ClassicReverseProxyExample.java
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing,
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* KIND, either express or implied. See the License for the
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* under the License.
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*
* This software consists of voluntary contributions made by many
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package org.apache.hc.core5.http.examples;
import java.io.IOException;
import java.net.SocketException;
import java.net.SocketTimeoutException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.apache.hc.core5.http.ClassicHttpRequest;
import org.apache.hc.core5.http.ClassicHttpResponse;
import org.apache.hc.core5.http.ConnectionClosedException;
import org.apache.hc.core5.http.ExceptionListener;
import org.apache.hc.core5.http.Header;
import org.apache.hc.core5.http.HttpConnection;
import org.apache.hc.core5.http.HttpException;
import org.apache.hc.core5.http.HttpHeaders;
import org.apache.hc.core5.http.HttpHost;
import org.apache.hc.core5.http.HttpRequest;
import org.apache.hc.core5.http.HttpResponse;
import org.apache.hc.core5.http.impl.Http1StreamListener;
import org.apache.hc.core5.http.impl.bootstrap.HttpRequester;
import org.apache.hc.core5.http.impl.bootstrap.HttpServer;
import org.apache.hc.core5.http.impl.bootstrap.RequesterBootstrap;
import org.apache.hc.core5.http.impl.bootstrap.ServerBootstrap;
import org.apache.hc.core5.http.io.HttpRequestHandler;
import org.apache.hc.core5.http.message.BasicClassicHttpRequest;
import org.apache.hc.core5.http.protocol.HttpContext;
import org.apache.hc.core5.http.protocol.HttpCoreContext;
import org.apache.hc.core5.io.CloseMode;
import org.apache.hc.core5.pool.ConnPoolListener;
import org.apache.hc.core5.pool.ConnPoolStats;
import org.apache.hc.core5.pool.PoolStats;
import org.apache.hc.core5.util.TextUtils;
import org.apache.hc.core5.util.TimeValue;
import org.apache.hc.core5.util.Timeout;
/**
* Example of embedded HTTP/1.1 reverse proxy using classic I/O.
*/
public class ClassicReverseProxyExample {
public static void main(final String[] args) throws Exception {
if (args.length < 1) {
System.out.println("Usage: <hostname[:port]> [listener port]");
System.exit(1);
}
final HttpHost targetHost = HttpHost.create(args[0]);
int port = 8080;
if (args.length > 1) {
port = Integer.parseInt(args[1]);
}
System.out.println("Reverse proxy to " + targetHost);
final HttpRequester requester = RequesterBootstrap.bootstrap()
.setStreamListener(new Http1StreamListener() {
@Override
public void onRequestHead(final HttpConnection connection, final HttpRequest request) {
System.out.println("[proxy->origin] " + Thread.currentThread() + " " +
request.getMethod() + " " + request.getRequestUri());
}
@Override
public void onResponseHead(final HttpConnection connection, final HttpResponse response) {
System.out.println("[proxy<-origin] " + Thread.currentThread() + " status " + response.getCode());
}
@Override
public void onExchangeComplete(final HttpConnection connection, final boolean keepAlive) {
System.out.println("[proxy<-origin] " + Thread.currentThread() + " exchange completed; " +
"connection " + (keepAlive ? "kept alive" : "cannot be kept alive"));
}
})
.setConnPoolListener(new ConnPoolListener<HttpHost>() {
@Override
public void onLease(final HttpHost route, final ConnPoolStats<HttpHost> connPoolStats) {
final StringBuilder buf = new StringBuilder();
buf.append("[proxy->origin] ").append(Thread.currentThread()).append(" connection leased ").append(route);
System.out.println(buf);
}
@Override
public void onRelease(final HttpHost route, final ConnPoolStats<HttpHost> connPoolStats) {
final StringBuilder buf = new StringBuilder();
buf.append("[proxy->origin] ").append(Thread.currentThread()).append(" connection released ").append(route);
final PoolStats totals = connPoolStats.getTotalStats();
buf.append("; total kept alive: ").append(totals.getAvailable()).append("; ");
buf.append("total allocated: ").append(totals.getLeased() + totals.getAvailable());
