fc6e668186
Motivation: Add user possibility to skip the evaluation of certain web socket extension, for example we can skip compression extension for messages that already compressed or very small and etc. Modification: This pull request is related with #5669 Result: User can set to WebSocketClientExtensionHandshaker or WebSocketServerExtensionHandshaker a filter to skip the evaluation of certain extension.
234 lines
10 KiB
Java
234 lines
10 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 io.netty.handler.codec.compression.ZlibCodecFactory;
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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 io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionFilterProvider;
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import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtension;
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import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtensionHandshaker;
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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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import static io.netty.util.internal.ObjectUtil.*;
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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 PerMessageDeflateServerExtensionHandshaker implements WebSocketServerExtensionHandshaker {
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public static final int MIN_WINDOW_SIZE = 8;
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public static final int MAX_WINDOW_SIZE = 15;
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static final String PERMESSAGE_DEFLATE_EXTENSION = "permessage-deflate";
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static final String CLIENT_MAX_WINDOW = "client_max_window_bits";
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static final String SERVER_MAX_WINDOW = "server_max_window_bits";
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static final String CLIENT_NO_CONTEXT = "client_no_context_takeover";
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static final String SERVER_NO_CONTEXT = "server_no_context_takeover";
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private final int compressionLevel;
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private final boolean allowServerWindowSize;
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private final int preferredClientWindowSize;
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private final boolean allowServerNoContext;
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private final boolean preferredClientNoContext;
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private final WebSocketExtensionFilterProvider extensionFilterProvider;
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/**
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* Constructor with default configuration.
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*/
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public PerMessageDeflateServerExtensionHandshaker() {
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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 allowServerWindowSize
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* allows WebSocket client to customize the server inflater window size
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* (default is false).
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* @param preferredClientWindowSize
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* indicates the preferred client window size to use if client inflater is customizable.
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* @param allowServerNoContext
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* allows WebSocket client to activate server_no_context_takeover
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* (default is false).
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* @param preferredClientNoContext
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* indicates if server prefers to activate client_no_context_takeover
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* if client is compatible with (default is false).
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*/
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public PerMessageDeflateServerExtensionHandshaker(int compressionLevel, boolean allowServerWindowSize,
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int preferredClientWindowSize,
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boolean allowServerNoContext, boolean preferredClientNoContext) {
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this(compressionLevel, allowServerWindowSize, preferredClientWindowSize, allowServerNoContext,
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preferredClientNoContext, WebSocketExtensionFilterProvider.DEFAULT);
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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 allowServerWindowSize
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* allows WebSocket client to customize the server inflater window size
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* (default is false).
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* @param preferredClientWindowSize
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* indicates the preferred client window size to use if client inflater is customizable.
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* @param allowServerNoContext
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* allows WebSocket client to activate server_no_context_takeover
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* (default is false).
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* @param preferredClientNoContext
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* indicates if server prefers to activate client_no_context_takeover
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* if client is compatible with (default is false).
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* @param extensionFilterProvider
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* provides server extension filters for per message deflate encoder and decoder.
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*/
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public PerMessageDeflateServerExtensionHandshaker(int compressionLevel, boolean allowServerWindowSize,
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int preferredClientWindowSize,
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boolean allowServerNoContext, boolean preferredClientNoContext,
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WebSocketExtensionFilterProvider extensionFilterProvider) {
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if (preferredClientWindowSize > MAX_WINDOW_SIZE || preferredClientWindowSize < MIN_WINDOW_SIZE) {
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throw new IllegalArgumentException(
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"preferredServerWindowSize: " + preferredClientWindowSize + " (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.allowServerWindowSize = allowServerWindowSize;
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this.preferredClientWindowSize = preferredClientWindowSize;
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this.allowServerNoContext = allowServerNoContext;
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this.preferredClientNoContext = preferredClientNoContext;
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this.extensionFilterProvider = checkNotNull(extensionFilterProvider, "extensionFilterProvider");
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}
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@Override
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public WebSocketServerExtension 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 deflateEnabled = 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 (deflateEnabled && 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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// use preferred clientWindowSize because client is compatible with customization
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clientWindowSize = preferredClientWindowSize;
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} else if (SERVER_MAX_WINDOW.equalsIgnoreCase(parameter.getKey())) {
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// use provided windowSize if it is allowed
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if (allowServerWindowSize) {
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serverWindowSize = Integer.parseInt(parameter.getValue());
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if (serverWindowSize > MAX_WINDOW_SIZE || serverWindowSize < MIN_WINDOW_SIZE) {
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deflateEnabled = false;
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}
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} else {
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deflateEnabled = false;
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}
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} else if (CLIENT_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
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// use preferred clientNoContext because client is compatible with customization
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clientNoContext = preferredClientNoContext;
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} else if (SERVER_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
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// use server no context if allowed
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if (allowServerNoContext) {
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serverNoContext = true;
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} else {
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deflateEnabled = false;
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}
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} else {
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// unknown parameter
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deflateEnabled = false;
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}
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}
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if (deflateEnabled) {
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return new PermessageDeflateExtension(compressionLevel, serverNoContext,
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serverWindowSize, clientNoContext, clientWindowSize, extensionFilterProvider);
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} else {
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return null;
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}
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}
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private static class PermessageDeflateExtension implements WebSocketServerExtension {
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private final int compressionLevel;
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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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private final WebSocketExtensionFilterProvider extensionFilterProvider;
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PermessageDeflateExtension(int compressionLevel, boolean serverNoContext,
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int serverWindowSize, boolean clientNoContext, int clientWindowSize,
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WebSocketExtensionFilterProvider extensionFilterProvider) {
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this.compressionLevel = compressionLevel;
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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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this.extensionFilterProvider = extensionFilterProvider;
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}
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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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@Override
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public WebSocketExtensionEncoder newExtensionEncoder() {
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return new PerMessageDeflateEncoder(compressionLevel, serverWindowSize, serverNoContext,
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extensionFilterProvider.encoderFilter());
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}
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@Override
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public WebSocketExtensionDecoder newExtensionDecoder() {
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return new PerMessageDeflateDecoder(clientNoContext, extensionFilterProvider.decoderFilter());
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}
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@Override
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public WebSocketExtensionData newReponseData() {
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HashMap<String, String> parameters = new HashMap<String, String>(4);
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if (serverNoContext) {
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parameters.put(SERVER_NO_CONTEXT, null);
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}
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if (clientNoContext) {
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parameters.put(CLIENT_NO_CONTEXT, null);
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}
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if (serverWindowSize != MAX_WINDOW_SIZE) {
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parameters.put(SERVER_MAX_WINDOW, Integer.toString(serverWindowSize));
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}
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if (clientWindowSize != MAX_WINDOW_SIZE) {
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parameters.put(CLIENT_MAX_WINDOW, Integer.toString(clientWindowSize));
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}
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return new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters);
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}
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}
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}
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