| // *************************************************************************************************************************** |
| // * 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. * |
| // *************************************************************************************************************************** |
| package org.apache.juneau.http; |
| |
| import org.apache.juneau.http.annotation.*; |
| |
| /** |
| * Represents a parsed <l>Via</l> HTTP response header. |
| * |
| * <p> |
| * Informs the client of proxies through which the response was sent. |
| * |
| * <h5 class='figure'>Example</h5> |
| * <p class='bcode w800'> |
| * Via: 1.0 fred, 1.1 example.com (Apache/1.1) |
| * </p> |
| * |
| * <p> |
| * Informs the client of proxies through which the response was sent. |
| * |
| * <p> |
| * <h5 class='figure'>Example</h5> |
| * <p class='bcode w800'> |
| * Via: 1.0 fred, 1.1 example.com (Apache/1.1) |
| * </p> |
| * |
| * <p> |
| * <h5 class='topic'>RFC2616 Specification</h5> |
| * |
| * The Via general-header field MUST be used by gateways and proxies to indicate the intermediate protocols and |
| * recipients between the user agent and the server on requests, and between the origin server and the client on |
| * responses. |
| * It is analogous to the "Received" field of RFC 822 and is intended to be used for tracking message forwards, |
| * avoiding request loops, and identifying the protocol capabilities of all senders along the request/response chain. |
| * |
| * <p class='bcode w800'> |
| * Via = "Via" ":" 1#( received-protocol received-by [ comment ] ) |
| * received-protocol = [ protocol-name "/" ] protocol-version |
| * protocol-name = token |
| * protocol-version = token |
| * received-by = ( host [ ":" port ] ) | pseudonym |
| * pseudonym = token |
| * </p> |
| * |
| * <p> |
| * The received-protocol indicates the protocol version of the message received by the server or client along each |
| * segment of the request/response chain. |
| * The received-protocol version is appended to the Via field value when the message is forwarded so that information |
| * about the protocol capabilities of upstream applications remains visible to all recipients. |
| * |
| * <p> |
| * The protocol-name is optional if and only if it would be "HTTP". |
| * The received-by field is normally the host and optional port number of a recipient server or client that subsequently |
| * forwarded the message. |
| * However, if the real host is considered to be sensitive information, it MAY be replaced by a pseudonym. |
| * If the port is not given, it MAY be assumed to be the default port of the received-protocol. |
| * |
| * <p> |
| * Multiple Via field values represents each proxy or gateway that has forwarded the message. |
| * Each recipient MUST append its information such that the end result is ordered according to the sequence of |
| * forwarding applications. |
| * |
| * <p> |
| * Comments MAY be used in the Via header field to identify the software of the recipient proxy or gateway, analogous |
| * to the User-Agent and Server header fields. |
| * However, all comments in the Via field are optional and MAY be removed by any recipient prior to forwarding the |
| * message. |
| * |
| * <p> |
| * For example, a request message could be sent from an HTTP/1.0 user agent to an internal proxy code-named "fred", |
| * which uses HTTP/1.1 to forward the request to a public proxy at nowhere.com, which completes the request by |
| * forwarding it to the origin server at www.ics.uci.edu. |
| * The request received by www.ics.uci.edu would then have the following Via header field: |
| * <p class='bcode w800'> |
| * Via: 1.0 fred, 1.1 nowhere.com (Apache/1.1) |
| * </p> |
| * |
| * <p> |
| * Proxies and gateways used as a portal through a network firewall SHOULD NOT, by default, forward the names and ports |
| * of hosts within the firewall region. |
| * This information SHOULD only be propagated if explicitly enabled. |
| * If not enabled, the received-by host of any host behind the firewall SHOULD be replaced by an appropriate pseudonym |
| * for that host. |
| * |
| * <p> |
| * For organizations that have strong privacy requirements for hiding internal structures, a proxy MAY combine an |
| * ordered subsequence of Via header field entries with identical received-protocol values into a single such entry. |
| * For example... |
| * <p class='bcode w800'> |
| * Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy |
| * </p> |
| * |
| * <p> |
| * ...could be collapsed to... |
| * <p class='bcode w800'> |
| * Via: 1.0 ricky, 1.1 mertz, 1.0 lucy |
| * </p> |
| * |
| * <p> |
| * Applications SHOULD NOT combine multiple entries unless they are all under the same organizational control and the |
| * hosts have already been replaced by pseudonyms. |
| * Applications MUST NOT combine entries which have different received-protocol values. |
| * |
| * <ul class='seealso'> |
| * <li class='extlink'>{@doc RFC2616} |
| * </ul> |
| */ |
| @Header("Via") |
| public final class Via extends HeaderStringArray { |
| |
| /** |
| * Constructor. |
| * |
| * @param value The value for this header. |
| */ |
| public Via(String[] value) { |
| super(value); |
| } |
| |
| /** |
| * Returns a parsed <c>Via</c> header. |
| * |
| * @param value The <c>Via</c> header string. |
| * @return The parsed <c>Via</c> header, or <jk>null</jk> if the string was null. |
| */ |
| public static Via forString(String value) { |
| if (value == null) |
| return null; |
| return new Via(value); |
| } |
| |
| private Via(String value) { |
| super(value); |
| } |
| } |
