mobile/android/thirdparty/ch/boye/httpclientandroidlib/impl/DefaultConnectionReuseStrategy.java@fc2d59ddac77 (annotated)
mobile/android/thirdparty/ch/boye/httpclientandroidlib/impl/DefaultConnectionReuseStrategy.java
Wed, 31 Dec 2014 07:22:50 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 07:22:50 +0100
- branch
- TOR_BUG_3246
- changeset 4
- fc2d59ddac77
- permissions
- -rw-r--r--
Correct previous dual key logic pending first delivery installment.
| michael@0 | 1 | /* |
| michael@0 | 2 | * ==================================================================== |
| michael@0 | 3 | * Licensed to the Apache Software Foundation (ASF) under one |
| michael@0 | 4 | * or more contributor license agreements. See the NOTICE file |
| michael@0 | 5 | * distributed with this work for additional information |
| michael@0 | 6 | * regarding copyright ownership. The ASF licenses this file |
| michael@0 | 7 | * to you under the Apache License, Version 2.0 (the |
| michael@0 | 8 | * "License"); you may not use this file except in compliance |
| michael@0 | 9 | * with the License. You may obtain a copy of the License at |
| michael@0 | 10 | * |
| michael@0 | 11 | * http://www.apache.org/licenses/LICENSE-2.0 |
| michael@0 | 12 | * |
| michael@0 | 13 | * Unless required by applicable law or agreed to in writing, |
| michael@0 | 14 | * software distributed under the License is distributed on an |
| michael@0 | 15 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| michael@0 | 16 | * KIND, either express or implied. See the License for the |
| michael@0 | 17 | * specific language governing permissions and limitations |
| michael@0 | 18 | * under the License. |
| michael@0 | 19 | * ==================================================================== |
| michael@0 | 20 | * |
| michael@0 | 21 | * This software consists of voluntary contributions made by many |
| michael@0 | 22 | * individuals on behalf of the Apache Software Foundation. For more |
| michael@0 | 23 | * information on the Apache Software Foundation, please see |
| michael@0 | 24 | * <http://www.apache.org/>. |
| michael@0 | 25 | * |
| michael@0 | 26 | */ |
| michael@0 | 27 | |
| michael@0 | 28 | package ch.boye.httpclientandroidlib.impl; |
| michael@0 | 29 | |
| michael@0 | 30 | import ch.boye.httpclientandroidlib.ConnectionReuseStrategy; |
| michael@0 | 31 | import ch.boye.httpclientandroidlib.HttpConnection; |
| michael@0 | 32 | import ch.boye.httpclientandroidlib.HeaderIterator; |
| michael@0 | 33 | import ch.boye.httpclientandroidlib.HttpEntity; |
| michael@0 | 34 | import ch.boye.httpclientandroidlib.HttpResponse; |
| michael@0 | 35 | import ch.boye.httpclientandroidlib.HttpVersion; |
| michael@0 | 36 | import ch.boye.httpclientandroidlib.ParseException; |
| michael@0 | 37 | import ch.boye.httpclientandroidlib.ProtocolVersion; |
| michael@0 | 38 | import ch.boye.httpclientandroidlib.protocol.HTTP; |
| michael@0 | 39 | import ch.boye.httpclientandroidlib.protocol.HttpContext; |
| michael@0 | 40 | import ch.boye.httpclientandroidlib.protocol.ExecutionContext; |
| michael@0 | 41 | import ch.boye.httpclientandroidlib.TokenIterator; |
| michael@0 | 42 | import ch.boye.httpclientandroidlib.message.BasicTokenIterator; |
| michael@0 | 43 | |
| michael@0 | 44 | /** |
| michael@0 | 45 | * Default implementation of a strategy deciding about connection re-use. |
| michael@0 | 46 | * The default implementation first checks some basics, for example |
| michael@0 | 47 | * whether the connection is still open or whether the end of the |
| michael@0 | 48 | * request entity can be determined without closing the connection. |
