Lazily instantiate HttpServerUpgradeHandler.UpgradeCodec
Related: #3814 Motivation: To implement the support for an upgrade from cleartext HTTP/1.1 connection to cleartext HTTP/2 (h2c) connection, a user usually uses HttpServerUpgradeHandler. It does its job, but it requires a user to instantiate the UpgradeCodecs for all supported protocols upfront. It means redundancy for the connections that are not upgraded. Modifications: - Change the constructor of HttpServerUpgradeHandler - Accept UpgraceCodecFactory instead of UpgradeCodecs - The default constructor of HttpServerUpgradeHandler sets the maxContentLength to 0 now, which shouldn't be a problem because a usual upgrade request is a GET. - Update the examples accordingly Result: A user can instantiate Http2ServerUpgradeCodec and its related objects (Http2Connection, Http2FrameReader/Writer, Http2FrameListener, etc) only when necessary.
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Trustin Lee
parent
950da2eae1
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0ca65f1373
@ -17,21 +17,16 @@ package io.netty.handler.codec.http;
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import io.netty.channel.ChannelFuture;
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import io.netty.channel.ChannelFutureListener;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.util.AsciiString;
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import io.netty.util.ReferenceCountUtil;
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import io.netty.util.ReferenceCounted;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.LinkedHashMap;
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import java.util.LinkedHashSet;
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import java.util.List;
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import java.util.Locale;
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import java.util.Map;
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import java.util.Set;
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import java.util.TreeSet;
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import static io.netty.handler.codec.http.HttpResponseStatus.SWITCHING_PROTOCOLS;
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import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
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import static io.netty.util.internal.ObjectUtil.checkNotNull;
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/**
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* A server-side handler that receives HTTP requests and optionally performs a protocol switch if
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@ -54,12 +49,6 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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* A codec that the source can be upgraded to.
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*/
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public interface UpgradeCodec {
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/**
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* Returns the name of the protocol supported by this codec, as indicated by the
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* {@link HttpHeaderNames#UPGRADE} header.
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*/
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String protocol();
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/**
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* Gets all protocol-specific headers required by this protocol for a successful upgrade.
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* Any supplied header will be required to appear in the {@link HttpHeaderNames#CONNECTION} header as well.
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@ -87,6 +76,20 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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void upgradeTo(ChannelHandlerContext ctx, FullHttpRequest upgradeRequest, FullHttpResponse upgradeResponse);
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}
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/**
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* Creates a new {@link UpgradeCodec} for the requested protocol name.
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*/
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public interface UpgradeCodecFactory {
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/**
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* Invoked by {@link HttpServerUpgradeHandler} for all the requested protocol names in the order of
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* the client preference. The first non-{@code null} {@link UpgradeCodec} returned by this method
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* will be selected.
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*
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* @return a new {@link UpgradeCodec}, or {@code null} if the specified protocol name is not supported
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*/
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UpgradeCodec newUpgradeCodec(String protocol);
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}
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/**
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* User event that is fired to notify about the completion of an HTTP upgrade
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* to another protocol. Contains the original upgrade request so that the response
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@ -160,33 +163,44 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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}
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}
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private final Map<String, UpgradeCodec> upgradeCodecMap;
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private static final String UPGRADE_STRING = HttpHeaderNames.UPGRADE.toString();
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private final SourceCodec sourceCodec;
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private final UpgradeCodecFactory upgradeCodecFactory;
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private boolean handlingUpgrade;
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/**
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* Constructs the upgrader with the supported codecs.
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* <p>
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* The handler instantiated by this constructor will reject an upgrade request with non-empty content.
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* It should not be a concern because an upgrade request is most likely a GET request.
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* If you have a client that sends a non-GET upgrade request, please consider using
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* {@link #HttpServerUpgradeHandler(SourceCodec, UpgradeCodecFactory, int)} to specify the maximum
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* length of the content of an upgrade request.
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* </p>
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*
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* @param sourceCodec the codec that is being used initially.
