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JDBC Driver for Google Cloud Spanner
/*
* Copyright 2015, gRPC Authors All rights reserved.
*
* 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 nl.topicus.jdbc.shaded.io.grpc.netty;
import static nl.topicus.jdbc.shaded.com.google.common.base.Preconditions.checkNotNull;
import static nl.topicus.jdbc.shaded.io.grpc.netty.GrpcSslContexts.NEXT_PROTOCOL_VERSIONS;
import nl.topicus.jdbc.shaded.com.google.common.annotations.VisibleForTesting;
import nl.topicus.jdbc.shaded.com.google.common.base.Preconditions;
import nl.topicus.jdbc.shaded.io.grpc.Attributes;
import nl.topicus.jdbc.shaded.io.grpc.Grpc;
import nl.topicus.jdbc.shaded.io.grpc.Internal;
import nl.topicus.jdbc.shaded.io.grpc.Status;
import nl.topicus.jdbc.shaded.io.grpc.internal.GrpcUtil;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelDuplexHandler;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelFuture;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelFutureListener;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelHandler;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelHandlerAdapter;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelHandlerContext;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelInboundHandler;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelInboundHandlerAdapter;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelPipeline;
import nl.topicus.jdbc.shaded.io.netty.channel.ChannelPromise;
import nl.topicus.jdbc.shaded.io.netty.handler.codec.http.DefaultHttpRequest;
import nl.topicus.jdbc.shaded.io.netty.handler.codec.http.HttpClientCodec;
import nl.topicus.jdbc.shaded.io.netty.handler.codec.http.HttpClientUpgradeHandler;
import nl.topicus.jdbc.shaded.io.netty.handler.codec.http.HttpMethod;
import nl.topicus.jdbc.shaded.io.netty.handler.codec.http.HttpVersion;
import nl.topicus.jdbc.shaded.io.netty.handler.codec.http2.Http2ClientUpgradeCodec;
import nl.topicus.jdbc.shaded.io.netty.handler.proxy.HttpProxyHandler;
import nl.topicus.jdbc.shaded.io.netty.handler.proxy.ProxyConnectionEvent;
import nl.topicus.jdbc.shaded.io.netty.handler.proxy.ProxyHandler;
import nl.topicus.jdbc.shaded.io.netty.handler.ssl.OpenSsl;
import nl.topicus.jdbc.shaded.io.netty.handler.ssl.OpenSslEngine;
import nl.topicus.jdbc.shaded.io.netty.handler.ssl.SslContext;
import nl.topicus.jdbc.shaded.io.netty.handler.ssl.SslHandler;
import nl.topicus.jdbc.shaded.io.netty.handler.ssl.SslHandshakeCompletionEvent;
import nl.topicus.jdbc.shaded.io.netty.util.AsciiString;
import nl.topicus.jdbc.shaded.io.netty.util.ReferenceCountUtil;
import java.net.SocketAddress;
import java.net.URI;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Queue;
import java.util.logging.Level;
import java.util.logging.Logger;
import nl.topicus.jdbc.shaded.javax.annotation.Nullable;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLParameters;
/**
* Common {@link ProtocolNegotiator}s used by gRPC.
*/
@Internal
public final class ProtocolNegotiators {
private static final Logger log = Logger.getLogger(ProtocolNegotiators.class.getName());
private ProtocolNegotiators() {
}
/**
* Create a server plaintext handler for gRPC.
*/
public static ProtocolNegotiator serverPlaintext() {
return new ProtocolNegotiator() {
@Override
public Handler newHandler(final GrpcHttp2ConnectionHandler handler) {
class PlaintextHandler extends ChannelHandlerAdapter implements Handler {
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
// Set sttributes before replace to be sure we pass it before accepting any requests.
handler.handleProtocolNegotiationCompleted(Attributes.newBuilder()
.set(Grpc.TRANSPORT_ATTR_REMOTE_ADDR, ctx.channel().remoteAddress())
.build());
// Just replace this handler with the gRPC handler.
ctx.pipeline().replace(this, null, handler);
}
@Override
public AsciiString scheme() {
return Utils.HTTP;
}
}
return new PlaintextHandler();
}
};
}
/**
* Create a server TLS handler for HTTP/2 capable of using ALPN/NPN.
