| // *************************************************************************************************************************** |
| // * 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>Range</l> HTTP request header. |
| * |
| * <p> |
| * Request only part of an entity. Bytes are numbered from 0. |
| * |
| * <h5 class='figure'>Example</h5> |
| * <p class='bcode w800'> |
| * Range: bytes=500-999 |
| * </p> |
| * |
| * <h5 class='topic'>RFC2616 Specification</h5> |
| * |
| * Since all HTTP entities are represented in HTTP messages as sequences of bytes, the concept of a byte range is |
| * meaningful for any HTTP entity. |
| * (However, not all clients and servers need to support byte- range operations.) |
| * |
| * <p> |
| * Byte range specifications in HTTP apply to the sequence of bytes in the entity-body (not necessarily the same as the |
| * message-body). |
| * |
| * <p> |
| * A byte range operation MAY specify a single range of bytes, or a set of ranges within a single entity. |
| * <p class='bcode w800'> |
| * ranges-specifier = byte-ranges-specifier |
| * byte-ranges-specifier = bytes-unit "=" byte-range-set |
| * byte-range-set = 1#( byte-range-spec | suffix-byte-range-spec ) |
| * byte-range-spec = first-byte-pos "-" [last-byte-pos] |
| * first-byte-pos = 1*DIGIT |
| * last-byte-pos = 1*DIGIT |
| * </p> |
| * |
| * <p> |
| * The first-byte-pos value in a byte-range-spec gives the byte-offset of the first byte in a range. |
| * The last-byte-pos value gives the byte-offset of the last byte in the range; that is, the byte positions specified |
| * are inclusive. |
| * Byte offsets start at zero. |
| * |
| * <p> |
| * If the last-byte-pos value is present, it MUST be greater than or equal to the first-byte-pos in that |
| * byte-range-spec, or the byte- range-spec is syntactically invalid. |
| * The recipient of a byte-range- set that includes one or more syntactically invalid byte-range-spec values MUST |
| * ignore the header field that includes that byte-range-set. |
| * |
| * <p> |
| * If the last-byte-pos value is absent, or if the value is greater than or equal to the current length of the |
| * entity-body, last-byte-pos is taken to be equal to one less than the current length of the entity-body in bytes. |
| * |
| * <p> |
| * By its choice of last-byte-pos, a client can limit the number of bytes retrieved without knowing the size of the |
| * entity. |
| * <p class='bcode w800'> |
| * suffix-byte-range-spec = "-" suffix-length |
| * suffix-length = 1*DIGIT |
| * </p> |
| * |
| * <p> |
| * A suffix-byte-range-spec is used to specify the suffix of the entity-body, of a length given by the suffix-length |
| * value. |
| * (That is, this form specifies the last N bytes of an entity-body.) |
| * If the entity is shorter than the specified suffix-length, the entire entity-body is used. |
| * |
| * <p> |
| * If a syntactically valid byte-range-set includes at least one byte- range-spec whose first-byte-pos is less than the |
| * current length of the entity-body, or at least one suffix-byte-range-spec with a non-zero suffix-length, then the |
| * byte-range-set is satisfiable. |
| * Otherwise, the byte-range-set is unsatisfiable. |
| * If the byte-range-set is unsatisfiable, the server SHOULD return a response with a status of 416 (Requested range |
| * not satisfiable). |
| * Otherwise, the server SHOULD return a response with a status of 206 (Partial Content) containing the satisfiable |
| * ranges of the entity-body. |
| * |
| * <p> |
| * Examples of byte-ranges-specifier values (assuming an entity-body of length 10000): |
| * <p class='bcode w800'> |
| * - The first 500 bytes (byte offsets 0-499, inclusive): bytes=0-499 |
| * - The second 500 bytes (byte offsets 500-999, inclusive): bytes=500-999 |
| * - The final 500 bytes (byte offsets 9500-9999, inclusive): bytes=-500 |
| * - Or bytes=9500- |
| * - The first and last bytes only (bytes 0 and 9999): bytes=0-0,-1 |
| * - Several legal but not canonical specifications of the second 500 bytes (byte offsets 500-999, inclusive): |
| * bytes=500-600,601-999 |
| * bytes=500-700,601-999 |
| * </p> |
| * |
| * <p> |
| * HTTP retrieval requests using conditional or unconditional GET methods MAY request one or more sub-ranges of the |
| * entity, instead of the entire entity, using the Range request header, which applies to the entity returned as the |
| * result of the request: |
| * |
| * <p class='bcode w800'> |
| * Range = "Range" ":" ranges-specifier |
| * </p> |
| * |
| * <p> |
| * A server MAY ignore the Range header. |
| * However, HTTP/1.1 origin servers and intermediate caches ought to support byte ranges when possible, since Range |
| * supports efficient recovery from partially failed transfers, and supports efficient partial retrieval of large |
| * entities. |
| * |
| * <p> |
| * If the server supports the Range header and the specified range or ranges are appropriate for the entity: |
| * <ul> |
| * <li>The presence of a Range header in an unconditional GET modifies what is returned if the GET is otherwise |
| * successful. |
| * In other words, the response carries a status code of 206 (Partial Content) instead of 200 (OK). |
| * <li>The presence of a Range header in a conditional GET (a request using one or both of If-Modified-Since and |
| * If-None-Match, or one or both of If-Unmodified-Since and If-Match) modifies what is returned if the GET is |
| * otherwise successful and the condition is true. It does not affect the 304 (Not Modified) response returned if |
| * the conditional is false. |
| * </ul> |
| * |
| * <p> |
| * In some cases, it might be more appropriate to use the If-Range header (see section 14.27) in addition to the Range |
| * header. |
| * |
| * <p> |
| * If a proxy that supports ranges receives a Range request, forwards the request to an inbound server, and receives an |
| * entire entity in reply, it SHOULD only return the requested range to its client. |
| * It SHOULD store the entire received response in its cache if that is consistent with its cache allocation policies. |
| * |
| * <ul class='seealso'> |
| * <li class='extlink'>{@doc RFC2616} |
| * </ul> |
| */ |
| @Header("Range") |
| public final class Range extends HeaderString { |
| |
| /** |
| * Returns a parsed <c>Range</c> header. |
| * |
| * @param value The <c>Range</c> header string. |
| * @return The parsed <c>Range</c> header, or <jk>null</jk> if the string was null. |
| */ |
| public static Range forString(String value) { |
| if (value == null) |
| return null; |
| return new Range(value); |
| } |
| |
| private Range(String value) { |
| super(value); |
| } |
| } |
