| /* |
| * ==================================================================== |
| * 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 |
| * <http://www.apache.org/>. |
| * |
| */ |
| |
| package org.apache.hc.core5.http.impl; |
| |
| import java.util.Iterator; |
| |
| import org.apache.hc.core5.annotation.Contract; |
| import org.apache.hc.core5.annotation.ThreadingBehavior; |
| import org.apache.hc.core5.http.ConnectionReuseStrategy; |
| import org.apache.hc.core5.http.Header; |
| import org.apache.hc.core5.http.HeaderElements; |
| import org.apache.hc.core5.http.HttpHeaders; |
| import org.apache.hc.core5.http.HttpRequest; |
| import org.apache.hc.core5.http.HttpResponse; |
| import org.apache.hc.core5.http.HttpStatus; |
| import org.apache.hc.core5.http.HttpVersion; |
| import org.apache.hc.core5.http.ProtocolVersion; |
| import org.apache.hc.core5.http.message.BasicTokenIterator; |
| import org.apache.hc.core5.http.message.MessageSupport; |
| import org.apache.hc.core5.http.protocol.HttpContext; |
| import org.apache.hc.core5.util.Args; |
| |
| /** |
| * Default implementation of a strategy deciding about connection re-use. The strategy |
| * determines whether a connection is persistent or not based on the message’s protocol |
| * version and {@code Connection} header field if present. Connections will not be |
| * re-used and will close if any of these conditions is met |
| * <ul> |
| * <li>the {@code close} connection option is present in the request message</li> |
| * <li>the response message content body is incorrectly or ambiguously delineated</li> |
| * <li>the {@code close} connection option is present in the response message</li> |
| * <li>If the received protocol is {@code HTTP/1.0} (or earlier) and {@code keep-alive} |
| * connection option is not present</li> |
| * </ul> |
| * In the absence of a {@code Connection} header field, the non-standard but commonly used |
| * {@code Proxy-Connection} header field will be used instead. If no connection options are |
| * explicitly given the default policy for the HTTP version is applied. {@code HTTP/1.1} |
| * (or later) connections are re-used by default. {@code HTTP/1.0} (or earlier) connections |
| * are not re-used by default. |
| * |
| * @since 4.0 |
| */ |
| @Contract(threading = ThreadingBehavior.IMMUTABLE) |
| public class DefaultConnectionReuseStrategy implements ConnectionReuseStrategy { |
| |
| public static final DefaultConnectionReuseStrategy INSTANCE = new DefaultConnectionReuseStrategy(); |
| |
| public DefaultConnectionReuseStrategy() { |
| super(); |
| } |
| |
| // see interface ConnectionReuseStrategy |
| @Override |
| public boolean keepAlive( |
| final HttpRequest request, final HttpResponse response, final HttpContext context) { |
| Args.notNull(response, "HTTP response"); |
| |
| if (request != null) { |
| final Iterator<String> ti = new BasicTokenIterator(request.headerIterator(HttpHeaders.CONNECTION)); |
| while (ti.hasNext()) { |
| final String token = ti.next(); |
| if (HeaderElements.CLOSE.equalsIgnoreCase(token)) { |
| return false; |
| } |
| } |
| } |
| |
| // If a HTTP 204 No Content response contains a Content-length with value > 0 or Transfer-Encoding header, |
| // don't reuse the connection. This is to avoid getting out-of-sync if a misbehaved HTTP server |
| // returns content as part of a HTTP 204 response. |
| if (response.getCode() == HttpStatus.SC_NO_CONTENT) { |
| final Header clh = response.getFirstHeader(HttpHeaders.CONTENT_LENGTH); |
| if (clh != null) { |
| try { |
| final long contentLen = Long.parseLong(clh.getValue()); |
| if (contentLen > 0) { |
| return false; |
| } |
| } catch (final NumberFormatException ex) { |
| // fall through |
| } |
| } |
| if (response.containsHeader(HttpHeaders.TRANSFER_ENCODING)) { |
| return false; |
| } |
| } |
| |
| // Check for a self-terminating entity. If the end of the entity will |
| // be indicated by closing the connection, there is no keep-alive. |
| final Header teh = response.getFirstHeader(HttpHeaders.TRANSFER_ENCODING); |
| if (teh != null) { |
| if (!HeaderElements.CHUNKED_ENCODING.equalsIgnoreCase(teh.getValue())) { |
| return false; |
| } |
| } else { |
| final String method = request != null ? request.getMethod() : null; |
| if (MessageSupport.canResponseHaveBody(method, response) |
| && response.countHeaders(HttpHeaders.CONTENT_LENGTH) != 1) { |
| return false; |
| } |
| } |
| |
| // Check for the "Connection" header. If that is absent, check for |
| // the "Proxy-Connection" header. The latter is an unspecified and |
| // broken but unfortunately common extension of HTTP. |
| Iterator<Header> headerIterator = response.headerIterator(HttpHeaders.CONNECTION); |
| if (!headerIterator.hasNext()) { |
| headerIterator = response.headerIterator("Proxy-Connection"); |
| } |
| |
| final ProtocolVersion ver = context.getProtocolVersion(); |
| if (headerIterator.hasNext()) { |
| if (ver.greaterEquals(HttpVersion.HTTP_1_1)) { |
| final Iterator<String> it = new BasicTokenIterator(headerIterator); |
| while (it.hasNext()) { |
| final String token = it.next(); |
| if (HeaderElements.CLOSE.equalsIgnoreCase(token)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| final Iterator<String> it = new BasicTokenIterator(headerIterator); |
| while (it.hasNext()) { |
| final String token = it.next(); |
| if (HeaderElements.KEEP_ALIVE.equalsIgnoreCase(token)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| return ver.greaterEquals(HttpVersion.HTTP_1_1); |
| } |
| |
| } |