*/
public static ProtocolNegotiator serverTls(final SslContext sslContext) {
Preconditions.checkNotNull(sslContext, "sslContext");
return new ProtocolNegotiator() {
@Override
public Handler newHandler(GrpcHttp2ConnectionHandler handler) {
return new ServerTlsHandler(sslContext, handler);
}
};
}
@VisibleForTesting
static final class ServerTlsHandler extends ChannelInboundHandlerAdapter
implements ProtocolNegotiator.Handler {
private final GrpcHttp2ConnectionHandler grpcHandler;
private final SslContext sslContext;
ServerTlsHandler(SslContext sslContext, GrpcHttp2ConnectionHandler grpcHandler) {
this.sslContext = sslContext;
this.grpcHandler = grpcHandler;
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
super.handlerAdded(ctx);
SSLEngine sslEngine = sslContext.newEngine(ctx.alloc());
ctx.pipeline().addFirst(new SslHandler(sslEngine, false));
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
fail(ctx, cause);
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (evt instanceof SslHandshakeCompletionEvent) {
SslHandshakeCompletionEvent handshakeEvent = (SslHandshakeCompletionEvent) evt;
if (handshakeEvent.isSuccess()) {
if (NEXT_PROTOCOL_VERSIONS.contains(sslHandler(ctx.pipeline()).applicationProtocol())) {
// Successfully negotiated the protocol.
// Notify about completion and pass down SSLSession in attributes.
grpcHandler.handleProtocolNegotiationCompleted(
Attributes.newBuilder()
.set(Grpc.TRANSPORT_ATTR_SSL_SESSION,
sslHandler(ctx.pipeline()).engine().getSession())
.set(Grpc.TRANSPORT_ATTR_REMOTE_ADDR, ctx.channel().remoteAddress())
.build());
// Replace this handler with the GRPC handler.
ctx.pipeline().replace(this, null, grpcHandler);
} else {
fail(ctx, new Exception(
"Failed protocol negotiation: Unable to find compatible protocol."));
}
} else {
fail(ctx, handshakeEvent.cause());
}
}
super.userEventTriggered(ctx, evt);
}
private SslHandler sslHandler(ChannelPipeline pipeline) {
return pipeline.get(SslHandler.class);
}
private void fail(ChannelHandlerContext ctx, Throwable exception) {
logSslEngineDetails(Level.FINE, ctx, "TLS negotiation failed for new client.", exception);
ctx.close();
}
@Override
public AsciiString scheme() {
return Utils.HTTPS;
}
}
/**
* Returns a {@link ProtocolNegotiator} that does HTTP CONNECT proxy negotiation.
*/
public static ProtocolNegotiator httpProxy(final SocketAddress proxyAddress,
final @Nullable String proxyUsername, final @Nullable String proxyPassword,
final ProtocolNegotiator negotiator) {
Preconditions.checkNotNull(proxyAddress, "proxyAddress");
Preconditions.checkNotNull(negotiator, "negotiator");
class ProxyNegotiator implements ProtocolNegotiator {
@Override
public Handler newHandler(GrpcHttp2ConnectionHandler http2Handler) {
HttpProxyHandler proxyHandler;
if (proxyUsername == null || proxyPassword == null) {
proxyHandler = new HttpProxyHandler(proxyAddress);
} else {
proxyHandler = new HttpProxyHandler(proxyAddress, proxyUsername, proxyPassword);
}
return new BufferUntilProxyTunnelledHandler(
proxyHandler, negotiator.newHandler(http2Handler));
}
}
return new ProxyNegotiator();
}
/**
* Buffers all writes until the HTTP CONNECT tunnel is established.