buf.append(" of ").append(totals.getMax());
System.out.println(buf);
}
})
.create();
final HttpServer server = ServerBootstrap.bootstrap()
.setListenerPort(port)
.setStreamListener(new Http1StreamListener() {
@Override
public void onRequestHead(final HttpConnection connection, final HttpRequest request) {
System.out.println("[client->proxy] " + Thread.currentThread() + " " +
request.getMethod() + " " + request.getRequestUri());
}
@Override
public void onResponseHead(final HttpConnection connection, final HttpResponse response) {
System.out.println("[client<-proxy] " + Thread.currentThread() + " status " + response.getCode());
}
@Override
public void onExchangeComplete(final HttpConnection connection, final boolean keepAlive) {
System.out.println("[client<-proxy] " + Thread.currentThread() + " exchange completed; " +
"connection " + (keepAlive ? "kept alive" : "cannot be kept alive"));
}
})
.setExceptionListener(new ExceptionListener() {
@Override
public void onError(final Exception ex) {
if (ex instanceof SocketException) {
System.out.println("[client->proxy] " + Thread.currentThread() + " " + ex.getMessage());
} else {
System.out.println("[client->proxy] " + Thread.currentThread() + " " + ex.getMessage());
ex.printStackTrace(System.out);
}
}
@Override
public void onError(final HttpConnection connection, final Exception ex) {
if (ex instanceof SocketTimeoutException) {
System.out.println("[client->proxy] " + Thread.currentThread() + " time out");
} else if (ex instanceof SocketException || ex instanceof ConnectionClosedException) {
System.out.println("[client->proxy] " + Thread.currentThread() + " " + ex.getMessage());
} else {
System.out.println("[client->proxy] " + Thread.currentThread() + " " + ex.getMessage());
ex.printStackTrace(System.out);
}
}
})
.register("*", new ProxyHandler(targetHost, requester))
.create();
server.start();
Runtime.getRuntime().addShutdownHook(new Thread(() -> {
server.close(CloseMode.GRACEFUL);
requester.close(CloseMode.GRACEFUL);
}));
System.out.println("Listening on port " + port);
server.awaitTermination(TimeValue.MAX_VALUE);
}
private final static Set<String> HOP_BY_HOP = Collections.unmodifiableSet(new HashSet<>(Arrays.asList(
TextUtils.toLowerCase(HttpHeaders.HOST),
TextUtils.toLowerCase(HttpHeaders.CONTENT_LENGTH),
TextUtils.toLowerCase(HttpHeaders.TRANSFER_ENCODING),
TextUtils.toLowerCase(HttpHeaders.CONNECTION),
TextUtils.toLowerCase(HttpHeaders.KEEP_ALIVE),
TextUtils.toLowerCase(HttpHeaders.PROXY_AUTHENTICATE),
TextUtils.toLowerCase(HttpHeaders.TE),
TextUtils.toLowerCase(HttpHeaders.TRAILER),
TextUtils.toLowerCase(HttpHeaders.UPGRADE))));
static class ProxyHandler implements HttpRequestHandler {
private final HttpHost targetHost;
private final HttpRequester requester;
public ProxyHandler(
final HttpHost targetHost,
final HttpRequester requester) {
super();
this.targetHost = targetHost;
this.requester = requester;
}
@Override
public void handle(
final ClassicHttpRequest incomingRequest,
final ClassicHttpResponse outgoingResponse,
final HttpContext serverContext) throws HttpException, IOException {
final HttpCoreContext clientContext = HttpCoreContext.create();
final ClassicHttpRequest outgoingRequest = new BasicClassicHttpRequest(
incomingRequest.getMethod(),
targetHost,
incomingRequest.getPath());
for (final Iterator<Header> it = incomingRequest.headerIterator(); it.hasNext(); ) {
final Header header = it.next();
if (!HOP_BY_HOP.contains(TextUtils.toLowerCase(header.getName()))) {
outgoingRequest.addHeader(header);
}
}
outgoingRequest.setEntity(incomingRequest.getEntity());
final ClassicHttpResponse incomingResponse = requester.execute(
targetHost, outgoingRequest, Timeout.ofMinutes(1), clientContext);
outgoingResponse.setCode(incomingResponse.getCode());
for (final Iterator<Header> it = incomingResponse.headerIterator(); it.hasNext(); ) {
final Header header = it.next();
if (!HOP_BY_HOP.contains(TextUtils.toLowerCase(header.getName()))) {
outgoingResponse.addHeader(header);
}
}
outgoingResponse.setEntity(incomingResponse.getEntity());
}
}
}