Add back missing HttpTunnelingServlet. See #148
This commit is contained in:
Norman Maurer
parent
16fada5c23
commit
d0a962422e
@ -35,6 +35,14 @@
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<artifactId>netty-codec-http</artifactId>
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<version>${project.version}</version>
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</dependency>
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<!-- Servlet API - completely optional -->
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<!-- Used for HTTP tunneling transport -->
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<dependency>
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<groupId>javax.servlet</groupId>
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<artifactId>servlet-api</artifactId>
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<optional>true</optional>
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</dependency>
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</dependencies>
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</project>
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@ -0,0 +1,240 @@
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/*
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* Copyright 2011 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.channel.socket.http;
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import java.io.EOFException;
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import java.io.IOException;
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import java.io.PushbackInputStream;
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import java.net.SocketAddress;
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import javax.servlet.ServletConfig;
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import javax.servlet.ServletException;
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import javax.servlet.ServletOutputStream;
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import javax.servlet.http.HttpServlet;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import io.netty.buffer.ChannelBuffer;
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import io.netty.buffer.ChannelBuffers;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelFactory;
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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.channel.ChannelPipeline;
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import io.netty.channel.Channels;
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import io.netty.channel.ExceptionEvent;
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import io.netty.channel.MessageEvent;
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import io.netty.channel.SimpleChannelUpstreamHandler;
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import io.netty.channel.local.DefaultLocalClientChannelFactory;
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import io.netty.channel.local.LocalAddress;
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import io.netty.handler.codec.http.HttpHeaders;
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import io.netty.logging.InternalLogger;
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import io.netty.logging.InternalLoggerFactory;
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/**
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* An {@link HttpServlet} that proxies an incoming data to the actual server
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* and vice versa. Please refer to the
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* <a href="package-summary.html#package_description">package summary</a> for
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* the detailed usage.
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* @apiviz.landmark
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*/
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public class HttpTunnelingServlet extends HttpServlet {
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private static final long serialVersionUID = 4259910275899756070L;
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private static final String ENDPOINT = "endpoint";
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static final InternalLogger logger = InternalLoggerFactory.getInstance(HttpTunnelingServlet.class);
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private volatile SocketAddress remoteAddress;
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private volatile ChannelFactory channelFactory;
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@Override
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public void init() throws ServletException {
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ServletConfig config = getServletConfig();
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String endpoint = config.getInitParameter(ENDPOINT);
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if (endpoint == null) {
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throw new ServletException("init-param '" + ENDPOINT + "' must be specified.");
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}
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try {
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remoteAddress = parseEndpoint(endpoint.trim());
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} catch (ServletException e) {
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throw e;
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} catch (Exception e) {
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throw new ServletException("Failed to parse an endpoint.", e);
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}
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try {
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channelFactory = createChannelFactory(remoteAddress);
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} catch (ServletException e) {
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throw e;
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} catch (Exception e) {
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throw new ServletException("Failed to create a channel factory.", e);
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}
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// Stuff for testing purpose
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//ServerBootstrap b = new ServerBootstrap(new DefaultLocalServerChannelFactory());
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//b.getPipeline().addLast("logger", new LoggingHandler(getClass(), InternalLogLevel.INFO, true));
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//b.getPipeline().addLast("handler", new EchoHandler());
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//b.bind(remoteAddress);
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}
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protected SocketAddress parseEndpoint(String endpoint) throws Exception {
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if (endpoint.startsWith("local:")) {
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return new LocalAddress(endpoint.substring(6).trim());
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} else {
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throw new ServletException(
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"Invalid or unknown endpoint: " + endpoint);
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}
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}
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protected ChannelFactory createChannelFactory(SocketAddress remoteAddress) throws Exception {
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if (remoteAddress instanceof LocalAddress) {
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return new DefaultLocalClientChannelFactory();
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} else {
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throw new ServletException(
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"Unsupported remote address type: " +
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remoteAddress.getClass().getName());
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}
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}
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@Override
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public void destroy() {
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try {
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destroyChannelFactory(channelFactory);
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} catch (Exception e) {
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logger.warn("Failed to destroy a channel factory.", e);
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}
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}
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protected void destroyChannelFactory(ChannelFactory factory) throws Exception {
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factory.releaseExternalResources();
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}
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@Override
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protected void service(HttpServletRequest req, HttpServletResponse res)
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throws ServletException, IOException {
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if (!"POST".equalsIgnoreCase(req.getMethod())) {
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logger.warn("Unallowed method: " + req.getMethod());
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res.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
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return;
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}
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final ChannelPipeline pipeline = Channels.pipeline();
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final ServletOutputStream out = res.getOutputStream();
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final OutboundConnectionHandler handler = new OutboundConnectionHandler(out);
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pipeline.addLast("handler", handler);
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Channel channel = channelFactory.newChannel(pipeline);
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ChannelFuture future = channel.connect(remoteAddress).awaitUninterruptibly();
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if (!future.isSuccess()) {
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Throwable cause = future.getCause();
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logger.warn("Endpoint unavailable: " + cause.getMessage(), cause);
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res.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
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return;
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}
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ChannelFuture lastWriteFuture = null;
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try {
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res.setStatus(HttpServletResponse.SC_OK);
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res.setHeader(HttpHeaders.Names.CONTENT_TYPE, "application/octet-stream");
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res.setHeader(HttpHeaders.Names.CONTENT_TRANSFER_ENCODING, HttpHeaders.Values.BINARY);
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// Initiate chunked encoding by flushing the headers.
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out.flush();
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PushbackInputStream in =
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new PushbackInputStream(req.getInputStream());
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while (channel.isConnected()) {
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ChannelBuffer buffer;
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try {
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buffer = read(in);
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} catch (EOFException e) {
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break;
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}
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if (buffer == null) {
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break;
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}
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lastWriteFuture = channel.write(buffer);
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}
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} finally {
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if (lastWriteFuture == null) {
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channel.close();
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} else {
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lastWriteFuture.addListener(ChannelFutureListener.CLOSE);
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}
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}
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}
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private static ChannelBuffer read(PushbackInputStream in) throws IOException {
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byte[] buf;
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int readBytes;
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int bytesToRead = in.available();
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if (bytesToRead > 0) {
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buf = new byte[bytesToRead];
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readBytes = in.read(buf);
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} else if (bytesToRead == 0) {
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int b = in.read();
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if (b < 0 || in.available() < 0) {
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return null;
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}
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in.unread(b);
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bytesToRead = in.available();
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buf = new byte[bytesToRead];
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readBytes = in.read(buf);
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} else {
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return null;
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}
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assert readBytes > 0;
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ChannelBuffer buffer;
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if (readBytes == buf.length) {
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buffer = ChannelBuffers.wrappedBuffer(buf);
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} else {
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// A rare case, but it sometimes happen.
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buffer = ChannelBuffers.wrappedBuffer(buf, 0, readBytes);
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}
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return buffer;
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}
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private static final class OutboundConnectionHandler extends SimpleChannelUpstreamHandler {
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private final ServletOutputStream out;
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public OutboundConnectionHandler(ServletOutputStream out) {
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this.out = out;
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}
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@Override
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public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
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ChannelBuffer buffer = (ChannelBuffer) e.getMessage();
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synchronized (this) {
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buffer.readBytes(out, buffer.readableBytes());
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out.flush();
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}
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}
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@Override
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public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
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logger.warn("Unexpected exception while HTTP tunneling", e.getCause());
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e.getChannel().close();
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}
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}
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}
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