*/
static final class BufferUntilProxyTunnelledHandler extends AbstractBufferingHandler
implements ProtocolNegotiator.Handler {
private final ProtocolNegotiator.Handler originalHandler;
public BufferUntilProxyTunnelledHandler(
ProxyHandler proxyHandler, ProtocolNegotiator.Handler handler) {
super(proxyHandler, handler);
this.originalHandler = handler;
}
@Override
public AsciiString scheme() {
return originalHandler.scheme();
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (evt instanceof ProxyConnectionEvent) {
writeBufferedAndRemove(ctx);
}
super.userEventTriggered(ctx, evt);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
fail(ctx, unavailableException("Connection broken while trying to CONNECT through proxy"));
super.channelInactive(ctx);
}
@Override
public void close(ChannelHandlerContext ctx, ChannelPromise future) throws Exception {
if (ctx.channel().isActive()) { // This may be a notification that the socket was closed
fail(ctx, unavailableException("Channel closed while trying to CONNECT through proxy"));
}
super.close(ctx, future);
}
}
/**
* Returns a {@link ProtocolNegotiator} that ensures the pipeline is set up so that TLS will
* be negotiated, the {@code handler} is added and writes to the {@link nl.topicus.jdbc.shaded.io.netty.channel.Channel}
* may happen immediately, even before the TLS Handshake is complete.
*/
public static ProtocolNegotiator tls(SslContext sslContext, String authority) {
Preconditions.checkNotNull(sslContext, "sslContext");
URI uri = GrpcUtil.authorityToUri(Preconditions.checkNotNull(authority, "authority"));
String host;
int port;
if (uri.getHost() != null) {
host = uri.getHost();
port = uri.getPort();
} else {
/*
* Implementation note: We pick -1 as the port here rather than deriving it from the original
* socket address. The SSL engine doens't use this port number when contacting the remote
* server, but rather it is used for other things like SSL Session caching. When an invalid
* authority is provided (like "bad_cert"), picking the original port and passing it in would
* mean that the port might used under the assumption that it was correct. By using -1 here,
* it forces the SSL implementation to treat it as invalid.
*/
host = authority;
port = -1;
}
return new TlsNegotiator(sslContext, host, port);
}
static final class TlsNegotiator implements ProtocolNegotiator {
private final SslContext sslContext;
private final String host;
private final int port;
TlsNegotiator(SslContext sslContext, String host, int port) {
this.sslContext = checkNotNull(sslContext, "sslContext");
this.host = checkNotNull(host, "host");
this.port = port;
}
@VisibleForTesting
String getHost() {
return host;
}
@VisibleForTesting
int getPort() {
return port;
}
@Override
public Handler newHandler(GrpcHttp2ConnectionHandler handler) {
ChannelHandler sslBootstrap = new ChannelHandlerAdapter() {
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
SSLEngine sslEngine = sslContext.newEngine(ctx.alloc(), host, port);
SSLParameters sslParams = sslEngine.getSSLParameters();
sslParams.setEndpointIdentificationAlgorithm("HTTPS");
sslEngine.setSSLParameters(sslParams);
ctx.pipeline().replace(this, null, new SslHandler(sslEngine, false));
}
};
return new BufferUntilTlsNegotiatedHandler(sslBootstrap, handler);
}
}
/**
* Returns a {@link ProtocolNegotiator} used for upgrading to HTTP/2 from HTTP/1.x.
*/
public static ProtocolNegotiator plaintextUpgrade() {
return new PlaintextUpgradeNegotiator();
}
static final class PlaintextUpgradeNegotiator implements ProtocolNegotiator {
@Override
public Handler newHandler(GrpcHttp2ConnectionHandler handler) {
// Register the plaintext upgrader
Http2ClientUpgradeCodec upgradeCodec = new Http2ClientUpgradeCodec(handler);
HttpClientCodec httpClientCodec = new HttpClientCodec();
final HttpClientUpgradeHandler upgrader =
new HttpClientUpgradeHandler(httpClientCodec, upgradeCodec, 1000);
return new BufferingHttp2UpgradeHandler(upgrader);
}
}
/**
* Returns a {@link ChannelHandler} that ensures that the {@code handler} is added to the
* pipeline writes to the {@link nl.topicus.jdbc.shaded.io.netty.channel.Channel} may happen immediately, even before it
* is active.