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* @param upgradeCodecs the codecs (in order of preference) that this server supports
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* upgrading to from the source codec.
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* @param maxContentLength the maximum length of the aggregated content.
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* @param sourceCodec the codec that is being used initially
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* @param upgradeCodecFactory the factory that creates a new upgrade codec
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* for one of the requested upgrade protocols
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*/
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public HttpServerUpgradeHandler(SourceCodec sourceCodec,
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Collection<UpgradeCodec> upgradeCodecs, int maxContentLength) {
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public HttpServerUpgradeHandler(SourceCodec sourceCodec, UpgradeCodecFactory upgradeCodecFactory) {
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this(sourceCodec, upgradeCodecFactory, 0);
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}
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/**
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* Constructs the upgrader with the supported codecs.
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*
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* @param sourceCodec the codec that is being used initially
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* @param upgradeCodecFactory the factory that creates a new upgrade codec
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* for one of the requested upgrade protocols
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* @param maxContentLength the maximum length of the content of an upgrade request
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*/
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public HttpServerUpgradeHandler(
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SourceCodec sourceCodec, UpgradeCodecFactory upgradeCodecFactory, int maxContentLength) {
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super(maxContentLength);
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if (sourceCodec == null) {
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throw new NullPointerException("sourceCodec");
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}
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if (upgradeCodecs == null) {
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throw new NullPointerException("upgradeCodecs");
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}
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this.sourceCodec = sourceCodec;
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upgradeCodecMap = new LinkedHashMap<String, UpgradeCodec>(upgradeCodecs.size());
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for (UpgradeCodec upgradeCodec : upgradeCodecs) {
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String name = upgradeCodec.protocol().toUpperCase(Locale.US);
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upgradeCodecMap.put(name, upgradeCodec);
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}
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this.sourceCodec = checkNotNull(sourceCodec, "sourceCodec");
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this.upgradeCodecFactory = checkNotNull(upgradeCodecFactory, "upgradeCodecFactory");
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}
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@Override
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@ -248,8 +262,20 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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*/
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private boolean upgrade(final ChannelHandlerContext ctx, final FullHttpRequest request) {
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// Select the best protocol based on those requested in the UPGRADE header.
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CharSequence upgradeHeader = request.headers().get(HttpHeaderNames.UPGRADE);
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final UpgradeCodec upgradeCodec = selectUpgradeCodec(upgradeHeader);
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final ArrayList<String> requestedProtocols = splitHeader(request.headers().get(HttpHeaderNames.UPGRADE));
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final int numRequestedProtocols = requestedProtocols.size();
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UpgradeCodec upgradeCodec = null;
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String upgradeProtocol = null;
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for (int i = 0; i < numRequestedProtocols; i ++) {
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final String p = requestedProtocols.get(i);
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final UpgradeCodec c = upgradeCodecFactory.newUpgradeCodec(p);
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if (c != null) {
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upgradeProtocol = p;
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upgradeCodec = c;
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break;
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}
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}
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if (upgradeCodec == null) {
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// None of the requested protocols are supported, don't upgrade.
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return false;
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@ -263,8 +289,8 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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// Make sure the CONNECTION header contains UPGRADE as well as all protocol-specific headers.
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Collection<String> requiredHeaders = upgradeCodec.requiredUpgradeHeaders();
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Set<CharSequence> values = splitHeader(connectionHeader);
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if (!values.contains(HttpHeaderNames.UPGRADE) || !values.containsAll(requiredHeaders)) {
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List<String> values = splitHeader(connectionHeader);
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if (!values.contains(UPGRADE_STRING) || !values.containsAll(requiredHeaders)) {
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return false;
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}
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@ -276,12 +302,14 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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}
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// Create the user event to be fired once the upgrade completes.
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final UpgradeEvent event = new UpgradeEvent(upgradeCodec.protocol(), request);
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final UpgradeEvent event = new UpgradeEvent(upgradeProtocol, request);
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// Prepare and send the upgrade response. Wait for this write to complete before upgrading,
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// since we need the old codec in-place to properly encode the response.
