001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.http;
014
015import org.apache.juneau.http.annotation.*;
016
017/**
018 * Represents a parsed <l>Content-Range</l> HTTP response header.
019 *
020 * <p>
021 * Where in a full body message this partial message belongs.
022 *
023 * <h5 class='figure'>Example</h5>
024 * <p class='bcode w800'>
025 *    Content-Range: bytes 21010-47021/47022
026 * </p>
027 *
028 * <h5 class='topic'>RFC2616 Specification</h5>
029 *
030 * The Content-Range entity-header is sent with a partial entity-body to specify where in the full entity-body the
031 * partial body should be applied.
032 * Range units are defined in section 3.12.
033 * <p class='bcode w800'>
034 *    Content-Range = "Content-Range" ":" content-range-spec
035 *    content-range-spec      = byte-content-range-spec
036 *    byte-content-range-spec = bytes-unit SP
037 *                              byte-range-resp-spec "/"
038 *                              ( instance-length | "*" )
039 *    byte-range-resp-spec = (first-byte-pos "-" last-byte-pos)
040 *                                   | "*"
041 *    instance-length           = 1*DIGIT
042 * </p>
043 *
044 * <p>
045 * The header SHOULD indicate the total length of the full entity-body, unless this length is unknown or difficult to
046 * determine.
047 * The asterisk "*" character means that the instance-length is unknown at the time when the response was generated.
048 *
049 * <p>
050 * Unlike byte-ranges-specifier values (see section 14.35.1), a byte- range-resp-spec MUST only specify one range, and
051 * MUST contain absolute byte positions for both the first and last byte of the range.
052 *
053 * <p>
054 * A byte-content-range-spec with a byte-range-resp-spec whose last- byte-pos value is less than its first-byte-pos
055 * value, or whose instance-length value is less than or equal to its last-byte-pos value, is invalid.
056 * The recipient of an invalid byte-content-range- spec MUST ignore it and any content transferred along with it.
057 *
058 * <p>
059 * A server sending a response with status code 416 (Requested range not satisfiable) SHOULD include a Content-Range
060 * field with a byte-range- resp-spec of "*".
061 * The instance-length specifies the current length of the selected resource.
062 * A response with status code 206 (Partial Content) MUST NOT include a Content-Range field with a byte-range-resp-spec
063 * of "*".
064 *
065 * <p>
066 * Examples of byte-content-range-spec values, assuming that the entity contains a total of 1234 bytes:
067 * <p class='bcode w800'>
068 *    The first 500 bytes:
069 *     bytes 0-499/1234
070 *    The second 500 bytes:
071 *     bytes 500-999/1234
072 *    All except for the first 500 bytes:
073 *     bytes 500-1233/1234
074 *    The last 500 bytes:
075 *     bytes 734-1233/1234
076 * </p>
077 *
078 * <p>
079 * When an HTTP message includes the content of a single range (for example, a response to a request for a single range,
080 * or to a request for a set of ranges that overlap without any holes), this content is transmitted with a Content-Range
081 * header, and a Content-Length header showing the number of bytes actually transferred.
082 * For example:
083 * <p class='bcode w800'>
084 *    HTTP/1.1 206 Partial content
085 *    Date: Wed, 15 Nov 1995 06:25:24 GMT
086 *    Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
087 *    Content-Range: bytes 21010-47021/47022
088 *    Content-Length: 26012
089 *    Content-Type: image/gif
090 * </p>
091 *
092 * <p>
093 * When an HTTP message includes the content of multiple ranges (for example, a response to a request for multiple
094 * non-overlapping ranges), these are transmitted as a multipart message.
095 * The multipart media type used for this purpose is "multipart/byteranges" as defined in appendix 19.2.
096 * See appendix 19.6.3 for a compatibility issue.
097 *
098 * <p>
099 * A response to a request for a single range MUST NOT be sent using the multipart/byteranges media type.
100 * A response to a request for multiple ranges, whose result is a single range, MAY be sent as a multipart/byteranges
101 * media type with one part.
102 * A client that cannot decode a multipart/byteranges message MUST NOT ask for multiple byte-ranges in a single request.
103 *
104 * <p>
105 * When a client requests multiple byte-ranges in one request, the server SHOULD return them in the order that they
106 * appeared in the request.
107 *
108 * <p>
109 * If the server ignores a byte-range-spec because it is syntactically invalid, the server SHOULD treat the request as
110 * if the invalid Range header field did not exist.
111 * (Normally, this means return a 200 response containing the full entity).
112 *
113 * <p>
114 * If the server receives a request (other than one including an If- Range request-header field) with an unsatisfiable
115 * Range request- header field
116 * (that is, all of whose byte-range-spec values have a first-byte-pos value greater than the current length of the
117 * selected resource),
118 * it SHOULD return a response code of 416 (Requested range not satisfiable) (section 10.4.17).
119 *
120 * <p>
121 * Note: clients cannot depend on servers to send a 416 (Requested range not satisfiable) response instead of a 200 (OK)
122 * response for
123 * an unsatisfiable Range request-header, since not all servers implement this request-header.
124 *
125 * <h5 class='section'>See Also:</h5>
126 * <ul class='doctree'>
127 *    <li class='extlink'>{@doc RFC2616}
128 * </ul>
129 */
130@Header("Content-Range")
131public final class ContentRange extends HeaderString {
132
133   /**
134    * Returns a parsed <code>Content-Range</code> header.
135    *
136    * @param value The <code>Content-Range</code> header string.
137    * @return The parsed <code>Content-Range</code> header, or <jk>null</jk> if the string was null.
138    */
139   public static ContentRange forString(String value) {
140      if (value == null)
141         return null;
142      return new ContentRange(value);
143   }
144
145   private ContentRange(String value) {
146      super(value);
147   }
148}