*/
public static ProtocolNegotiator plaintext() {
return new PlaintextNegotiator();
}
static final class PlaintextNegotiator implements ProtocolNegotiator {
@Override
public Handler newHandler(GrpcHttp2ConnectionHandler handler) {
return new BufferUntilChannelActiveHandler(handler);
}
}
private static RuntimeException unavailableException(String msg) {
return Status.UNAVAILABLE.withDescription(msg).asRuntimeException();
}
@VisibleForTesting
static void logSslEngineDetails(Level level, ChannelHandlerContext ctx, String msg,
@Nullable Throwable t) {
if (!log.isLoggable(level)) {
return;
}
SslHandler sslHandler = ctx.pipeline().get(SslHandler.class);
SSLEngine engine = sslHandler.engine();
StringBuilder builder = new StringBuilder(msg);
builder.append("\nSSLEngine Details: [\n");
if (engine instanceof OpenSslEngine) {
builder.append(" OpenSSL, ");
builder.append("Version: 0x").append(Integer.toHexString(OpenSsl.version()));
builder.append(" (").append(OpenSsl.versionString()).append("), ");
builder.append("ALPN supported: ").append(OpenSsl.isAlpnSupported());
} else if (JettyTlsUtil.isJettyAlpnConfigured()) {
builder.append(" Jetty ALPN");
} else if (JettyTlsUtil.isJettyNpnConfigured()) {
builder.append(" Jetty NPN");
}
builder.append("\n TLS Protocol: ");
builder.append(engine.getSession().getProtocol());
builder.append("\n Application Protocol: ");
builder.append(sslHandler.applicationProtocol());
builder.append("\n Need Client Auth: " );
builder.append(engine.getNeedClientAuth());
builder.append("\n Want Client Auth: ");
builder.append(engine.getWantClientAuth());
builder.append("\n Supported protocols=");
builder.append(Arrays.toString(engine.getSupportedProtocols()));
builder.append("\n Enabled protocols=");
builder.append(Arrays.toString(engine.getEnabledProtocols()));
builder.append("\n Supported ciphers=");
builder.append(Arrays.toString(engine.getSupportedCipherSuites()));
builder.append("\n Enabled ciphers=");
builder.append(Arrays.toString(engine.getEnabledCipherSuites()));
builder.append("\n]");
log.log(level, builder.toString(), t);
}
/**
* Buffers all writes until either {@link #writeBufferedAndRemove(ChannelHandlerContext)} or
* {@link #fail(ChannelHandlerContext, Throwable)} is called. This handler allows us to
* write to a {@link nl.topicus.jdbc.shaded.io.netty.channel.Channel} before we are allowed to write to it officially
* i.e. before it's active or the TLS Handshake is complete.
*/
public abstract static class AbstractBufferingHandler extends ChannelDuplexHandler {
private ChannelHandler[] handlers;
private Queue bufferedWrites = new ArrayDeque();
private boolean writing;
private boolean flushRequested;
private Throwable failCause;
/**
* @param handlers the ChannelHandlers are added to the pipeline on channelRegistered and
* before this handler.
*/
protected AbstractBufferingHandler(ChannelHandler... handlers) {
this.handlers = handlers;
}
/**
* When this channel is registered, we will add all the ChannelHandlers passed into our
* constructor to the pipeline.
*/
@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
/**
* This check is necessary as a channel may be registered with different event loops during it
* lifetime and we only want to configure it once.
*/
if (handlers != null) {
for (ChannelHandler handler : handlers) {
ctx.pipeline().addBefore(ctx.name(), null, handler);
}
ChannelHandler handler0 = handlers[0];
ChannelHandlerContext handler0Ctx = ctx.pipeline().context(handlers[0]);
handlers = null;
if (handler0Ctx != null) { // The handler may have removed itself immediately
if (handler0 instanceof ChannelInboundHandler) {
((ChannelInboundHandler) handler0).channelRegistered(handler0Ctx);
} else {
handler0Ctx.fireChannelRegistered();
}
}
} else {
super.channelRegistered(ctx);
}
}
/**
* Do not rely on channel handlers to propagate exceptions to us.
