| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.logging.log4j.core.util; |
| |
| import org.apache.logging.log4j.util.Strings; |
| |
| |
| /** |
| * Utility class for transforming strings. |
| */ |
| public final class Transform { |
| |
| private static final String CDATA_START = "<![CDATA["; |
| private static final String CDATA_END = "]]>"; |
| private static final String CDATA_PSEUDO_END = "]]>"; |
| private static final String CDATA_EMBEDED_END = CDATA_END + CDATA_PSEUDO_END + CDATA_START; |
| private static final int CDATA_END_LEN = CDATA_END.length(); |
| |
| private Transform() { |
| } |
| |
| /** |
| * This method takes a string which may contain HTML tags (ie, |
| * <b>, <table>, etc) and replaces any |
| * '<', '>' , '&' or '"' |
| * characters with respective predefined entity references. |
| * |
| * @param input The text to be converted. |
| * @return The input string with the special characters replaced. |
| */ |
| public static String escapeHtmlTags(final String input) { |
| //Check if the string is null, zero length or devoid of special characters |
| // if so, return what was sent in. |
| |
| if (Strings.isEmpty(input) |
| || (input.indexOf('"') == -1 && |
| input.indexOf('&') == -1 && |
| input.indexOf('<') == -1 && |
| input.indexOf('>') == -1)) { |
| return input; |
| } |
| |
| //Use a StringBuilder in lieu of String concatenation -- it is |
| //much more efficient this way. |
| |
| final StringBuilder buf = new StringBuilder(input.length() + 6); |
| char ch = ' '; |
| |
| final int len = input.length(); |
| for (int i = 0; i < len; i++) { |
| ch = input.charAt(i); |
| if (ch > '>') { |
| buf.append(ch); |
| } else if (ch == '<') { |
| buf.append("<"); |
| } else if (ch == '>') { |
| buf.append(">"); |
| } else if (ch == '&') { |
| buf.append("&"); |
| } else if (ch == '"') { |
| buf.append("""); |
| } else { |
| buf.append(ch); |
| } |
| } |
| return buf.toString(); |
| } |
| |
| /** |
| * Ensures that embedded CDEnd strings (]]>) are handled properly |
| * within message, NDC and throwable tag text. |
| * |
| * @param buf StringBuilder holding the XML data to this point. The |
| * initial CDStart (<![CDATA[) and final CDEnd (]]>) of the CDATA |
| * section are the responsibility of the calling method. |
| * @param str The String that is inserted into an existing CDATA Section within buf. |
| */ |
| public static void appendEscapingCData(final StringBuilder buf, final String str) { |
| if (str != null) { |
| int end = str.indexOf(CDATA_END); |
| if (end < 0) { |
| buf.append(str); |
| } else { |
| int start = 0; |
| while (end > -1) { |
| buf.append(str.substring(start, end)); |
| buf.append(CDATA_EMBEDED_END); |
| start = end + CDATA_END_LEN; |
| if (start < str.length()) { |
| end = str.indexOf(CDATA_END, start); |
| } else { |
| return; |
| } |
| } |
| buf.append(str.substring(start)); |
| } |
| } |
| } |
| |
| /** |
| * This method takes a string which may contain JSON reserved chars and |
| * escapes them. |
| * |
| * @param input The text to be converted. |
| * @return The input string with the special characters replaced. |
| */ |
| public static String escapeJsonControlCharacters(final String input) { |
| // Check if the string is null, zero length or devoid of special characters |
| // if so, return what was sent in. |
| |
| // TODO: escaped Unicode chars. |
| |
| if (Strings.isEmpty(input) |
| || (input.indexOf('"') == -1 && |
| input.indexOf('\\') == -1 && |
| input.indexOf('/') == -1 && |
| input.indexOf('\b') == -1 && |
| input.indexOf('\f') == -1 && |
| input.indexOf('\n') == -1 && |
| input.indexOf('\r') == -1 && |
| input.indexOf('\t') == -1)) { |
| return input; |
| } |
| |
| final StringBuilder buf = new StringBuilder(input.length() + 6); |
| |
| final int len = input.length(); |
| for (int i = 0; i < len; i++) { |
| final char ch = input.charAt(i); |
| final String escBs = "\\"; |
| switch (ch) { |
| case '"': |
| buf.append(escBs); |
| buf.append(ch); |
| break; |
| case '\\': |
| buf.append(escBs); |
| buf.append(ch); |
| break; |
| case '/': |
| buf.append(escBs); |
| buf.append(ch); |
| break; |
| case '\b': |
| buf.append(escBs); |
| buf.append('b'); |
| break; |
| case '\f': |
| buf.append(escBs); |
| buf.append('f'); |
| break; |
| case '\n': |
| buf.append(escBs); |
| buf.append('n'); |
| break; |
| case '\r': |
| buf.append(escBs); |
| buf.append('r'); |
| break; |
| case '\t': |
| buf.append(escBs); |
| buf.append('t'); |
| break; |
| default: |
| buf.append(ch); |
| } |
| } |
| return buf.toString(); |
| } |
| } |