| // *************************************************************************************************************************** |
| // * 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 static org.apache.juneau.http.Constants.*; |
| |
| import org.apache.juneau.http.annotation.*; |
| import org.apache.juneau.internal.*; |
| |
| /** |
| * Represents a parsed <l>Accept-Encoding</l> HTTP request header. |
| * |
| * <p> |
| * List of acceptable encodings. |
| * |
| * <h5 class='figure'>Example</h5> |
| * <p class='bcode w800'> |
| * Accept-Encoding: gzip, deflate |
| * </p> |
| * |
| * <h5 class='topic'>RFC2616 Specification</h5> |
| * |
| * The Accept-Encoding request-header field is similar to Accept, but restricts the content-codings (section 3.5) that |
| * are acceptable in the response. |
| * |
| * <p class='bcode w800'> |
| * Accept-Encoding = "Accept-Encoding" ":" |
| * 1#( codings [ ";" "q" "=" qvalue ] ) |
| * codings = ( content-coding | "*" ) |
| * </p> |
| * |
| * <p> |
| * Examples of its use are: |
| * <p class='bcode w800'> |
| * Accept-Encoding: compress, gzip |
| * Accept-Encoding: |
| * Accept-Encoding: * |
| * Accept-Encoding: compress;q=0.5, gzip;q=1.0 |
| * Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0 |
| * </p> |
| * |
| * <p> |
| * A server tests whether a content-coding is acceptable, according to an Accept-Encoding field, using these rules: |
| * <ol> |
| * <li>If the content-coding is one of the content-codings listed in the Accept-Encoding field, then it is |
| * acceptable, unless it is accompanied by a qvalue of 0. |
| * (As defined in section 3.9, a qvalue of 0 means "not acceptable.") |
| * <li>The special "*" symbol in an Accept-Encoding field matches any available content-coding not explicitly listed |
| * in the header field. |
| * <li>If multiple content-codings are acceptable, then the acceptable content-coding with the highest non-zero |
| * qvalue is preferred. |
| * <li>The "identity" content-coding is always acceptable, unless specifically refused because the Accept-Encoding |
| * field includes "identity;q=0", or because the field includes "*;q=0" and does not explicitly include the |
| * "identity" content-coding. |
| * If the Accept-Encoding field-value is empty, then only the "identity" encoding is acceptable. |
| * </ol> |
| * |
| * <p> |
| * If an Accept-Encoding field is present in a request, and if the server cannot send a response which is acceptable |
| * according to the Accept-Encoding header, then the server SHOULD send an error response with the 406 (Not Acceptable) |
| * status code. |
| * |
| * <p> |
| * If no Accept-Encoding field is present in a request, the server MAY assume that the client will accept any content |
| * coding. |
| * In this case, if "identity" is one of the available content-codings, then the server SHOULD use the "identity" |
| * content-coding, unless it has additional information that a different content-coding is meaningful to the client. |
| * |
| * <p> |
| * Note: If the request does not include an Accept-Encoding field, and if the "identity" content-coding is unavailable, |
| * then content-codings commonly understood by HTTP/1.0 clients (i.e.,"gzip" and "compress") are preferred; some older |
| * clients improperly display messages sent with other content-codings. |
| * The server might also make this decision based on information about the particular user-agent or client. |
| * |
| * <p> |
| * Note: Most HTTP/1.0 applications do not recognize or obey qvalues associated with content-codings. |
| * This means that qvalues will not work and are not permitted with x-gzip or x-compress. |
| * |
| * <ul class='seealso'> |
| * <li class='extlink'>{@doc RFC2616} |
| * </ul> |
| */ |
| @Header("Accept-Encoding") |
| public final class AcceptEncoding extends HeaderRangeArray { |
| |
| private static final Cache<String,AcceptEncoding> cache = new Cache<>(NOCACHE, CACHE_MAX_SIZE); |
| |
| /** |
| * Returns a parsed <c>Accept-Encoding</c> header. |
| * |
| * @param value The <c>Accept-Encoding</c> header string. |
| * @return The parsed <c>Accept-Encoding</c> header, or <jk>null</jk> if the string was null. |
| */ |
| public static AcceptEncoding forString(String value) { |
| if (value == null) |
| return null; |
| AcceptEncoding a = cache.get(value); |
| if (a == null) |
| a = cache.put(value, new AcceptEncoding(value)); |
| return a; |
| } |
| |
| private AcceptEncoding(String value) { |
| super(value); |
| } |
| } |