001/*
002 * ====================================================================
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *   http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing,
014 * software distributed under the License is distributed on an
015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
016 * KIND, either express or implied.  See the License for the
017 * specific language governing permissions and limitations
018 * under the License.
019 * ====================================================================
020 *
021 * This software consists of voluntary contributions made by many
022 * individuals on behalf of the Apache Software Foundation.  For more
023 * information on the Apache Software Foundation, please see
024 * <http://www.apache.org/>.
025 *
026 */
027
028package org.apache.http.impl.execchain;
029
030import java.io.IOException;
031import java.net.URI;
032import java.util.List;
033
034import org.apache.commons.logging.Log;
035import org.apache.commons.logging.LogFactory;
036import org.apache.http.HttpEntityEnclosingRequest;
037import org.apache.http.HttpException;
038import org.apache.http.HttpHost;
039import org.apache.http.HttpRequest;
040import org.apache.http.ProtocolException;
041import org.apache.http.annotation.Contract;
042import org.apache.http.annotation.ThreadingBehavior;
043import org.apache.http.auth.AuthScheme;
044import org.apache.http.auth.AuthState;
045import org.apache.http.client.RedirectException;
046import org.apache.http.client.RedirectStrategy;
047import org.apache.http.client.config.RequestConfig;
048import org.apache.http.client.methods.CloseableHttpResponse;
049import org.apache.http.client.methods.HttpExecutionAware;
050import org.apache.http.client.methods.HttpRequestWrapper;
051import org.apache.http.client.protocol.HttpClientContext;
052import org.apache.http.client.utils.URIUtils;
053import org.apache.http.conn.routing.HttpRoute;
054import org.apache.http.conn.routing.HttpRoutePlanner;
055import org.apache.http.util.Args;
056import org.apache.http.util.EntityUtils;
057
058/**
059 * Request executor in the request execution chain that is responsible
060 * for handling of request redirects.
061 * <p>
062 * Further responsibilities such as communication with the opposite
063 * endpoint is delegated to the next executor in the request execution
064 * chain.
065 * </p>
066 *
067 * @since 4.3
068 */
069@Contract(threading = ThreadingBehavior.IMMUTABLE_CONDITIONAL)
070public class RedirectExec implements ClientExecChain {
071
072    private final Log log = LogFactory.getLog(getClass());
073
074    private final ClientExecChain requestExecutor;
075    private final RedirectStrategy redirectStrategy;
076    private final HttpRoutePlanner routePlanner;
077
078    public RedirectExec(
079            final ClientExecChain requestExecutor,
080            final HttpRoutePlanner routePlanner,
081            final RedirectStrategy redirectStrategy) {
082        super();
083        Args.notNull(requestExecutor, "HTTP client request executor");
084        Args.notNull(routePlanner, "HTTP route planner");
085        Args.notNull(redirectStrategy, "HTTP redirect strategy");
086        this.requestExecutor = requestExecutor;
087        this.routePlanner = routePlanner;
088        this.redirectStrategy = redirectStrategy;
089    }
090
091    @Override
092    public CloseableHttpResponse execute(
093            final HttpRoute route,
094            final HttpRequestWrapper request,
095            final HttpClientContext context,
096            final HttpExecutionAware execAware) throws IOException, HttpException {
097        Args.notNull(route, "HTTP route");
098        Args.notNull(request, "HTTP request");
099        Args.notNull(context, "HTTP context");
100
101        final List<URI> redirectLocations = context.getRedirectLocations();
102        if (redirectLocations != null) {
103            redirectLocations.clear();
104        }
105
106        final RequestConfig config = context.getRequestConfig();
107        final int maxRedirects = config.getMaxRedirects() > 0 ? config.getMaxRedirects() : 50;
108        HttpRoute currentRoute = route;
109        HttpRequestWrapper currentRequest = request;
110        for (int redirectCount = 0;;) {
111            final CloseableHttpResponse response = requestExecutor.execute(
112                    currentRoute, currentRequest, context, execAware);
113            try {
114                if (config.isRedirectsEnabled() &&
115                        this.redirectStrategy.isRedirected(currentRequest.getOriginal(), response, context)) {
116
117                    if (redirectCount >= maxRedirects) {
118                        throw new RedirectException("Maximum redirects ("+ maxRedirects + ") exceeded");
119                    }
120                    redirectCount++;
121
122                    final HttpRequest redirect = this.redirectStrategy.getRedirect(
123                            currentRequest.getOriginal(), response, context);
124                    if (!redirect.headerIterator().hasNext()) {
125                        final HttpRequest original = request.getOriginal();
126                        redirect.setHeaders(original.getAllHeaders());
127                    }
128                    currentRequest = HttpRequestWrapper.wrap(redirect);
129
130                    if (currentRequest instanceof HttpEntityEnclosingRequest) {
131                        RequestEntityProxy.enhance((HttpEntityEnclosingRequest) currentRequest);
132                    }
133
134                    final URI uri = currentRequest.getURI();
135                    final HttpHost newTarget = URIUtils.extractHost(uri);
136                    if (newTarget == null) {
137                        throw new ProtocolException("Redirect URI does not specify a valid host name: " +
138                                uri);
139                    }
140
141                    // Reset virtual host and auth states if redirecting to another host
142                    if (!currentRoute.getTargetHost().equals(newTarget)) {
143                        final AuthState targetAuthState = context.getTargetAuthState();
144                        if (targetAuthState != null) {
145                            this.log.debug("Resetting target auth state");
146                            targetAuthState.reset();
147                        }
148                        final AuthState proxyAuthState = context.getProxyAuthState();
149                        if (proxyAuthState != null) {
150                            final AuthScheme authScheme = proxyAuthState.getAuthScheme();
151                            if (authScheme != null && authScheme.isConnectionBased()) {
152                                this.log.debug("Resetting proxy auth state");
153                                proxyAuthState.reset();
154                            }
155                        }
156                    }
157
158                    currentRoute = this.routePlanner.determineRoute(newTarget, currentRequest, context);
159                    if (this.log.isDebugEnabled()) {
160                        this.log.debug("Redirecting to '" + uri + "' via " + currentRoute);
161                    }
162                    EntityUtils.consume(response.getEntity());
163                    response.close();
164                } else {
165                    return response;
166                }
167            } catch (final RuntimeException ex) {
168                response.close();
169                throw ex;
170            } catch (final IOException ex) {
171                response.close();
172                throw ex;
173            } catch (final HttpException ex) {
174                // Protocol exception related to a direct.
175                // The underlying connection may still be salvaged.
176                try {
177                    EntityUtils.consume(response.getEntity());
178                } catch (final IOException ioex) {
179                    this.log.debug("I/O error while releasing connection", ioex);
180                } finally {
181                    response.close();
182                }
183                throw ex;
184            }
185        }
186    }
187
188}