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Apache HttpComponents Client
/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* 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
* "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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
*
* The restriction on automatic redirection of POST methods can be relaxed by using
* {@link LaxRedirectStrategy} instead of {@link DefaultRedirectStrategy}.
*
*
* @see LaxRedirectStrategy
* @since 4.1
*/
@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class DefaultRedirectStrategy implements RedirectStrategy {
private final Log log = LogFactory.getLog(getClass());
/**
* @deprecated (4.3) use {@link org.apache.http.client.protocol.HttpClientContext#REDIRECT_LOCATIONS}.
*/
@Deprecated
public static final String REDIRECT_LOCATIONS = "http.protocol.redirect-locations";
public static final DefaultRedirectStrategy INSTANCE = new DefaultRedirectStrategy();
/**
* Redirectable methods.
*/
private static final String[] REDIRECT_METHODS = new String[] {
HttpGet.METHOD_NAME,
HttpHead.METHOD_NAME
};
public DefaultRedirectStrategy() {
super();
}
@Override
public boolean isRedirected(
final HttpRequest request,
final HttpResponse response,
final HttpContext context) throws ProtocolException {
Args.notNull(request, "HTTP request");
Args.notNull(response, "HTTP response");
final int statusCode = response.getStatusLine().getStatusCode();
final String method = request.getRequestLine().getMethod();
final Header locationHeader = response.getFirstHeader("location");
switch (statusCode) {
case HttpStatus.SC_MOVED_TEMPORARILY:
return isRedirectable(method) && locationHeader != null;
case HttpStatus.SC_MOVED_PERMANENTLY:
case HttpStatus.SC_TEMPORARY_REDIRECT:
return isRedirectable(method);
case HttpStatus.SC_SEE_OTHER:
return true;
default:
return false;
} //end of switch
}
public URI getLocationURI(
final HttpRequest request,
final HttpResponse response,
final HttpContext context) throws ProtocolException {
Args.notNull(request, "HTTP request");
Args.notNull(response, "HTTP response");
Args.notNull(context, "HTTP context");
final HttpClientContext clientContext = HttpClientContext.adapt(context);
//get the location header to find out where to redirect to
final Header locationHeader = response.getFirstHeader("location");
if (locationHeader == null) {
// got a redirect response, but no location header
throw new ProtocolException(
"Received redirect response " + response.getStatusLine()
+ " but no location header");
}
final String location = locationHeader.getValue();
if (this.log.isDebugEnabled()) {
this.log.debug("Redirect requested to location '" + location + "'");
}
final RequestConfig config = clientContext.getRequestConfig();
URI uri = createLocationURI(location);
// rfc2616 demands the location value be a complete URI
// Location = "Location" ":" absoluteURI
try {
if (!uri.isAbsolute()) {
if (!config.isRelativeRedirectsAllowed()) {
throw new ProtocolException("Relative redirect location '"
+ uri + "' not allowed");
}
// Adjust location URI
final HttpHost target = clientContext.getTargetHost();
Asserts.notNull(target, "Target host");
final URI requestURI = new URI(request.getRequestLine().getUri());
final URI absoluteRequestURI = URIUtils.rewriteURI(requestURI, target, false);
uri = URIUtils.resolve(absoluteRequestURI, uri);
}
} catch (final URISyntaxException ex) {
throw new ProtocolException(ex.getMessage(), ex);
}
RedirectLocations redirectLocations = (RedirectLocations) clientContext.getAttribute(
HttpClientContext.REDIRECT_LOCATIONS);
if (redirectLocations == null) {
redirectLocations = new RedirectLocations();
context.setAttribute(HttpClientContext.REDIRECT_LOCATIONS, redirectLocations);
}
if (!config.isCircularRedirectsAllowed()) {
if (redirectLocations.contains(uri)) {
throw new CircularRedirectException("Circular redirect to '" + uri + "'");
}
}
redirectLocations.add(uri);
return uri;
}
/**
* @since 4.1
*/
protected URI createLocationURI(final String location) throws ProtocolException {
try {
final URIBuilder b = new URIBuilder(new URI(location).normalize());
final String host = b.getHost();
if (host != null) {
b.setHost(host.toLowerCase(Locale.ROOT));
}
final String path = b.getPath();
if (TextUtils.isEmpty(path)) {
b.setPath("/");
}
return b.build();
} catch (final URISyntaxException ex) {
throw new ProtocolException("Invalid redirect URI: " + location, ex);
}
}
/**
* @since 4.2
*/
protected boolean isRedirectable(final String method) {
for (final String m: REDIRECT_METHODS) {
if (m.equalsIgnoreCase(method)) {
return true;
}
}
return false;
}
@Override
public HttpUriRequest getRedirect(
final HttpRequest request,
final HttpResponse response,
final HttpContext context) throws ProtocolException {
final URI uri = getLocationURI(request, response, context);
final String method = request.getRequestLine().getMethod();
if (method.equalsIgnoreCase(HttpHead.METHOD_NAME)) {
return new HttpHead(uri);
} else if (method.equalsIgnoreCase(HttpGet.METHOD_NAME)) {
return new HttpGet(uri);
} else {
final int status = response.getStatusLine().getStatusCode();
if (status == HttpStatus.SC_TEMPORARY_REDIRECT) {
return RequestBuilder.copy(request).setUri(uri).build();
} else {
return new HttpGet(uri);
}
}
}
}