/*
* Copyright 2010-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.services.s3.internal;
/**
* Utilities for working with Amazon S3 bucket names, such as validation and
* checked to see if they are compatible with DNS addressing.
*/
public enum BucketNameUtils {
;
private static final int MIN_BUCKET_NAME_LENGTH = 3;
private static final int MAX_BUCKET_NAME_LENGTH = 63;
/**
* Validates that the specified bucket name is valid for Amazon S3 V2 naming
* (i.e. DNS addressable in virtual host style). Throws an
* IllegalArgumentException if the bucket name is not valid.
* <p>
* S3 bucket naming guidelines are specified in <a href=
* "http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?BucketRestrictions.html"
* > http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?
* BucketRestrictions.html</a>
*
* @param bucketName The bucket name to validate.
* @throws IllegalArgumentException If the specified bucket name doesn't
* follow Amazon S3's guidelines.
*/
public static void validateBucketName(final String bucketName) {
isValidV2BucketName(bucketName, true);
}
/**
* Returns true if the specified bucket name can be addressed using V2,
* virtual host style, addressing. Otherwise, returns false indicating that
* the bucket must be addressed using V1, path style, addressing.
*
* @param bucketName The name of the bucket to check.
* @return True if the specified bucket name can be addressed in V2, virtual
* host style, addressing otherwise false if V1, path style,
* addressing is required.
*/
public static boolean isValidV2BucketName(String bucketName) {
return isValidV2BucketName(bucketName, false);
}
/**
* Convience method that allows the DNS rules to be altered for different
* SDKs.
*/
public static boolean isDNSBucketName(String bucketName) {
return isValidV2BucketName(bucketName);
}
/**
* Validate whether the given input is a valid bucket name. If throwOnError
* is true, throw an IllegalArgumentException if validation fails. If false,
* simply return 'false'.
*
* @param bucketName the name of the bucket
* @param throwOnError true to throw exceptions on failure
* @return true if the name is valid, false if not
*/
private static boolean isValidV2BucketName(final String bucketName,
final boolean throwOnError) {
if (bucketName == null) {
return exception(throwOnError, "Bucket name cannot be null");
}
if (bucketName.length() < MIN_BUCKET_NAME_LENGTH ||
bucketName.length() > MAX_BUCKET_NAME_LENGTH) {
return exception(
throwOnError,
"Bucket name should be between 3 and 63 characters long");
}
char previous = '\0';
for (int i = 0; i < bucketName.length(); ++i) {
char next = bucketName.charAt(i);
if (next >= 'A' && next <= 'Z') {
return exception(
throwOnError,
"Bucket name should not contain uppercase characters");
}
if (next == ' ' || next == '\t' || next == '\r' || next == '\n') {
return exception(
throwOnError,
"Bucket name should not contain white space");
}
if (next == '.') {
if (previous == '.') {
return exception(
throwOnError,
"Bucket name should not contain two adjacent periods");
}
if (previous == '-') {
return exception(
throwOnError,
"Bucket name should not contain dashes next to periods");
}
/**
* . in bucket name may cause host name verification failure
* when using virtual host style addressing. return false to
* fall back to path style addressing.
*/
return false;
} else if (next == '-') {
if (previous == '.') {
return exception(
throwOnError,
"Bucket name should not contain dashes next to periods");
}
} else if ((next < '0')
|| (next > '9' && next < 'a')
|| (next > 'z')) {
return exception(
throwOnError,
"Bucket name should not contain '" + next + "'");
}
previous = next;
}
if (previous == '.' || previous == '-') {
return exception(
throwOnError,
"Bucket name should not end with '-' or '.'");
}
return true;
}
/**
* If 'exception' is true, throw an IllegalArgumentException with the given
* message. Otherwise, silently return false.
*
* @param exception true to throw an exception
* @param message the message for the exception
* @return false if 'exception' is false
*/
private static boolean exception(final boolean exception, final String message) {
if (exception) {
throw new IllegalArgumentException(message);
}
return false;
}
}