mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
synced 2024-09-13 09:24:08 -07:00
174 lines
7.6 KiB
Java
174 lines
7.6 KiB
Java
/*
|
|
* ====================================================================
|
|
* 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 ch.boye.httpclientandroidlib.impl;
|
|
|
|
import ch.boye.httpclientandroidlib.ConnectionReuseStrategy;
|
|
import ch.boye.httpclientandroidlib.HttpConnection;
|
|
import ch.boye.httpclientandroidlib.HeaderIterator;
|
|
import ch.boye.httpclientandroidlib.HttpEntity;
|
|
import ch.boye.httpclientandroidlib.HttpResponse;
|
|
import ch.boye.httpclientandroidlib.HttpVersion;
|
|
import ch.boye.httpclientandroidlib.ParseException;
|
|
import ch.boye.httpclientandroidlib.ProtocolVersion;
|
|
import ch.boye.httpclientandroidlib.protocol.HTTP;
|
|
import ch.boye.httpclientandroidlib.protocol.HttpContext;
|
|
import ch.boye.httpclientandroidlib.protocol.ExecutionContext;
|
|
import ch.boye.httpclientandroidlib.TokenIterator;
|
|
import ch.boye.httpclientandroidlib.message.BasicTokenIterator;
|
|
|
|
/**
|
|
* Default implementation of a strategy deciding about connection re-use.
|
|
* The default implementation first checks some basics, for example
|
|
* whether the connection is still open or whether the end of the
|
|
* request entity can be determined without closing the connection.
|
|
* If these checks pass, the tokens in the <code>Connection</code> header will
|
|
* be examined. In the absence of a <code>Connection</code> header, the
|
|
* non-standard but commonly used <code>Proxy-Connection</code> header takes
|
|
* it's role. A token <code>close</code> indicates that the connection cannot
|
|
* be reused. If there is no such token, a token <code>keep-alive</code>
|
|
* indicates that the connection should be re-used. If neither token is found,
|
|
* or if there are no <code>Connection</code> headers, the default policy for
|
|
* the HTTP version is applied. Since <code>HTTP/1.1</code>, connections are
|
|
* re-used by default. Up until <code>HTTP/1.0</code>, connections are not
|
|
* re-used by default.
|
|
*
|
|
* @since 4.0
|
|
*/
|
|
public class DefaultConnectionReuseStrategy implements ConnectionReuseStrategy {
|
|
|
|
public DefaultConnectionReuseStrategy() {
|
|
super();
|
|
}
|
|
|
|
// see interface ConnectionReuseStrategy
|
|
public boolean keepAlive(final HttpResponse response,
|
|
final HttpContext context) {
|
|
if (response == null) {
|
|
throw new IllegalArgumentException
|
|
("HTTP response may not be null.");
|
|
}
|
|
if (context == null) {
|
|
throw new IllegalArgumentException
|
|
("HTTP context may not be null.");
|
|
}
|
|
|
|
HttpConnection conn = (HttpConnection)
|
|
context.getAttribute(ExecutionContext.HTTP_CONNECTION);
|
|
|
|
if (conn != null && !conn.isOpen())
|
|
return false;
|
|
// do NOT check for stale connection, that is an expensive operation
|
|
|
|
// Check for a self-terminating entity. If the end of the entity will
|
|
// be indicated by closing the connection, there is no keep-alive.
|
|
HttpEntity entity = response.getEntity();
|
|
ProtocolVersion ver = response.getStatusLine().getProtocolVersion();
|
|
if (entity != null) {
|
|
if (entity.getContentLength() < 0) {
|
|
if (!entity.isChunked() ||
|
|
ver.lessEquals(HttpVersion.HTTP_1_0)) {
|
|
// if the content length is not known and is not chunk
|
|
// encoded, the connection cannot be reused
|
|
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.
|
|
HeaderIterator hit = response.headerIterator(HTTP.CONN_DIRECTIVE);
|
|
if (!hit.hasNext())
|
|
hit = response.headerIterator("Proxy-Connection");
|
|
|
|
// Experimental usage of the "Connection" header in HTTP/1.0 is
|
|
// documented in RFC 2068, section 19.7.1. A token "keep-alive" is
|
|
// used to indicate that the connection should be persistent.
|
|
// Note that the final specification of HTTP/1.1 in RFC 2616 does not
|
|
// include this information. Neither is the "Connection" header
|
|
// mentioned in RFC 1945, which informally describes HTTP/1.0.
|
|
//
|
|
// RFC 2616 specifies "close" as the only connection token with a
|
|
// specific meaning: it disables persistent connections.
|
|
//
|
|
// The "Proxy-Connection" header is not formally specified anywhere,
|
|
// but is commonly used to carry one token, "close" or "keep-alive".
|
|
// The "Connection" header, on the other hand, is defined as a
|
|
// sequence of tokens, where each token is a header name, and the
|
|
// token "close" has the above-mentioned additional meaning.
|
|
//
|
|
// To get through this mess, we treat the "Proxy-Connection" header
|
|
// in exactly the same way as the "Connection" header, but only if
|
|
// the latter is missing. We scan the sequence of tokens for both
|
|
// "close" and "keep-alive". As "close" is specified by RFC 2068,
|
|
// it takes precedence and indicates a non-persistent connection.
|
|
// If there is no "close" but a "keep-alive", we take the hint.
|
|
|
|
if (hit.hasNext()) {
|
|
try {
|
|
TokenIterator ti = createTokenIterator(hit);
|
|
boolean keepalive = false;
|
|
while (ti.hasNext()) {
|
|
final String token = ti.nextToken();
|
|
if (HTTP.CONN_CLOSE.equalsIgnoreCase(token)) {
|
|
return false;
|
|
} else if (HTTP.CONN_KEEP_ALIVE.equalsIgnoreCase(token)) {
|
|
// continue the loop, there may be a "close" afterwards
|
|
keepalive = true;
|
|
}
|
|
}
|
|
if (keepalive)
|
|
return true;
|
|
// neither "close" nor "keep-alive", use default policy
|
|
|
|
} catch (ParseException px) {
|
|
// invalid connection header means no persistent connection
|
|
// we don't have logging in HttpCore, so the exception is lost
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// default since HTTP/1.1 is persistent, before it was non-persistent
|
|
return !ver.lessEquals(HttpVersion.HTTP_1_0);
|
|
}
|
|
|
|
|
|
/**
|
|
* Creates a token iterator from a header iterator.
|
|
* This method can be overridden to replace the implementation of
|
|
* the token iterator.
|
|
*
|
|
* @param hit the header iterator
|
|
*
|
|
* @return the token iterator
|
|
*/
|
|
protected TokenIterator createTokenIterator(HeaderIterator hit) {
|
|
return new BasicTokenIterator(hit);
|
|
}
|
|
}
|