1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28
29 package org.apache.hc.client5.http.protocol;
30
31
32 import java.io.IOException;
33 import java.time.Instant;
34
35 import org.apache.hc.client5.http.utils.DateUtils;
36 import org.apache.hc.core5.annotation.Contract;
37 import org.apache.hc.core5.annotation.ThreadingBehavior;
38 import org.apache.hc.core5.http.EntityDetails;
39 import org.apache.hc.core5.http.Header;
40 import org.apache.hc.core5.http.HttpException;
41 import org.apache.hc.core5.http.HttpHeaders;
42 import org.apache.hc.core5.http.HttpRequest;
43 import org.apache.hc.core5.http.HttpRequestInterceptor;
44 import org.apache.hc.core5.http.ProtocolException;
45 import org.apache.hc.core5.http.protocol.HttpContext;
46 import org.apache.hc.core5.util.Args;
47
48 /**
49 * <p>
50 * The {@code RequestIfRange} interceptor ensures that the request adheres to the RFC guidelines for the 'If-Range' header.
51 * The "If-Range" header field is used in conjunction with the Range header to conditionally request parts of a representation.
52 * If the validator given in the "If-Range" header matches the current validator for the representation, then the server should respond with the specified range of the document.
53 * If they do not match, the server should return the entire representation.
54 * </p>
55 *
56 * <p>
57 * Key points:
58 * </p>
59 * <ul>
60 * <li>A client MUST NOT generate an If-Range header field in a request that does not contain a Range header field.</li>
61 * <li>An origin server MUST ignore an If-Range header field received in a request for a target resource that does not support Range requests.</li>
62 * <li>A client MUST NOT generate an If-Range header field containing an entity tag that is marked as weak.</li>
63 * <li>A client MUST NOT generate an If-Range header field containing an HTTP-date unless the client has no entity tag for the corresponding representation and the date is a strong validator.</li>
64 * <li>A server that receives an If-Range header field on a Range request MUST evaluate the condition before performing the method.</li>
65 * </ul>
66 *
67 * @since 5.4
68 */
69 @Contract(threading = ThreadingBehavior.IMMUTABLE)
70 public class RequestIfRange implements HttpRequestInterceptor {
71
72 /**
73 * Singleton instance.
74 *
75 * @since 5.4
76 */
77 public static final RequestIfRange INSTANCE = new RequestIfRange();
78
79 public RequestIfRange() {
80 super();
81 }
82
83 /**
84 * Processes the given request to ensure it adheres to the RFC guidelines for the 'If-Range' header.
85 *
86 * @param request The HTTP request to be processed.
87 * @param entity The entity details of the request.
88 * @param context The HTTP context.
89 * @throws HttpException If the request does not adhere to the RFC guidelines.
90 * @throws IOException If an I/O error occurs.
91 */
92 @Override
93 public void process(final HttpRequest request, final EntityDetails entity, final HttpContext context)
94 throws HttpException, IOException {
95 Args.notNull(request, "HTTP request");
96
97 final Header ifRangeHeader = request.getFirstHeader(HttpHeaders.IF_RANGE);
98
99 // If there's no If-Range header, just return
100 if (ifRangeHeader == null) {
101 return;
102 }
103
104 // If there's an If-Range header but no Range header, throw an exception
105 if (!request.containsHeader(HttpHeaders.RANGE)) {
106 throw new ProtocolException("Request with 'If-Range' header must also contain a 'Range' header.");
107 }
108
109 final Header eTag = request.getFirstHeader(HttpHeaders.ETAG);
110
111 // If there's a weak ETag in the If-Range header, throw an exception
112 if (eTag != null && eTag.getValue().startsWith("W/")) {
113 throw new ProtocolException("'If-Range' header must not contain a weak entity tag.");
114 }
115
116 final Instant dateInstant = DateUtils.parseStandardDate(request, HttpHeaders.DATE);
117
118 if (dateInstant == null) {
119 return;
120 }
121
122 final Instant lastModifiedInstant = DateUtils.parseStandardDate(request, HttpHeaders.LAST_MODIFIED);
123
124 if (lastModifiedInstant == null) {
125 // If there's no Last-Modified header, we exit early because we can't deduce that it is strong.
126 return;
127 }
128
129 // If the difference between the Last-Modified and Date headers is less than 1 second, throw an exception
130 if (lastModifiedInstant.plusSeconds(1).isAfter(dateInstant) && eTag != null) {
131 throw new ProtocolException("'If-Range' header with a Date must be a strong validator.");
132 }
133 }
134
135 }