| michael@0 | 49 | * If these checks pass, the tokens in the <code>Connection</code> header will |
| michael@0 | 50 | * be examined. In the absence of a <code>Connection</code> header, the |
| michael@0 | 51 | * non-standard but commonly used <code>Proxy-Connection</code> header takes |
| michael@0 | 52 | * it's role. A token <code>close</code> indicates that the connection cannot |
| michael@0 | 53 | * be reused. If there is no such token, a token <code>keep-alive</code> |
| michael@0 | 54 | * indicates that the connection should be re-used. If neither token is found, |
| michael@0 | 55 | * or if there are no <code>Connection</code> headers, the default policy for |
| michael@0 | 56 | * the HTTP version is applied. Since <code>HTTP/1.1</code>, connections are |
| michael@0 | 57 | * re-used by default. Up until <code>HTTP/1.0</code>, connections are not |
| michael@0 | 58 | * re-used by default. |
| michael@0 | 59 | * |
| michael@0 | 60 | * @since 4.0 |
| michael@0 | 61 | */ |
| michael@0 | 62 | public class DefaultConnectionReuseStrategy implements ConnectionReuseStrategy { |
| michael@0 | 63 | |
| michael@0 | 64 | public DefaultConnectionReuseStrategy() { |
| michael@0 | 65 | super(); |
| michael@0 | 66 | } |
| michael@0 | 67 | |
| michael@0 | 68 | // see interface ConnectionReuseStrategy |
| michael@0 | 69 | public boolean keepAlive(final HttpResponse response, |
| michael@0 | 70 | final HttpContext context) { |
| michael@0 | 71 | if (response == null) { |
| michael@0 | 72 | throw new IllegalArgumentException |
| michael@0 | 73 | ("HTTP response may not be null."); |
| michael@0 | 74 | } |
| michael@0 | 75 | if (context == null) { |
| michael@0 | 76 | throw new IllegalArgumentException |
| michael@0 | 77 | ("HTTP context may not be null."); |
| michael@0 | 78 | } |
| michael@0 | 79 | |
| michael@0 | 80 | HttpConnection conn = (HttpConnection) |
| michael@0 | 81 | context.getAttribute(ExecutionContext.HTTP_CONNECTION); |
| michael@0 | 82 | |
| michael@0 | 83 | if (conn != null && !conn.isOpen()) |
| michael@0 | 84 | return false; |
| michael@0 | 85 | // do NOT check for stale connection, that is an expensive operation |
| michael@0 | 86 | |
| michael@0 | 87 | // Check for a self-terminating entity. If the end of the entity will |
| michael@0 | 88 | // be indicated by closing the connection, there is no keep-alive. |
| michael@0 | 89 | HttpEntity entity = response.getEntity(); |
| michael@0 | 90 | ProtocolVersion ver = response.getStatusLine().getProtocolVersion(); |
| michael@0 | 91 | if (entity != null) { |
| michael@0 | 92 | if (entity.getContentLength() < 0) { |
| michael@0 | 93 | if (!entity.isChunked() || |
| michael@0 | 94 | ver.lessEquals(HttpVersion.HTTP_1_0)) { |
| michael@0 | 95 | // if the content length is not known and is not chunk |
| michael@0 | 96 | // encoded, the connection cannot be reused |
| michael@0 | 97 | return false; |
| michael@0 | 98 | } |
| michael@0 | 99 | } |
| michael@0 | 100 | } |
| michael@0 | 101 | |
| michael@0 | 102 | // Check for the "Connection" header. If that is absent, check for |
| michael@0 | 103 | // the "Proxy-Connection" header. The latter is an unspecified and |
| michael@0 | 104 | // broken but unfortunately common extension of HTTP. |
| michael@0 | 105 | HeaderIterator hit = response.headerIterator(HTTP.CONN_DIRECTIVE); |
| michael@0 | 106 | if (!hit.hasNext()) |
| michael@0 | 107 | hit = response.headerIterator("Proxy-Connection"); |
| michael@0 | 108 | |
| michael@0 | 109 | // Experimental usage of the "Connection" header in HTTP/1.0 is |
