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;
031
032import org.apache.commons.logging.Log;
033import org.apache.commons.logging.LogFactory;
034import org.apache.http.Header;
035import org.apache.http.HttpException;
036import org.apache.http.NoHttpResponseException;
037import org.apache.http.annotation.Contract;
038import org.apache.http.annotation.ThreadingBehavior;
039import org.apache.http.client.HttpRequestRetryHandler;
040import org.apache.http.client.NonRepeatableRequestException;
041import org.apache.http.client.methods.CloseableHttpResponse;
042import org.apache.http.client.methods.HttpExecutionAware;
043import org.apache.http.client.methods.HttpRequestWrapper;
044import org.apache.http.client.protocol.HttpClientContext;
045import org.apache.http.conn.routing.HttpRoute;
046import org.apache.http.util.Args;
047
048/**
049 * Request executor in the request execution chain that is responsible
050 * for making a decision whether a request failed due to an I/O error
051 * should be re-executed.
052 * <p>
053 * Further responsibilities such as communication with the opposite
054 * endpoint is delegated to the next executor in the request execution
055 * chain.
056 * </p>
057 *
058 * @since 4.3
059 */
060@Contract(threading = ThreadingBehavior.IMMUTABLE_CONDITIONAL)
061public class RetryExec implements ClientExecChain {
062
063    private final Log log = LogFactory.getLog(getClass());
064
065    private final ClientExecChain requestExecutor;
066    private final HttpRequestRetryHandler retryHandler;
067
068    public RetryExec(
069            final ClientExecChain requestExecutor,
070            final HttpRequestRetryHandler retryHandler) {
071        Args.notNull(requestExecutor, "HTTP request executor");
072        Args.notNull(retryHandler, "HTTP request retry handler");
073        this.requestExecutor = requestExecutor;
074        this.retryHandler = retryHandler;
075    }
076
077    @Override
078    public CloseableHttpResponse execute(
079            final HttpRoute route,
080            final HttpRequestWrapper request,
081            final HttpClientContext context,
082            final HttpExecutionAware execAware) throws IOException, HttpException {
083        Args.notNull(route, "HTTP route");
084        Args.notNull(request, "HTTP request");
085        Args.notNull(context, "HTTP context");
086        final Header[] origheaders = request.getAllHeaders();
087        for (int execCount = 1;; execCount++) {
088            try {
089                return this.requestExecutor.execute(route, request, context, execAware);
090            } catch (final IOException ex) {
091                if (execAware != null && execAware.isAborted()) {
092                    this.log.debug("Request has been aborted");
093                    throw ex;
094                }
095                if (retryHandler.retryRequest(ex, execCount, context)) {
096                    if (this.log.isInfoEnabled()) {
097                        this.log.info("I/O exception ("+ ex.getClass().getName() +
098                                ") caught when processing request to "
099                                + route +
100                                ": "
101                                + ex.getMessage());
102                    }
103                    if (this.log.isDebugEnabled()) {
104                        this.log.debug(ex.getMessage(), ex);
105                    }
106                    if (!RequestEntityProxy.isRepeatable(request)) {
107                        this.log.debug("Cannot retry non-repeatable request");
108                        throw new NonRepeatableRequestException("Cannot retry request " +
109                                "with a non-repeatable request entity", ex);
110                    }
111                    request.setHeaders(origheaders);
112                    if (this.log.isInfoEnabled()) {
113                        this.log.info("Retrying request to " + route);
114                    }
115                } else {
116                    if (ex instanceof NoHttpResponseException) {
117                        final NoHttpResponseException updatedex = new NoHttpResponseException(
118                                route.getTargetHost().toHostString() + " failed to respond");
119                        updatedex.setStackTrace(ex.getStackTrace());
120                        throw updatedex;
121                    } else {
122                        throw ex;
123                    }
124                }
125            }
126        }
127    }
128
129}