001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.util;
018
019/**
020 * Utility class for JavaScript escaping.
021 * Escapes based on the JavaScript 1.5 recommendation.
022 *
023 * <p>Reference:
024 * <a href="https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Values,_variables,_and_literals#String_literals">
025 * JavaScript Guide</a> on Mozilla Developer Network.
026 *
027 * @author Juergen Hoeller
028 * @author Rob Harrop
029 * @author Rossen Stoyanchev
030 * @since 1.1.1
031 */
032public abstract class JavaScriptUtils {
033
034        /**
035         * Turn JavaScript special characters into escaped characters.
036         * @param input the input string
037         * @return the string with escaped characters
038         */
039        public static String javaScriptEscape(String input) {
040                StringBuilder filtered = new StringBuilder(input.length());
041                char prevChar = '\u0000';
042                char c;
043                for (int i = 0; i < input.length(); i++) {
044                        c = input.charAt(i);
045                        if (c == '"') {
046                                filtered.append("\\\"");
047                        }
048                        else if (c == '\'') {
049                                filtered.append("\\'");
050                        }
051                        else if (c == '\\') {
052                                filtered.append("\\\\");
053                        }
054                        else if (c == '/') {
055                                filtered.append("\\/");
056                        }
057                        else if (c == '\t') {
058                                filtered.append("\\t");
059                        }
060                        else if (c == '\n') {
061                                if (prevChar != '\r') {
062                                        filtered.append("\\n");
063                                }
064                        }
065                        else if (c == '\r') {
066                                filtered.append("\\n");
067                        }
068                        else if (c == '\f') {
069                                filtered.append("\\f");
070                        }
071                        else if (c == '\b') {
072                                filtered.append("\\b");
073                        }
074                        // No '\v' in Java, use octal value for VT ascii char
075                        else if (c == '\013') {
076                                filtered.append("\\v");
077                        }
078                        else if (c == '<') {
079                                filtered.append("\\u003C");
080                        }
081                        else if (c == '>') {
082                                filtered.append("\\u003E");
083                        }
084                        // Unicode for PS (line terminator in ECMA-262)
085                        else if (c == '\u2028') {
086                                filtered.append("\\u2028");
087                        }
088                        // Unicode for LS (line terminator in ECMA-262)
089                        else if (c == '\u2029') {
090                                filtered.append("\\u2029");
091                        }
092                        else {
093                                filtered.append(c);
094                        }
095                        prevChar = c;
096
097                }
098                return filtered.toString();
099        }
100
101}