* {@link NettyClientHandler} is an example of a class that does not propagate exceptions.
* Add a listener to the connect future directly and do appropriate error handling.
*/
@Override
public void connect(final ChannelHandlerContext ctx, SocketAddress remoteAddress,
SocketAddress localAddress, ChannelPromise promise) throws Exception {
super.connect(ctx, remoteAddress, localAddress, promise);
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
fail(ctx, future.cause());
}
}
});
}
/**
* If we encounter an exception, then notify all buffered writes that we failed.
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
fail(ctx, cause);
}
/**
* If this channel becomes inactive, then notify all buffered writes that we failed.
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
fail(ctx, unavailableException("Connection broken while performing protocol negotiation"));
super.channelInactive(ctx);
}
/**
* Buffers the write until either {@link #writeBufferedAndRemove(ChannelHandlerContext)} is
* called, or we have somehow failed. If we have already failed in the past, then the write
* will fail immediately.
*/
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
throws Exception {
/**
* This check handles a race condition between Channel.write (in the calling thread) and the
* removal of this handler (in the event loop thread).
* The problem occurs in e.g. this sequence:
* 1) [caller thread] The write method identifies the context for this handler
* 2) [event loop] This handler removes itself from the pipeline
* 3) [caller thread] The write method delegates to the invoker to call the write method in
* the event loop thread. When this happens, we identify that this handler has been
* removed with "bufferedWrites == null".
*/
if (failCause != null) {
promise.setFailure(failCause);
ReferenceCountUtil.release(msg);
} else if (bufferedWrites == null) {
super.write(ctx, msg, promise);
} else {
bufferedWrites.add(new ChannelWrite(msg, promise));
}
}
/**
* Calls to this method will not trigger an immediate flush. The flush will be deferred until
* {@link #writeBufferedAndRemove(ChannelHandlerContext)}.
*/
@Override
public void flush(ChannelHandlerContext ctx) {
/**
* Swallowing any flushes is not only an optimization but also required
* for the SslHandler to work correctly. If the SslHandler receives multiple
* flushes while the handshake is still ongoing, then the handshake "randomly"
* times out. Not sure at this point why this is happening. Doing a single flush
* seems to work but multiple flushes don't ...
*/
if (bufferedWrites == null) {
ctx.flush();
} else {
flushRequested = true;
}
}
/**
* If we are still performing protocol negotiation, then this will propagate failures to all
* buffered writes.
*/
@Override
public void close(ChannelHandlerContext ctx, ChannelPromise future) throws Exception {
if (ctx.channel().isActive()) { // This may be a notification that the socket was closed
fail(ctx, unavailableException("Channel closed while performing protocol negotiation"));
}
super.close(ctx, future);
}
/**
* Propagate failures to all buffered writes.
*/
protected final void fail(ChannelHandlerContext ctx, Throwable cause) {
if (failCause == null) {
failCause = cause;
}
if (bufferedWrites != null) {
while (!bufferedWrites.isEmpty()) {
ChannelWrite write = bufferedWrites.poll();
write.promise.setFailure(cause);
ReferenceCountUtil.release(write.msg);
}
bufferedWrites = null;
}
/**
* In case something goes wrong ensure that the channel gets closed as the
* NettyClientTransport relies on the channel's close future to get completed.