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final FullHttpResponse upgradeResponse = createUpgradeResponse(upgradeCodec);
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final FullHttpResponse upgradeResponse = createUpgradeResponse(upgradeProtocol);
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upgradeCodec.prepareUpgradeResponse(ctx, request, upgradeResponse);
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final UpgradeCodec finalUpgradeCodec = upgradeCodec;
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ctx.writeAndFlush(upgradeResponse).addListener(new ChannelFutureListener() {
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@Override
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public void operationComplete(ChannelFuture future) throws Exception {
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@ -289,7 +317,7 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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if (future.isSuccess()) {
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// Perform the upgrade to the new protocol.
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sourceCodec.upgradeFrom(ctx);
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upgradeCodec.upgradeTo(ctx, request, upgradeResponse);
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finalUpgradeCodec.upgradeTo(ctx, request, upgradeResponse);
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// Notify that the upgrade has occurred. Retain the event to offset
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// the release() in the finally block.
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@ -309,33 +337,13 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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return true;
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}
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/**
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* Looks up the most desirable supported upgrade codec from the list of choices in the UPGRADE
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* header. If no suitable codec was found, returns {@code null}.
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*/
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private UpgradeCodec selectUpgradeCodec(CharSequence upgradeHeader) {
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Set<CharSequence> requestedProtocols = splitHeader(upgradeHeader);
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// Retain only the protocols that are in the protocol map. Maintain the original insertion
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// order into the protocolMap, so that the first one in the remaining set is the most
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// desirable protocol for the server.
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Set<String> supportedProtocols = new LinkedHashSet<String>(upgradeCodecMap.keySet());
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supportedProtocols.retainAll(requestedProtocols);
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if (!supportedProtocols.isEmpty()) {
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String protocol = supportedProtocols.iterator().next().toUpperCase(Locale.US);
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return upgradeCodecMap.get(protocol);
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}
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return null;
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}
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/**
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* Creates the 101 Switching Protocols response message.
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*/
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private static FullHttpResponse createUpgradeResponse(UpgradeCodec upgradeCodec) {
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private static FullHttpResponse createUpgradeResponse(String upgradeProtocol) {
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DefaultFullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, SWITCHING_PROTOCOLS);
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res.headers().add(HttpHeaderNames.CONNECTION, HttpHeaderValues.UPGRADE);
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res.headers().add(HttpHeaderNames.UPGRADE, upgradeCodec.protocol());
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res.headers().add(HttpHeaderNames.UPGRADE, upgradeProtocol);
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res.headers().add(HttpHeaderNames.CONTENT_LENGTH, "0");
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return res;
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}
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@ -344,9 +352,9 @@ public class HttpServerUpgradeHandler extends HttpObjectAggregator {
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* Splits a comma-separated header value. The returned set is case-insensitive and contains each
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* part with whitespace removed.
