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.protocol;
029
030import java.io.IOException;
031
032import org.apache.http.HttpException;
033import org.apache.http.HttpRequest;
034import org.apache.http.HttpRequestInterceptor;
035import org.apache.http.annotation.ThreadingBehavior;
036import org.apache.http.annotation.Contract;
037import org.apache.http.util.Args;
038
039/**
040 * RequestConnControl is responsible for adding {@code Connection} header
041 * to the outgoing requests, which is essential for managing persistence of
042 * {@code HTTP/1.0} connections. This interceptor is recommended for
043 * client side protocol processors.
044 *
045 * @since 4.0
046 */
047@Contract(threading = ThreadingBehavior.IMMUTABLE)
048public class RequestConnControl implements HttpRequestInterceptor {
049
050    public RequestConnControl() {
051        super();
052    }
053
054    @Override
055    public void process(final HttpRequest request, final HttpContext context)
056            throws HttpException, IOException {
057        Args.notNull(request, "HTTP request");
058
059        final String method = request.getRequestLine().getMethod();
060        if (method.equalsIgnoreCase("CONNECT")) {
061            return;
062        }
063
064        if (!request.containsHeader(HTTP.CONN_DIRECTIVE)) {
065            // Default policy is to keep connection alive
066            // whenever possible
067            request.addHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_KEEP_ALIVE);
068        }
069    }
070
071}