| michael@0 | 110 | // documented in RFC 2068, section 19.7.1. A token "keep-alive" is |
| michael@0 | 111 | // used to indicate that the connection should be persistent. |
| michael@0 | 112 | // Note that the final specification of HTTP/1.1 in RFC 2616 does not |
| michael@0 | 113 | // include this information. Neither is the "Connection" header |
| michael@0 | 114 | // mentioned in RFC 1945, which informally describes HTTP/1.0. |
| michael@0 | 115 | // |
| michael@0 | 116 | // RFC 2616 specifies "close" as the only connection token with a |
| michael@0 | 117 | // specific meaning: it disables persistent connections. |
| michael@0 | 118 | // |
| michael@0 | 119 | // The "Proxy-Connection" header is not formally specified anywhere, |
| michael@0 | 120 | // but is commonly used to carry one token, "close" or "keep-alive". |
| michael@0 | 121 | // The "Connection" header, on the other hand, is defined as a |
| michael@0 | 122 | // sequence of tokens, where each token is a header name, and the |
| michael@0 | 123 | // token "close" has the above-mentioned additional meaning. |
| michael@0 | 124 | // |
| michael@0 | 125 | // To get through this mess, we treat the "Proxy-Connection" header |
| michael@0 | 126 | // in exactly the same way as the "Connection" header, but only if |
| michael@0 | 127 | // the latter is missing. We scan the sequence of tokens for both |
| michael@0 | 128 | // "close" and "keep-alive". As "close" is specified by RFC 2068, |
| michael@0 | 129 | // it takes precedence and indicates a non-persistent connection. |
| michael@0 | 130 | // If there is no "close" but a "keep-alive", we take the hint. |
| michael@0 | 131 | |
| michael@0 | 132 | if (hit.hasNext()) { |
| michael@0 | 133 | try { |
| michael@0 | 134 | TokenIterator ti = createTokenIterator(hit); |
| michael@0 | 135 | boolean keepalive = false; |
| michael@0 | 136 | while (ti.hasNext()) { |
| michael@0 | 137 | final String token = ti.nextToken(); |
| michael@0 | 138 | if (HTTP.CONN_CLOSE.equalsIgnoreCase(token)) { |
| michael@0 | 139 | return false; |
| michael@0 | 140 | } else if (HTTP.CONN_KEEP_ALIVE.equalsIgnoreCase(token)) { |
| michael@0 | 141 | // continue the loop, there may be a "close" afterwards |
| michael@0 | 142 | keepalive = true; |
| michael@0 | 143 | } |
| michael@0 | 144 | } |
| michael@0 | 145 | if (keepalive) |
| michael@0 | 146 | return true; |
| michael@0 | 147 | // neither "close" nor "keep-alive", use default policy |
| michael@0 | 148 | |
| michael@0 | 149 | } catch (ParseException px) { |
| michael@0 | 150 | // invalid connection header means no persistent connection |
| michael@0 | 151 | // we don't have logging in HttpCore, so the exception is lost |
| michael@0 | 152 | return false; |
| michael@0 | 153 | } |
| michael@0 | 154 | } |
| michael@0 | 155 | |
| michael@0 | 156 | // default since HTTP/1.1 is persistent, before it was non-persistent |
| michael@0 | 157 | return !ver.lessEquals(HttpVersion.HTTP_1_0); |
| michael@0 | 158 | } |
| michael@0 | 159 | |
| michael@0 | 160 | |
| michael@0 | 161 | /** |
| michael@0 | 162 | * Creates a token iterator from a header iterator. |
| michael@0 | 163 | * This method can be overridden to replace the implementation of |
| michael@0 | 164 | * the token iterator. |
| michael@0 | 165 | * |
| michael@0 | 166 | * @param hit the header iterator |
| michael@0 | 167 | * |
| michael@0 | 168 | * @return the token iterator |
| michael@0 | 169 | */ |
| michael@0 | 170 | protected TokenIterator createTokenIterator(HeaderIterator hit) { |
| michael@0 | 171 | return new BasicTokenIterator(hit); |
| michael@0 | 172 | } |
| michael@0 | 173 | } |