*/
ctx.close();
}
protected final void writeBufferedAndRemove(ChannelHandlerContext ctx) {
if (!ctx.channel().isActive() || writing) {
return;
}
// Make sure that method can't be reentered, so that the ordering
// in the queue can't be messed up.
writing = true;
while (!bufferedWrites.isEmpty()) {
ChannelWrite write = bufferedWrites.poll();
ctx.write(write.msg, write.promise);
}
assert bufferedWrites.isEmpty();
bufferedWrites = null;
if (flushRequested) {
ctx.flush();
}
// Removal has to happen last as the above writes will likely trigger
// new writes that have to be added to the end of queue in order to not
// mess up the ordering.
ctx.pipeline().remove(this);
}
private static class ChannelWrite {
Object msg;
ChannelPromise promise;
ChannelWrite(Object msg, ChannelPromise promise) {
this.msg = msg;
this.promise = promise;
}
}
}
/**
* Buffers all writes until the TLS Handshake is complete.
*/
private static class BufferUntilTlsNegotiatedHandler extends AbstractBufferingHandler
implements ProtocolNegotiator.Handler {
private final GrpcHttp2ConnectionHandler grpcHandler;
BufferUntilTlsNegotiatedHandler(
ChannelHandler bootstrapHandler, GrpcHttp2ConnectionHandler grpcHandler) {
super(bootstrapHandler, grpcHandler);
this.grpcHandler = grpcHandler;
}
@Override
public AsciiString scheme() {
return Utils.HTTPS;
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (evt instanceof SslHandshakeCompletionEvent) {
SslHandshakeCompletionEvent handshakeEvent = (SslHandshakeCompletionEvent) evt;
if (handshakeEvent.isSuccess()) {
SslHandler handler = ctx.pipeline().get(SslHandler.class);
if (NEXT_PROTOCOL_VERSIONS.contains(handler.applicationProtocol())) {
// Successfully negotiated the protocol.
logSslEngineDetails(Level.FINER, ctx, "TLS negotiation succeeded.", null);
// Successfully negotiated the protocol.
// Notify about completion and pass down SSLSession in attributes.
grpcHandler.handleProtocolNegotiationCompleted(
Attributes.newBuilder()
.set(Grpc.TRANSPORT_ATTR_SSL_SESSION, handler.engine().getSession())
.set(Grpc.TRANSPORT_ATTR_REMOTE_ADDR, ctx.channel().remoteAddress())
.build());
writeBufferedAndRemove(ctx);
} else {
Exception ex = new Exception(
"Failed ALPN negotiation: Unable to find compatible protocol.");
logSslEngineDetails(Level.FINE, ctx, "TLS negotiation failed.", ex);
fail(ctx, ex);
}
} else {
fail(ctx, handshakeEvent.cause());
}
}
super.userEventTriggered(ctx, evt);
}
}
/**
* Buffers all writes until the {@link nl.topicus.jdbc.shaded.io.netty.channel.Channel} is active.
*/
private static class BufferUntilChannelActiveHandler extends AbstractBufferingHandler
implements ProtocolNegotiator.Handler {
BufferUntilChannelActiveHandler(ChannelHandler... handlers) {
super(handlers);
}
@Override
public AsciiString scheme() {
return Utils.HTTP;
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) {
writeBufferedAndRemove(ctx);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
writeBufferedAndRemove(ctx);
super.channelActive(ctx);
}
}
/**
* Buffers all writes until the HTTP to HTTP/2 upgrade is complete.
*/
private static class BufferingHttp2UpgradeHandler extends AbstractBufferingHandler
implements ProtocolNegotiator.Handler {
BufferingHttp2UpgradeHandler(ChannelHandler... handlers) {
super(handlers);
}
@Override
public AsciiString scheme() {
return Utils.HTTP;
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
// Trigger the HTTP/1.1 plaintext upgrade protocol by issuing an HTTP request
// which causes the upgrade headers to be added
DefaultHttpRequest upgradeTrigger =
new DefaultHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "/");
ctx.writeAndFlush(upgradeTrigger);
super.channelActive(ctx);
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (evt == HttpClientUpgradeHandler.UpgradeEvent.UPGRADE_SUCCESSFUL) {
writeBufferedAndRemove(ctx);
} else if (evt == HttpClientUpgradeHandler.UpgradeEvent.UPGRADE_REJECTED) {
fail(ctx, unavailableException("HTTP/2 upgrade rejected"));
}
super.userEventTriggered(ctx, evt);
}
}
}