Created
November 6, 2017 22:23
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Base64UrlEncoding
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| /* | |
| * Copyright (C) 2014 jsonwebtoken.io | |
| * | |
| * Licensed 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 io.jsonwebtoken.impl; | |
| public class Base64UrlCodec extends AbstractTextCodec { | |
| @Override | |
| public String encode(byte[] data) { | |
| String base64Text = TextCodec.BASE64.encode(data); | |
| byte[] bytes = base64Text.getBytes(US_ASCII); | |
| //base64url encoding doesn't use padding chars: | |
| bytes = removePadding(bytes); | |
| //replace URL-unfriendly Base64 chars to url-friendly ones: | |
| for (int i = 0; i < bytes.length; i++) { | |
| if (bytes[i] == '+') { | |
| bytes[i] = '-'; | |
| } else if (bytes[i] == '/') { | |
| bytes[i] = '_'; | |
| } | |
| } | |
| return new String(bytes, US_ASCII); | |
| } | |
| protected byte[] removePadding(byte[] bytes) { | |
| byte[] result = bytes; | |
| int paddingCount = 0; | |
| for (int i = bytes.length - 1; i > 0; i--) { | |
| if (bytes[i] == '=') { | |
| paddingCount++; | |
| } else { | |
| break; | |
| } | |
| } | |
| if (paddingCount > 0) { | |
| result = new byte[bytes.length - paddingCount]; | |
| System.arraycopy(bytes, 0, result, 0, bytes.length - paddingCount); | |
| } | |
| return result; | |
| } | |
| @Override | |
| public byte[] decode(String encoded) { | |
| char[] chars = encoded.toCharArray(); //always ASCII - one char == 1 byte | |
| //Base64 requires padding to be in place before decoding, so add it if necessary: | |
| chars = ensurePadding(chars); | |
| //Replace url-friendly chars back to normal Base64 chars: | |
| for (int i = 0; i < chars.length; i++) { | |
| if (chars[i] == '-') { | |
| chars[i] = '+'; | |
| } else if (chars[i] == '_') { | |
| chars[i] = '/'; | |
| } | |
| } | |
| String base64Text = new String(chars); | |
| return TextCodec.BASE64.decode(base64Text); | |
| } | |
| protected char[] ensurePadding(char[] chars) { | |
| char[] result = chars; //assume argument in case no padding is necessary | |
| int paddingCount = 0; | |
| //fix for https://github.com/jwtk/jjwt/issues/31 | |
| int remainder = chars.length % 4; | |
| if (remainder == 2 || remainder == 3) { | |
| paddingCount = 4 - remainder; | |
| } | |
| if (paddingCount > 0) { | |
| result = new char[chars.length + paddingCount]; | |
| System.arraycopy(chars, 0, result, 0, chars.length); | |
| for (int i = 0; i < paddingCount; i++) { | |
| result[chars.length + i] = '='; | |
| } | |
| } | |
| return result; | |
| } | |
| } |
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