIZE) {
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succeed = false;
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}
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} else if (CLIENT_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
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// allowed client_no_context_takeover
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if (allowClientNoContext) {
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clientNoContext = true;
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} else {
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succeed = false;
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}
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} else if (SERVER_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
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// acknowledged server_no_context_takeover
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if (requestedServerNoContext) {
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serverNoContext = true;
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} else {
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succeed = false;
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}
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} else {
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// unknown parameter
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succeed = false;
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}
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}
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if ((requestedServerNoContext && !serverNoContext) ||
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requestedServerWindowSize != serverWindowSize) {
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succeed = false;
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}
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if (succeed) {
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return new PermessageDeflateExtension(serverNoContext, serverWindowSize,
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clientNoContext, clientWindowSize);
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} else {
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return null;
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}
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}
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private final class PermessageDeflateExtension implements WebSocketClientExtension {
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private final boolean serverNoContext;
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private final int serverWindowSize;
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private final boolean clientNoContext;
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private final int clientWindowSize;
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@Override
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public int rsv() {
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return RSV1;
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}
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PermessageDeflateExtension(boolean serverNoContext, int serverWindowSize,
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boolean clientNoContext, int clientWindowSize) {
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this.serverNoContext = serverNoContext;
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this.serverWindowSize = serverWindowSize;
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this.clientNoContext = clientNoContext;
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this.clientWindowSize = clientWindowSize;
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}
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@Override
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public WebSocketExtensionEncoder newExtensionEncoder() {
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return new PerMessageDeflateEncoder(compressionLevel, clientWindowSize, clientNoContext);
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}
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@Override
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public WebSocketExtensionDecoder newExtensionDecoder() {
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return new PerMessageDeflateDecoder(serverNoContext);
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}
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}
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}
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