/**
* The MIT License (MIT)
*
* Copyright (c) 2014-2017 Yegor Bugayenko
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package org.takes.tk;
import com.jcabi.http.request.JdkRequest;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.URI;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.takes.Request;
import org.takes.Response;
import org.takes.Take;
import org.takes.misc.EnglishLowerCase;
import org.takes.rq.RqHeaders;
import org.takes.rq.RqLengthAware;
import org.takes.rq.RqMethod;
import org.takes.rq.RqPrint;
import org.takes.rq.RqRequestLine;
import org.takes.rs.RsWithBody;
import org.takes.rs.RsWithHeaders;
import org.takes.rs.RsWithStatus;
/**
* Take that proxies requests to another destination.
*
* <p>The class is immutable and thread-safe.
*
* @author Dragan Bozanovic (bozanovicdr@gmail.com)
* @version $Id: 6e554ca81adbec88b10a98c62cf699a60688e8bb $
* @since 0.25
* @checkstyle ClassDataAbstractionCouplingCheck (500 lines)
*/
public final class TkProxy implements Take {
/**
* Target.
*/
private final URI target;
/**
* Label, to add to the HTTP header.
*/
private final String label;
/**
* Ctor.
* @param tgt Target to which requests are forwarded
*/
public TkProxy(final URI tgt) {
this(tgt, TkProxy.class.getName());
}
/**
* Ctor.
* @param tgt Target to which requests are forwarded
*/
public TkProxy(final String tgt) {
this(URI.create(tgt), TkProxy.class.getName());
}
/**
* Ctor.
* @param tgt Target to which requests are forwarded
* @param mark Marker (text label) to add to the HTTP header
*/
public TkProxy(final String tgt, final String mark) {
this(URI.create(tgt), mark);
}
/**
* Ctor.
*
* <p>The {@code target} parameter takes the destination URL
* to which requests are proxied. Some valid examples:</p>
*
* <ul>
* <li>{@code http://example.com}</li>
* <li>{@code http://www.example.com}</li>
* <li>{@code https://example.com:8080}</li>
* <li>{@code https://example.com/x/y}</li>
* </ul>
*
* @param tgt Target to which requests are forwarded
* @param mark Marker (text label) to add to the HTTP header
*/
public TkProxy(final URI tgt, final String mark) {
this.target = tgt;
this.label = mark;
}
@Override
public Response act(final Request req) throws IOException {
final String input = new RqRequestLine.Base(req).uri();
final URI output = this.target.resolve(URI.create(input));
return this.response(
input, output,
this.request(req, output).fetch()
);
}
/**
* Creates the request to be forwarded to the target host.
*
* @param req Original request
* @param dest Destination URL
* @return Request to be forwarded
* @throws IOException If some problem inside
*/
@SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
private com.jcabi.http.Request request(final Request req,
final URI dest) throws IOException {
final String method = new RqMethod.Base(req).method();
com.jcabi.http.Request proxied = new JdkRequest(dest).method(method);
final RqHeaders headers = new RqHeaders.Base(req);
for (final String name : headers.names()) {
if ("content-length".equals(new EnglishLowerCase(name).string())) {
continue;
}
if (TkProxy.isHost(name)) {
proxied = proxied.header(name, this.target);
continue;
}
for (final String value : headers.header(name)) {
proxied = proxied.header(name, value);
}
}
if (headers.header("Content-Length").iterator().hasNext()
|| headers.header("Transfer-Encoding").iterator().hasNext()) {
final ByteArrayOutputStream output = new ByteArrayOutputStream();
new RqPrint(new RqLengthAware(req)).printBody(output);
proxied = proxied.body().set(output.toByteArray()).back();
}
return proxied;
}
/**
* Creates the response received from the target host.
*
* @param home Home host
* @param dest Destination URL
* @param rsp Response received from the target host
* @return Response
*/
private Response response(final String home, final URI dest,
final com.jcabi.http.Response rsp) {
final Collection<String> hdrs = new LinkedList<>();
hdrs.add(
String.format(
"X-Takes-TkProxy: from %s to %s by %s",
home, dest, this.label
)
);
for (final Map.Entry<String, List<String>> entry
: rsp.headers().entrySet()) {
for (final String value : entry.getValue()) {
final String val;
if (TkProxy.isHost(entry.getKey())) {
val = this.target.toString();
} else {
val = value;
}
hdrs.add(String.format("%s: %s", entry.getKey(), val));
}
}
return new RsWithStatus(
new RsWithBody(
new RsWithHeaders(hdrs),
rsp.binary()
),
rsp.status(),
rsp.reason()
);
}
/**
* Checks whether the provided argument is a "Host" header name.
* @param header Header name
* @return Returns {@code true} if {@code header} parameter is a "Host"
* header name, {@code false} otherwise
*/
private static boolean isHost(final String header) {
return "host".equals(new EnglishLowerCase(header).string());
}
}