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*/
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private static Set<CharSequence> splitHeader(CharSequence header) {
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StringBuilder builder = new StringBuilder(header.length());
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Set<CharSequence> protocols = new TreeSet<CharSequence>(AsciiString.CHARSEQUENCE_CASE_INSENSITIVE_ORDER);
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private static ArrayList<String> splitHeader(CharSequence header) {
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final StringBuilder builder = new StringBuilder(header.length());
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final ArrayList<String> protocols = new ArrayList<String>(4);
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for (int i = 0; i < header.length(); ++i) {
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char c = header.charAt(i);
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if (Character.isWhitespace(c)) {
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@ -31,7 +31,6 @@ import java.util.List;
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import static io.netty.handler.codec.base64.Base64Dialect.URL_SAFE;
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import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
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import static io.netty.handler.codec.http2.Http2CodecUtil.FRAME_HEADER_LENGTH;
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import static io.netty.handler.codec.http2.Http2CodecUtil.HTTP_UPGRADE_PROTOCOL_NAME;
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import static io.netty.handler.codec.http2.Http2CodecUtil.HTTP_UPGRADE_SETTINGS_HEADER;
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import static io.netty.handler.codec.http2.Http2CodecUtil.writeFrameHeader;
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import static io.netty.handler.codec.http2.Http2FrameTypes.SETTINGS;
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@ -72,11 +71,6 @@ public class Http2ServerUpgradeCodec implements HttpServerUpgradeHandler.Upgrade
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frameReader = new DefaultHttp2FrameReader();
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}
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@Override
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public String protocol() {
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return HTTP_UPGRADE_PROTOCOL_NAME;
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}
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@Override
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public Collection<String> requiredUpgradeHeaders() {
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return REQUIRED_UPGRADE_HEADERS;
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@ -19,21 +19,35 @@ package io.netty.example.http2.helloworld.server;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelInboundHandlerAdapter;
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import io.netty.channel.ChannelInitializer;
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import io.netty.channel.ChannelPipeline;
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import io.netty.channel.SimpleChannelInboundHandler;
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import io.netty.channel.socket.SocketChannel;
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import io.netty.handler.codec.http.HttpMessage;
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import io.netty.handler.codec.http.HttpServerCodec;
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import io.netty.handler.codec.http.HttpServerUpgradeHandler;
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import io.netty.handler.codec.http.HttpServerUpgradeHandler.UpgradeCodec;
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import io.netty.handler.codec.http.HttpServerUpgradeHandler.UpgradeCodecFactory;
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import io.netty.handler.codec.http2.Http2CodecUtil;
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import io.netty.handler.codec.http2.Http2ServerUpgradeCodec;
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import io.netty.handler.ssl.SslContext;
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import java.util.Collections;
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/**
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* Sets up the Netty pipeline for the example server. Depending on the endpoint config, sets up the
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* pipeline for NPN or cleartext HTTP upgrade to HTTP/2.
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*/
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public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
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private static final UpgradeCodecFactory upgradeCodecFactory = new UpgradeCodecFactory() {
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@Override
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public UpgradeCodec newUpgradeCodec(String protocol) {
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if (Http2CodecUtil.HTTP_UPGRADE_PROTOCOL_NAME.equals(protocol)) {
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return new Http2ServerUpgradeCodec(new HelloWorldHttp2Handler());
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} else {
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return null;
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}
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}
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};
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private final SslContext sslCtx;
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public Http2ServerInitializer(SslContext sslCtx) {
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@ -60,15 +74,12 @@ public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
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* Configure the pipeline for a cleartext upgrade from HTTP to HTTP/2.
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*/
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private static void configureClearText(SocketChannel ch) {
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HttpServerCodec sourceCodec = new HttpServerCodec();
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HttpServerUpgradeHandler.UpgradeCodec upgradeCodec =
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new Http2ServerUpgradeCodec(new HelloWorldHttp2Handler());
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HttpServerUpgradeHandler upgradeHandler =
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new HttpServerUpgradeHandler(sourceCodec, Collections.singletonList(upgradeCodec), 65536);
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final ChannelPipeline p = ch.pipeline();
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final HttpServerCodec sourceCodec = new HttpServerCodec();
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ch.pipeline().addLast(sourceCodec);
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ch.pipeline().addLast(upgradeHandler);
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ch.pipeline().addLast(new SimpleChannelInboundHandler<HttpMessage>() {
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p.addLast(sourceCodec);
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p.addLast(new HttpServerUpgradeHandler(sourceCodec, upgradeCodecFactory));
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p.addLast(new SimpleChannelInboundHandler<HttpMessage>() {
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@Override
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protected void channelRead0(ChannelHandlerContext ctx, HttpMessage msg) throws Exception {
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// If this handler is hit then no upgrade has been attempted and the client is just talking HTTP.
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@ -78,7 +89,8 @@ public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
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ctx.fireChannelRead(msg);
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}
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});
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ch.pipeline().addLast(new UserEventLogger());
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p.addLast(new UserEventLogger());
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}
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/**
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