1 /*
2 * Copyright 2010-2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License").
5 * You may not use this file except in compliance with the License.
6 * A copy of the License is located at
7 *
8 * http://aws.amazon.com/apache2.0
9 *
10 * or in the "license" file accompanying this file. This file is distributed
11 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
12 * express or implied. See the License for the specific language governing
13 * permissions and limitations under the License.
14 */
15 package com.amazonaws.services.s3.internal;
16
17 import com.amazonaws.services.s3.model.IllegalBucketNameException;
18
19 import java.util.regex.Pattern;
20
21 /**
22 * Utilities for working with Amazon S3 bucket names, such as validation and
23 * checked to see if they are compatible with DNS addressing.
24 */
25 public enum BucketNameUtils {
26 ;
27 private static final int MIN_BUCKET_NAME_LENGTH = 3;
28 private static final int MAX_BUCKET_NAME_LENGTH = 63;
29
30 private static final Pattern ipAddressPattern = Pattern.compile("(\\d+\\.){3}\\d+");
31
32 /**
33 * Validates that the specified bucket name is valid for Amazon S3 V2 naming
34 * (i.e. DNS addressable in virtual host style). Throws an
35 * IllegalArgumentException if the bucket name is not valid.
36 * <p>
37 * S3 bucket naming guidelines are specified in <a href="http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?BucketRestrictions.html"
38 * > http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?
39 * BucketRestrictions.html</a>
40 *
41 * @param bucketName
42 * The bucket name to validate.
43 *
44 * @throws IllegalBucketNameException
45 * If the specified bucket name doesn't follow Amazon S3's
46 * guidelines.
47 */
48 public static void validateBucketName(final String bucketName) {
49 isValidV2BucketName(bucketName, true);
50 }
51
52 /**
53 * Returns true if the specified bucket name can be addressed using V2,
54 * virtual host style, addressing. Otherwise, returns false indicating that
55 * the bucket must be addressed using V1, path style, addressing.
56 *
57 * @param bucketName
58 * The name of the bucket to check.
59 *
60 * @return True if the specified bucket name can be addressed in V2, virtual
61 * host style, addressing otherwise false if V1, path style,
62 * addressing is required.
63 */
64 public static boolean isValidV2BucketName(String bucketName) {
65 return isValidV2BucketName(bucketName, false);
66 }
67
68 /**
69 * Convience method that allows the DNS rules to be altered for different SDKs.
70 */
71 public static boolean isDNSBucketName(String bucketName) {
72 return isValidV2BucketName( bucketName );
73 }
74
75 /**
76 * Validate whether the given input is a valid bucket name. If throwOnError
77 * is true, throw an IllegalArgumentException if validation fails. If
78 * false, simply return 'false'.
79 *
80 * @param bucketName the name of the bucket
81 * @param throwOnError true to throw exceptions on failure
82 * @return true if the name is valid, false if not
83 */
84 private static boolean isValidV2BucketName(final String bucketName,
85 final boolean throwOnError) {
86
87 if (bucketName == null) {
88 return exception(throwOnError, "Bucket name cannot be null");
89 }
90
91 if (bucketName.length() < MIN_BUCKET_NAME_LENGTH ||
92 bucketName.length() > MAX_BUCKET_NAME_LENGTH) {
93
94 return exception(
95 throwOnError,
96 "Bucket name should be between " + MIN_BUCKET_NAME_LENGTH + " and " + MAX_BUCKET_NAME_LENGTH +" characters long"
97 );
98 }
99
100 if (ipAddressPattern.matcher(bucketName).matches()) {
101 return exception(
102 throwOnError,
103 "Bucket name must not be formatted as an IP Address"
104 );
105 }
106
107 char previous = '\0';
108
109 for (int i = 0; i < bucketName.length(); ++i) {
110 char next = bucketName.charAt(i);
111
112 if (next >= 'A' && next <= 'Z') {
113 return exception(
114 throwOnError,
115 "Bucket name should not contain uppercase characters"
116 );
117 }
118
119 if (next == ' ' || next == '\t' || next == '\r' || next == '\n') {
120 return exception(
121 throwOnError,
122 "Bucket name should not contain white space"
123 );
124 }
125
126 if (next == '.') {
127 if (previous == '\0') {
128 return exception(
129 throwOnError,
130 "Bucket name should not begin with a period"
131 );
132 }
133 if (previous == '.') {
134 return exception(
135 throwOnError,
136 "Bucket name should not contain two adjacent periods"
137 );
138 }
139 if (previous == '-') {
140 return exception(
141 throwOnError,
142 "Bucket name should not contain dashes next to periods"
143 );
144 }
145 } else if (next == '-') {
146 if (previous == '.') {
147 return exception(
148 throwOnError,
149 "Bucket name should not contain dashes next to periods"
150 );
151 }
152 if (previous == '\0') {
153 return exception(
154 throwOnError,
155 "Bucket name should not begin with a '-'"
156 );
157 }
158 } else if ((next < '0')
159 || (next > '9' && next < 'a')
160 || (next > 'z')) {
161
162 return exception(
163 throwOnError,
164 "Bucket name should not contain '" + next + "'"
165 );
166 }
167
168 previous = next;
169 }
170
171 if (previous == '.' || previous == '-') {
172 return exception(
173 throwOnError,
174 "Bucket name should not end with '-' or '.'"
175 );
176 }
177
178 return true;
179 }
180
181 /**
182 * If 'exception' is true, throw an IllegalBucketNameException with the given
183 * message. Otherwise, silently return false.
184 *
185 * @param exception true to throw an exception
186 * @param message the message for the exception
187 * @return false if 'exception' is false
188 */
189 private static boolean exception(final boolean exception, final String message) {
190 if (exception) {
191 throw new IllegalBucketNameException(message);
192 }
193 return false;
194 }
195 }
196